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In the north Patagonian region of the Argentinean Continental Shelf, the San Jorge Gulf (SJG; 45°‐47°S, 65°30ʹ‐67°30ʹW) is the main nursery ground of age‐0+ Argentine hake Merluccius hubbsi Marini, 1933, one of the most important fishery resources in Argentina. The gulf exhibits strong seasonal and spatial fluctuations in environmental features, which might affect survival of age‐0+ individuals and recruitment to the adult population. Our main goal was to evaluate the seasonal and spatial dynamics of their nutritional status within the SJG in winter 2016, spring 2016 and summer 2017. Condition indices (relative condition factor Kn, hepatosomatic index HSI and liver lipid content %L) and diet information (feeding incidence and relative importance of prey) were combined with physical (temperature and salinity) and biological (satellite chlorophyll‐a concentration; chl‐a) data. Age‐0+ condition indices and prey intake showed significant seasonal variations, with minimum values in winter, intermediate in summer and maximum in spring, strongly coupled to the mean chl‐a concentration in each season. Herbivorous euphausiids Euphausia spp. were the preferred prey along the study period. A bottom‐up effect on condition of age‐0+ hake is suggested, manifested as lower condition values in winter, the less productive season. Spatially, better conditioned individuals matched sectors of the gulf where chl‐a concentrations were higher, coupled to the presence of frontal systems. Monitoring age‐0+ hake nutritional status is relevant in the current global change scenario, which might modify phytoplankton biomass and composition and, consequently, the herbivorous zooplankton abundances. Fil: Temperoni, Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Massa, Agueda Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Martos, Patricia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; Argentina Fil: Marrari, Marina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The aims of this study were to estimate seasonal spore availability in the carrageenophyte Gigartina skottsbergii from the Patagonian Atlantic coast, evaluate the effect of induction methods and culture conditions on spore release, and assess spore settlement on different substrates. Fertile fronds were collected in southern Argentina. The density and size of reproductive structures and spore output were registered seasonally. Spore release was evaluated using different induction methods and conditions. Finally, different natural substrates were assessed for spore settlement. Spore availability is restricted to winter and spring. Cystocarps and tetrasporangial sori reached maturity towards winter, and spores were released in large amounts during winter and spring, with higher tetraspore than carpospore release. Spontaneous discharge would appear to be a more advisable induction method than desiccation and high salinity. Temperature and photoperiod did not have a significant effect on total spore output. After 2 weeks of incubation, no differences were found among spore densities on glass, pebbles, clams, or mussels. Despite the low survival rate registered on all substrates, spores germinated and developed healthily. This is the first study to evaluate carpospore and tetraspore availability throughout the year and the viability of in vitro spore culture of G. skottsbergii from the South American Atlantic coast. Fil: Hughes, Melanie Hebe. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Michetti, Karina Mariel. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina

The feeding ecology of farmed fish escapees has seldom been assessed, although they are one of aquaculture’s main environmental impacts. Here we tested if the diet of Oncorhynchus mykiss rainbow trout escapees was affected by their dispersal from farms in a reservoir in Argentine Patagonia by combining stomach content and stable isotope data, and compared their spatial patterns with those of caged and wild (previously naturalized) conspecifics. Our results reveal a shift in the stomach content and δ13C values of escapees, reflecting a farm (pellets) to wild (mainly Daphnia sp.) diet transition associated to dispersal from farms. The δ13C signal of escapees sampled within the farming area was close to that of caged fish, whereas the δ13C of escapees captured far from it was indistinguishable from that of wild rainbow trout. Furthermore, escapee dispersal from farms was associated with a transition from indiscriminate surface feeding (on indigestible floating items) typical of caged fish to preying heavily on Daphnia sp. In contrast, wild fish diet was homogeneous across all sites. Farm escapees gradually acquiring the feeding behavior of their wild conspecifics as they disperse from the farms may promote competition for food and space, and increase their chances for survival in the wild. Fil: Nabaes Jodar, Diego Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentina Fil: Cussac, Victor Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentina Fil: Becker, Leandro Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina

Estuarine abiotic characteristics vary with tidal variations and fresh water input, both driven by climatic conditions and often cyclical climatic events. Estuaries are very productive and bivalves often represent a substantial proportion of the biomass with important ecological role. Salinity fluctuation is often a key environmental factor affecting bivalves shell growth and individual condition index (CI), parameters that in turn can be used to show the quality of the environment for one population. The stout razor clam Tagelus plebeius is an euryhaline filter-feeder species that inhabits sandy-silt tidal flats within a wide salinity range. The objective of this study was to evaluate, by survey sampling and in situ transplant experiments among sites with different salinity, whether shell growth and CI of T. plebeius vary with the salinity regime. We hypothesized a higher growth and CI related to the intermediate salinity. Clams and abiotic parameters were sampled in three estuaries of the northern Argentinian coast with different salinity regimes (Bahía Samborombón (36°19′S), Mar Chiquita coastal lagoon (37°32′S) and Bahía Blanca (38° 47′S)) and in three sites along the salinity gradient of the Mar Chiquita coastal lagoon where the manipulative experiments were also conducted. Shells were more elongated in sites with lower salinity; but the growth rate (k) and the CI were higher in sites with intermediate salinity. Furthermore, clams transplanted from intermediate salinity sites to those with higher or lower salinity showed a disadvantage in shell growth. Considering the scenario of climatic-driven salinity changes in these estuaries and given that T. plebeius is the only native bivalve species in those intertidal zones, having a relevant ecological role and conspicuous fossil presence in Holocene outcrops, our results highlight the relevance of this clam as a valuable target for future studies on conservation biology and paleobiology. Fil: Addino, Mariana del Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Alvarez, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Brey, Thomas. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Lomovasky, Betina Judith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Live transport to markets requires a baseline on the effects of temperature during air-exposure and the subsequent recovery in water. Our aim was to analyze the physiological effect of 24 h of air exposure in commercial male Lithodes santolla at different temperatures and subsequent re-immersion. Three groups of animals were air-exposed at three temperatures (4 °C, 8 °C and 12 °C) for 24 h, and then re-submersed for 12 h. The control group was kept in water at 8 °C. Samples of haemolymph were extracted after air exposure and re-immersed. We measured superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), ascorbic acid (AA), and protein oxidation (PO). Animals exposed at 12 °C died during emersion. Almost all measured parameters changed with air exposure and temperature. The total recovery of most of the analyzed oxidative stress parameters was attained only at 8 °C, where SOD, CAT and GPx, AA, glucose, and pH returned to values similar to the control group. In animals exposed at 4 °C, only SOD and AA returned to basal levels. Acclimation temperature is an important parameter to consider in the shipping-stock chain of L. santolla, since changes in temperature might be an extra factor of stress during recovery of the animal, besides the reperfusion itself. Fil: Schvezov, Natasha. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Tapella, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Gowland Sainz, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Romero, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

Southern right whale (Eubalaena australis) populations were severelydepleted in past centuries by intensive whaling, but many are now recover-ing after receiving international protection in 1935 (IWC 2012). In the SouthAtlantic, the population of southern right whales that migrates each australwinter to calve at Península Valdés, Argentina (Payne 1986; IWC 2001,2012), began experiencing unusually high calf deaths in 2003. The deathspeaked in 2012 with 113 dead calves (Rowntreeet al. 2013, Sironiet al.2018). The estimated age of dead calves ranged from 1 d to 4–6mo(Rowntreeet al. 2013, McAlooseet al. 2016). Fil: Sironi, Mariano Miguel. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica. Cátedra de Biología del Comportam. y Div. Animal Ii; Argentina. Instituto de Conservacion de Ballenas; Argentina Fil: Marón, Carina Flavia. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica. Cátedra de Biología del Comportam. y Div. Animal Ii; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Petitte, Luis. Southern Spirit Whale Watch; Argentina Fil: Guevara, Justa. Southern Spirit Whale Watch; Argentina Fil: Martorel, Juan Pablo. Southern Spirit Whale Watch; Argentina Fil: Rowntree, Victoria J.. University Of Utah. Department Of Biology; Estados Unidos

The rule of thumb in marine trophodynamics indicates that the bigger an organism, the higher its trophic level (TROPH). This generalization leads to the assumption that fishes increase their TROPH with growth. However, a recent review showed that for many species, TROPH does not increase with body size, suggesting that size-independent feeding is not rare in marine fishes. Here, we assessed some morphological traits of marine fishes that could potentially be used as indicators for the ability to vary TROPH with body size. Stable isotope values of nitrogen were used as a proxy TROPH. The specific objectives were as follows: (a) to evaluate the relationship between the oral gape and the trophodynamic trend and (b) to quantify the relevance of 11 external morphological traits in determining the size-based trophodynamics. We used random forest models to identify the morphological traits that would help predict which species would have the potential to increase TROPH with growth and which would have not. The selected traits included the pelvic fin relative position, the dorsal fin shape, total length, and relative mouth size. Our results also showed a marked relationship between the rate of increase in the oral gape and TROPH. The analyses presented here provide the first comprehensive and quantitative review aiming at linking the trophodynamics of marine fishes with external morphological traits. Fil: Rios, Maria Florencia. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Sede Puerto Madryn; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Venerus, Leonardo Ariel. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Karachle, Paraskevi K.. Hellenic Centre for Marine Research. Institute of Marine Biological Resources and Inland Waters; Grecia Fil: Reid, William D. K.. University of Newcastle; Reino Unido Fil: Erzini, Karim. Universidad de Algarve; Portugal Fil: Stergiou, Konstantinos I.. Aristotle University of Thessaloniki. Department of Zoology. School of Biology; Grecia Fil: Galvan, David Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina

A batch culture experiment was conducted to study the interactive effects of ocean acidification (OA) and solar ultraviolet radiation (UVR, 280–400 nm) on the harmful dinoflagellate Karenia mikimotoi. Cells were incubated in 7-days trials under four treatments. Physiological (growth, pigments, UVabc) and toxicity (hemolytic activity and its toxicity to zebrafish embryos) response variables were measured in four treatments, representing two factorial combinations of CO2 (400 and 1000 μatm) and solar irradiance (with or without UVR). Toxic species K. mikimotoi showed sustained growth in all treatments, and there was not statistically significant difference among four treatments. Cell pigment content decreased, but UVabc and hemolytic activity increased in all HC treatments and PAB conditions. The toxicity to zebrafish embryos of K. mikimotoi was not significantly different among four treatments. All HC and UVR conditions and the combinations of HC*UVR (HC-PAB) positively affected the UVabc, hemolytic activity in comparison to the LC*P (LC-P) treatment, and negatively affected the pigments. Ocean acidification (OA) was probably the main factor that affected the chlorophyll-a (Chl-a) and UVabc, but UVR was the main factor that affected the carotenoid (Caro) and hemolytic activity. There were no significant interactive effects of OA*UVR on growth, toxicity to zebrafish embryos. If these results are extrapolated to the natural environment, it can be hypothesized that this strain (DP-C32) of K. mikimotoi cells have the efficient mechanisms to endure the combination of ocean acidification and solar UVR. It is assumed that this toxic strain could form harmful bloom and enlarge the threatening to coastal communities, marine animals, even human health under future conditions. Fil: Wang, Xinjie. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Feng, Xinqian. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Zhuang, Yang. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Lu, Jianghuan. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Wang, Yang. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Gonçalves, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Li, Xi. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China. The Affiliated Kangning Hospital of Wenzhou Medical University; China Fil: Lou, Yongliang. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China Fil: Guan, Wanchun. Wenzhou Medical University. School of Laboratory Medicine and Life Science. Department of Marine Biotechnology; China

Functional diversity is the component of diversity that influences ecosystem dynamics, stability, productivity, nutrient balance, and other aspects of ecosystem functioning. We evaluate the spatio-temporal variability of the functional traits (biological traits analysis), functional diversity indices (functional richness, functional evenness, functional divergence and functional dispersion) and AZTI marine biotic index in response to the distinct levels of sewage contamination at different sites on intertidal abrasion platforms. Variations in macrobenthic functional structure between reference and impacted sites were evident in the study area. The functional richness showed a pattern with higher values in the reference sites; Functional evenness showed a similar pattern, but only during spring. Functional divergence presented lower values in the impacted sites during autumn and spring. The functional diversity indices (functional richness and functional evenness) and the AZTI marine biotic index presented a negative relationship, indicating that functional diversity is related to benthic environmental health. Thus, biological traits analysis and functional diversity indices, especially FRic that reveals differences in macrobenthic functional structure between impacted and reference sites during all seasons, represent an informative and useful tool to describe the different aspects of sewage impacts in benthic assemblages on rocky shores. These analyses have a high potential for future monitoring programmes. Fil: Garaffo, Griselda Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Jaubet, Maria Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Llanos, Elizabeth Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Saracho Bottero, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Elias, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Cultural eutrophication has promoted theapplication of several mitigation strategies in the last50 years. In this study we tested the combined effectsof two techniques: calcium hydroxide [(Ca(OH)2),lime] and a free-floating macrophyte (Salvinia rotundifoliaWilld) to examine the soluble reactive phosphorusremoval capability and the effects on plankton(phytoplankton and zooplankton) structure in a in situlake mesocosms experiment. The experiment lasted10 days (n = 12, 500 l each) with a control and threetreatments (lime (CH), plants (FM), and thecombination of both (CH ? FM)). Samples of severalphysical and chemical variables (including nutrients)and phytoplankton were taken at the beginning, 2 daysafter, 4 days, and 10 days (end of the experiment).Zooplankton was sampled at the beginning and at theend. The highest depletion effect of soluble reactivephosphorus (SRP) was observed in presence of lime.Phytoplankton biovolume was highly and negativelyaffected in lime treatments (CH and CH ? FM).Zooplankton changed from Rotifera to Cladocera andCopepoda in presence of macrophytes. We concludethat lime ? plants reduces more effectively SRP,phytoplankton biovolume and promotes herbivorouszooplankton development; becoming by this way, in asuitable mitigation strategy to be explored in futurefield manipulation studies. Fil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Spies, Mariana. Universidad Nacional del Litoral; Argentina Fil: Battauz, Yamila Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Medrano, Jonathan. Universidad Autónoma de Entre Ríos; Argentina Fil: Sinistro, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

The main goal of this study was to examine the nutritional condition of Engraulis anchoita larvae during the austral spring-summer seasons of 2010/2011 and 2012/2013 in highly productive waters in the southwestern Atlantic Ocean called El Rincón. RNA/DNA (RDs) index and derived index of Growth performance (Gpf) were used. Significant differences were observed in average RDs indices for 2010/2011 (5.27 ± 3.26) and 2012/2013 (0.81 ± 0.44). A difference in the years was also observed in Growth performance with higher values in 2010/2011 (2.45 ± 1.83) compared to 2012/2013 (−0.03 ± 0.25). Anchovy larvae captured in 2010/2011 were in good condition (Gpf > 1). During 2012/2013, extremely high larval densities were observed although Gpf values were very low indicating poor larval condition. Chlorophyll dynamics differed between sampled periods, with higher maximum values during spring 2012 as compared to 2010. Concerning chlorophyll concentrations showed a sharp decline in the values for the rest of the 2012/2013 season. We propose that the low larval growth and condition observed during 2012/2013 may have resulted from a decrease in chlorophyll concentrations together with very large larval densities which enhanced the competition for food within the larval population. Our results reinforce the idea that satellite ocean color products can be valuable tools for understanding variability in ecosystem dynamics and its effects on reproductive success in fish. Fil: Diaz, Marina Vera. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Marrari, Marina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Casa, Valeria. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gattás, Florencia María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina Fil: Pajaro, Marcelo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Macchi, Gustavo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina

Neohelice granulata provides an interesting animal model for studying behavioural process because it is widely distributed, ensuring variability related to different environmental conditions. The aim of this study was to analyse variation in site fidelity with relation to landscape heterogeneity. Field observations were carried out in three geographically distant marshes in Argentina (Mar Chiquita, San Antonio Oeste, and Riacho San José), which differ in their environmental characteristics and where crabs display different reproductive strategies. We analysed potential variation in burrow fidelity with relation to body size, sex and presence of vegetation (mudflat and saltmarsh) at all study sites. In addition, we analysed the influence of tidal flooding on fidelity in the Mar Chiquita saltmarsh. To achieve these goals, we used a mark-recapture method in which we tagged approximately 100 crabs during mid-summer for each zone at each site (a total of 668 crabs) for geographical comparison and approximately 370 crabs to evaluate the influence of tidal flooding. We found more faithful individuals in Mar Chiquita than in San Antonio Oeste and Riacho San José. For the San Antonio Oeste and Riacho San José populations and for Mar Chiquita previous to flooding samples we also found differences in site fidelity related to crab body size. At San Antonio Oeste and Riacho San José the relationship between size and proportion of faithful crabs was negative (smaller crabs were more faithful than larger crabs). In Mar Chiquita, a higher proportion of fidelity previous to flooding and a size-dependent response to flooding were detected, suggesting that fidelity may be modulated by tides having different effects on crabs with different body sizes. Equal proportions of males and females displaying site fidelity were observed at all study zones and sites. Our study suggests that N. granulata burrow fidelity behaviour changes with latitude and landscape (mudflat or saltmarsh) and can be sensitive to variables such as body size and frequency of flooding. Fil: Nuñez, Jesus Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ribeiro, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ocampo, Emiliano Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Luppi, Tomas Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Land-sea interface is an ecotone where the intersection of marine and terrestrial ecosystems create unique ecological conditions for terrestrial mobile species and freshwater-adapted organisms to exploit marine-derived food resources. Mammalian carnivores play an important role in almost any ecosystem where they live due to theirtop-down (or trophic cascade) effects on prey species and primary producers, thus structuring ecosystems along varied food-web pathways. We use camera trapping tostudy the patterns of coexistence, habitat use and activity pattern of carnivores speciesin a coastal area in southern Buenos Aires province, Argentina. We were able to detectfive of the seven species of Mammalian carnivores being the Pampas fox Lycalopexgymnocercus and Geoffroy´s cat Leopardus geoffroyi the two most common.Geoffroy´s cat seems to use more intensively those areas close to the shoreline, whilewe found little support of it for Pampas fox; which seems to use more inland areas.Congruently, we found evidence of a lack of spatial and, to a lower extent, temporalavoidance between the two most common carnivore species of our study area. Ourfindings support those previous studies indicating that the coastal dunes have animportant role in the conservation of the biodiversity of Buenos Aires province. Wildlifeconservation is compatible with carefully-designed ecotourism and limitedinfrastructure development and this may be a unique chance for the areas of BuenosAires coast that have not been affected yet by poorly planned, conservation-unfriendlyurbanization. Fil: Caruso, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Luengos Vidal, Estela Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Manfredi, Matilde Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Araujo, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Lucherini, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Casanave, Emma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina

A histological survey of the commercially edible mussels Mytilus platensis and M. chilensis from wild and cultivated populations along the coast of Patagonia, Argentina (42°00’ to 54°47’S), was carried out to determine their health status. Diagnostic results included 3 types of inflammatory responses (infiltrative, nodular, and encapsulation), disseminated neoplasia disease, 2 abnormal reproductive conditions (gonadal atresia and intersex), prokaryotic inclusions, protozoans, and metazoans. Pathogen prevalence and infection intensity among mussels of different sampling sites and between those of wild and cultivated populations were compared. Inflammatory responses were recorded in all mussels from all sites, while disseminated neoplasia only occurred in the most southern cultivated M. chilensis. Intracellular prokaryotic inclusions were broadly distributed in the mussels from both northern and southern Patagonian coasts. Ciliates showed the highest prevalence among wild mussels from the colder waters of Bahía Brown. Turbellaria were recorded at higher prevalence in cultured mussels (41.7%), and trematode metacercariae occurred exclusively in intertidal wild mussels. None of the parasites found appears to be a problem to the fishery or farming, although disseminated neoplasia should be monitored. In addition, we found that mytilid species coexisting with M. platensis (Aulacomya atra and Perumytilus purpuratus) at one location shared the same pathological conditions and parasites, which differed from those of M. platensis at a distant locality. These results suggest that pathological conditions and parasites were influenced more by ecological habitat factors than by the species of mussels present, based on similar parasite assemblages found among closely related mytilid hosts in the same geographical area. Fil: Vázquez, Nuria Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Cremonte, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Frizzera, Antonella Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina

Pseudopercis semifasciata is a demersal teleostean fish, endemic of the southwest Atlantic Ocean, inhabiting coastal waters from 23° S to 47° S. The present study has the purpose to analyse for the first time the maturitycycle and the reproductive effort of this species from samples collected in waters off Buenos Aires Province (Argentina).The evolution of the gonadosomatic index (GSI) and the pattern of gonad development showed that spawning in P. semifasciata occurs during the austral spring and early summer, with a main peak in November. Length at first maturity, estimated only for females, was 31.77 cm TL, and age at first maturity was 2.38 years.Batch fecundity was very low, ranging between 20,647 and 152,070 hydrated oocytes, and showed significantpositive relationships with total length, total weight and age. In contrast, relative fecundity (27 hydrated oocytes/g ± 12 hydrated oocytes/g) showed an opposite pattern: it decreased with total length, total weight, age and condition. The low fecundity values estimated for P. semifasciata, together with its low growth rate, make it necessary to consider these particular traits in the adoption of management strategies for sandperch fisheries, in order to preserve local populations of this species. Fil: López, S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Macchi, Gustavo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Militelli, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina

Long-finned pilot whales (Globicephala melas) are among the few odontocetes that show an anti-tropical distribution. The North Atlantic subspecies (G. m. melas, Traill 1809) has been widely studied in the east and west coast, but there is little previous information on the Southern subspecies (G. m. edwardii, A. Smith 1834). Here we investigated the skull morphometry of both populations, subspecies status nowadays, with the aim of characterizing and comparing them. We examined a total of 93 adult skulls. In all skulls, 21 measurements were analyzed. Our results clearly differentiated skull morphology between long-finned pilot whale subspecies, being the following characters the most important in the discrimination: width of rostrum at base, and at ¼, ½ and ¾ length, length of rostrum to internal and external nares, and length and height of temporal fossa. Overall, G. m. edwardii specimens showed a longer skull, larger rostrum, wider nares, larger temporal fossa and longer orbits than G. m. melas. We suggest that these strong dissimilarities might have functional implications for feeding habits, diving behaviour and sound production capabilities. This is the first study that proves that skull morphometry in long-finned pilot whale subspecies presents significant differences. Fil: Marina, Tomas Ignacio. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina. Universidad Nacional de General Sarmiento; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Marchesi, María Constanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Prosser Goodall, Rae Natalie. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina

The abundance of certain spionid speciescan be closely linked to environmental disturbancesproducing quantifiable changes in community structure.We hypothesize that in stress conditions, thespionids would tend to localize in the upper level ofthe sedimentary column near to the sediment?waterinterface. The aim of this work was to analyze, throughan ex situ experiment, the effect produced by twoconcentrations of crude oil on the spionids at differentdepths of the sedimentary column and identifypossible pollution indicators. A simulated oil spill attwo input levels was carried out in the laboratory for30 days. The effect of the adding of crude oil wassignificant only in the superior level of the sedimentarycolumn. The differences in the abundancebetween levels by experimental conditions weresignificant in all the cases. Sensitive species likeScolelepis (Parascolelepis) sp. and Rhynchospio glutaeadisappeared while other species like Boccardiaproboscidea had a higher resistance to the addition ofcrude oil. This study constitutes the first characterizationof spionid assemblages of the Patagonian coastsaltered by crude oil in sediments, and the firstidentification of species, which can be useful pollutionindicators. Fil: Ferrando, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Grupo de Investigación y Desarrollo Tecnologico En Acuicultura y Pesca. - Universidad Tecnologica Nacional. Facultad Regional Chubut. Grupo de Investigacion y Desarrollo Tecnologico En Acuicultura y Pesca.; Argentina Fil: Diez, María Emilia. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Puerto Madryn. Instituto Patagonico del Mar.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Pastor, Catalina Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina Fil: Luis, Esteves José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina

The presence of epizoic diatoms on the skin of a variety of large marine vertebrates, such as whales and dolphins, has been often reported in the scientific literature. The first observations of an algal growth over on the skin of cetaceans were probably made around 1920. Later studies showed the presence of a new species, Cocconeis ceticola, on skin samples. Morphological features of this species led to the transference of C. ceticola, together with related forms, to the new genus Bennettella Holmes. Here, we report the occurrence of a diatom film of Bennettella ceticola on the skin of the Franciscana dolphin (Pontoporia blainvillei), obtained from bycatch in fishermen’s gillnets at Samborombon Bay, Argentina, in April 2005. For comparison the holotype of B. ceticola, deposited in the Natural History Museum (London, U.K.) dated 1920 and labelled as Cocconeis ceticola was examined. Detailed analysis of the fine structure of B. ceticola shows that it mostly matches the original description. However, the external raphe ending is not bifurcated (as originally described), and has only one simple, parallel sided slit and polar fissures hidden by a triangular flange. The triangular flange is the main diagnostic feature distinguishing Bennettella from Epipellis Holmes and Cocconeis Ehrenberg, allowing us to propose an emended description of Bennettella. The taxonomic affinities of B. ceticola with related genera, such as Cocconeis and Epipellis, are discussed. The present study constitutes the first report of B. ceticola as an epizoic diatom of a cetacean species in waters of the Argentinean Sea. Fil: Ferrario, Martha Elba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina Fil: Cefarelli, Adrián Oscar. Universidad Nacional de la Patagonia "San Juan Bosco". Instituto de Desarrollo Costero; Argentina. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina Fil: Fazio, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Bordino, Pablo. Fundación Aquamarina; Argentina Fil: Romero, Oscar Eduardo. Universitat Bremen; Alemania

Sarcothalia crispata is a carrageenophytic red alga from South America. The gametophytes produce kappa/iota carrageenan and the tetrasporophytes, lambda carrageenan, each with different properties and uses. The aims of this study were to determine the most effective method for obtaining S. crispata carpospores and tetraspores from southern Argentina, to evaluate the germination process of these spores, and to assess their survival and growth on different substrates. Desiccation, osmotic shock, low temperature, and spontaneous discharge were tested in the laboratory as spore release methods. The settlement and growth of sporelings were assessed on glass, ropes, shells, and gravel. No differences were found among induction methods, obtaining a higher output of tetraspores per frond area than of carpospores. After 3 months, shells and gravel showed the highest densities of carposporelings and tetrasporelings, while the lowest were observed on ropes and glass, respectively. Carposporeling survival varied between 88% on gravel and 13% on ropes; for tetrasporelings, mean survival was 5%. Sporelings attained the largest basal discs and longest erect portions on glass, and the smallest and shortest ones on ropes, those on shells and gravel being of intermediate in size. Based on these results, it can be concluded that carpospores and tetraspores from S. crispata obtained by spontaneous discharge and inoculated on shells and gravel will result in good densities, allowing germlings to develop and grow. This is the first study on reproductive aspects of S. crispata from the southwestern Atlantic coast, presenting valuable information for reliably initiating specific spore cultures. Obtaining this specific raw material separately for the extraction of kappa/iota or lambda carrageenan would lead to a better management of the resource by the carrageenan industry. Fil: Hughes, Melanie Hebe. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Michetti, Karina Mariel. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina

The potential for using suspended mesh-bags for larval/juvenile southern king crab (Lithodes santolla) aquaculture was assessed. Three early stages (Zoea, Megalopa and first juvenile, or C1) were confined for 45–65 days in mesh-bags near the sea-bottom. As L. santolla starts feeding when it reaches the first juvenile stage, the effect of biofouling presence was also tested in the C1 culture. Extreme vulnerability of the first larval stage was observed, as no live larvae were recovered when Z1 were used as seeds. On the other hand, survival of Megalopa and C1 reached 19.76 ± 1.08 and 30.00 ± 3.50%, respectively, and both C1 juvenile survival and growth were enhanced significantly by the presence of biofouling on the bags. These results indicate that suspended mesh-bags have potential for L. santolla juvenile culture in the sea. We suggest a 2-step culture process: indoor culturing of the three Zoea stages, and subsequently sea culture starting at the Megalopa stage. Once Megalopa molt to the C1 stage in the field, the already fouled culture system (mesh-bags) would allow newly molted crabs to feed. Further research should be directed towards sea culture optimization, including feeding requirements for bigger crabs, to implement a future stock enhancement program for king crabs in the Beagle Channel. Fil: Sotelano, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Di Salvatore, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Florentin, Olga Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Giamportone, Ariel Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Tapella, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

PAHs are persistent pollutants released into the environment by fossil fuels burning and leak during petroleum operations. Associated with suspended particles upon entering marine ecosystem are accumulated by benthic fauna. Human exposure occurs mainly from ingestion such as gastropods consumption. The objective was to determine PAHs in sediments and in the marine gastropod Buccinanops globulosus in sites with different maritime and urban influences. In sampling sites located 20 km from the harbor, PAHs were non-detected; while in harbor gastropods, the level of PAH4 was exceeded according to international normative. Level of dibenzo[a,h]anthracene in sediments was between the ISQG and PEL. Since these are the first results of PAHs in edible gastropods in South America, we concluded that PAHs can be dangerous for consumers according to ingestion frequency. Integrative studies are necessary to evaluate the interaction among pollutants in maritime areas and the incidence in human health due to shellfish consumption. Fil: Primost, Monica Angelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Tecnológica Nacional; Argentina Fil: Commendatore, Marta Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Torres, Pablo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina Fil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

The Argentine hake Merluccius hubbsi represents the dominant demersal fish and one of the main fisheries in the Argentine Sea. We analyzed over 17 years (September 1997–February 2015) of satellite surface chlorophyll concentration (CHL) and sea surface temperature anomaly (SSTA) data in the main spawning (SUB) and nursery (SJG) areas of the Patagonian stock of M. hubbsi. The variability observed in these environmental conditions was related to interannual differences in the reproductive success of hake. CHL values were maximum during austral spring (October–November) and minimum during winter (June–August). Blooms started in late September and lasted on average 128 and 110 days at SUB and SJG, respectively. At SUB, average CHL at the time of reproduction, the day of occurrence of the maximum chlorophyll concentration, and fall SST anomalies were significantly related to recruitment (RVPA) a year later and to two Larval Survival Indices (LSISSB and LSITEP) considered. At SJG, RVPA, LSISSB, and LSITEP showed negative correlations with fall (March–May) SSTA. Total egg production was not related to fall SSTA or spring phytoplankton dynamics at SUB or SJG. Significant positive trends were observed in the time series of CHL and SSTA in the study area. The trends observed in CHL represent average increases of 40.7% and 35.7% since 1997 at SUB and SJG, respectively. The potential implications of long-term changes in environmental conditions for hake reproductive success are discussed. Fil: Marrari, Marina. Universidad de Buenos Aires; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Macchi, Gustavo Javier. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Santos, Betina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Leonarduzzi, Ezequiel. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina

In South America, the order Atheriniformes includes the monophyletic genus Odontesthes with 20 species that inhabit freshwater, estuarine and coastal environments. Pejerrey Odontesthes argentinensis is widely distributed in coastal and estuarine areas of the Atlantic Ocean and is known to foray into estuaries of river systems, particularly in conditions of elevated salinity. However, to our knowledge, a landlocked self‐sustaining population has never been recorded. In this study, we examined the pejerrey population of Salada de Pedro Luro Lake (south‐east of Buenos Aires Province, Argentina) to clarify its taxonomic identity. An integrative taxonomic analysis based on traditional meristic, landmark‐based morphometrics and genetic techniques suggests that the Salada de Pedro Luro pejerrey population represents a novel case of physiological and morphological adaptation of a marine pejerrey species to a landlocked environment and emphasises the environmental plasticity of this group of fishes Fil: Colautti, Dario César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: González Castro, M.. Universidad Nacional de Mar del Plata; Argentina Fil: Villanova, Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Strüssmann, Carlos A.. Tokyo University Of Marine Science And Technology; Japón Fil: Mancini, Miguel Alberto. Universidad Nacional de Río Cuarto; Argentina Fil: Maiztegui, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Berasain, Gustavo. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios; Argentina Fil: Hattori, Ricardo Shohei. Tokyo University of Marine Science and Technology; Japón Fil: Grosman, Manuel Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina Fil: Sanzano, Pablo Miguel. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina Fil: Lozano, I.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Llamazares Vegh, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Salinas, V.. Universidad Nacional de Río Cuarto; Argentina Fil: Del Ponti, O.. Universidad Nacional de La Pampa; Argentina Fil: Fresno, P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Minotti, Priscilla Gail. Universidad Nacional de San Martín; Argentina Fil: Yamamoto, Y.. Tokyo University Of Marine Science And Technology; Japón Fil: Baigún, C.. Universidad Nacional de San Martín; Argentina

Gelatinous plankton is an important food resource for several species of fishes in theSouthwestern Atlantic Ocean. Some fish depend heavily on these organisms and arespecialized to feed on ctenophores, salps and medusae, while others only consumegelatinous plankton occasionally. We hypothesize that consumption of gelatinous planktonby fishes represents an alternative food resource when primary prey are not available duringcold periods in the study area. To determine seasonal variations of gelatinous planktonconsumption by fishes, data samples were grouped into cold and warm periods. A total of64,567 stomachs belonging to 106 species of fish were analysed, of which 32,943 (51%)contained food items. Of those containing food items, 2719 (8.2%), from 38 fish species,contained gelatinous items. Fourteen species ingested gelatinous in warm period, nine incold period, and 15 in both periods. The proportion of stomachs with gelatinous wassignificantly greater during the cold period. Ctenophores were the most predominant prey inboth periods, followed by salps and medusae. Consumption of ctenophores, salps andmedusae was unevenly distributed within the area during the different periods. Classificationmethods (group average sorting utilizing Bray?Curtis similarity measures based on log (X + 1)identified eight areas of consumption. SIMPER (similarity percentages) analyses revealed thatnine fish species contributed most to gelatinous plankton consumption. The seasonal andspatial variation of gelatinous consumption by fish would be related to the availability offood in each period. Strategies of gelatinous consumption, including survival, feedingopportunities and prey specialization, are discussed. Fil: Diaz Briz, Luciana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Sanchez, Mariela Felisa. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Marí, Noemí. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

We studied the abundance, size and growth rates of Engraulis anchoita larvae during the end of the species’ spawning season in relation to environmental variables. Two sampling transects, one in Península Valdés (northern transect: NT) and the other in Isla Escondida (southern transect: ST), with four stations each, were established in late summer. Both locations are characterized by high concentrations of E. anchoita larvae in spring, strongly associated with the presence of frontal waters, at the beginning of the species’ spawning season. Zooplankton and ichthyoplankton were sampled, and temperature profiles and chlorophyll-a satellite images were analyzed for each sampling station. Zooplankton samples were divided in size fractions, and composition and abundances were estimated. Standard length (SL), ontogenetic stages, and abundance (including eggs) were estimated. Additionally, age and growth rates were determined by otolith analysis. Two different scenarios were observed in both transects. In the NT, a frontal structure was found, while at the ST, the water column was completely homogeneous. Total zooplankton abundance was maximum at frontal waters, with 22,195 ind. m−3, being the small size fraction (

In this paper, we aim to provide optimal parameters for micro-computed tomography scans of fish otoliths. We tested fifteen different combinations to sagittae. The images were scaled to Hounsfield units, and segmented in two distinct volumes-of-interest (external and internal). The strategy we applied, for identifying optimum scan settings for otoliths, included analyses of the sinogram, the distribution of the Hounsfield units and the signal-to-noise ratio. Based on these tests, the optimum sets of parameters for the acquisition of tomographic images of sagittal otoilths were 80 kV, 220 μA, and 0.5 mm aluminum filter. The method allowed 3D shape analysis, internal and external density distribution, layer-by-layer density segmentation, and a potential objective method to count growth rings in otoliths. It was possible to compare mean densities between species, and we observed a significant difference among them. In addition, there are ontogenic changes, which could be increasing or decreasing the density. In this study, we applied tomography for several otolith analysis, that could be of great interest for future studies in diverse areas that use otoliths as the basic structure of analysis, or represents a new research line called eco-densitometry of otoliths, where tomography could be applied to explore the density within an ecological perspective. Fil: Vasconcelos Filho, Jonas. Universidad Federal Rural Pernambuco; Brasil Fil: Thomsen, Felix Sebastian Leo. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina Fil: Stosic, Borko. Universidad Federal Rural Pernambuco; Brasil Fil: Antonino, Antonio C. D.. Universidad Federal Rural Pernambuco; Brasil Fil: Duarte, Daniel A.. Universidad Federal Rural Pernambuco; Brasil Fil: Heck, Richard J.. University of Guelph; Canadá Fil: Lessa, Rosangela P. T.. Universidad Federal Rural Pernambuco; Brasil Fil: Santana, Francisco M.. Universidad Federal Rural Pernambuco; Brasil Fil: Ferreira, Beatrice P.. Universidad Federal Rural Pernambuco; Brasil Fil: Duarte Neto, Paulo J.. Universidad Federal Rural Pernambuco; Brasil

Predation is one of the main structuring forces in rocky intertidal communities, though with an effect depending on the environmental context and conditions. On the stressful Patagonia shores of Argentina, experimental studies concluded that predation does not play a significant ecological role. In the biogeographic transition zone of northern Patagonia, where medium-sized predators (like octopuses and sea stars) coexist and are relatively abundant, the effect of predators in the rocky intertidal zone was never tested. The present study evaluated the effect of two intertidal predators, the small octopus Octopus tehuelchus (d’Orbigny, 1834) and the sea star Anasterias antarctica (Lütken, 1857), on the abundance of prey and the interaction strength of these predators on different functional groups in a mid-intertidal rocky community of northern Patagonia. To do so, we conducted a short-term-exclusion experiment in the mid-intertidal area and estimated the interaction strength through dynamic indices. Our experimental exclusion of octopuses and sea stars had no positive effect on the abundance of prey in a short-term period, adding evidence that predation remains weak even in north Patagonia (i.e., under ameliorated physical stress), even with a relatively high abundance of predators. The combined interaction strength of those consumers on prey in the different functional groups was weak, with the dynamic indices being positive for mobile grazers and scavengers and negative for sessile filter feeders. These results emphasize the significance and deepen the understanding of the role of consumers, food web linkages, and community function in the biogeographic transition zone of north Patagonia. Fil: Storero, Lorena Pia. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Ocampo Reinaldo, Matías. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Narvarte, Maite Andrea. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Water quality was monitored along an Andean river of global importance using the freshwater bivalve Diplodon chilensis as sentinel species. Bivalves were placed in cages at three sites (S1-3) in the Chimehuin river in order to evaluate the long-term effects of a trout hatchery (S2), and the open dump and sewage treatment plant of a nearby city (S3). Water samples and bivalves were collected at 0 (September 2011), 3 (December 2011), 6 (March 2012), 9 (July 2012), and 12 (September 2012) months, from S3, S2 and from a reference site upstream (S1), and physicochemical parameters and the biological response of the caged bivalves were studied. ROS production, antioxidant response, oxidative damage, energy status and morphometric ratios were included as response biomarkers. Most of biomarkers showed site-and time dependence including bivalves transplanted at S1, revealing natural variability. Both anthropogenic perturbed sites (S2 and S3) showed differences in the exposed-bivalves with respect to the reference site (S1) in their biomarker responses after 9 and 12 months of exposure (July and September, respectively). Multivariate analysis showed alterations in hemocytes (ROS, TOSC and NRRT50), energy balance in digestive gland (energy and DGF), and in the detoxification response (GST) and GSH values in gill when bivalves were exposed to hatchery waste; whereas metal and bacterial pollution (S3 in July) caused GSH increase and a reduction of lysosomal damage in hemocytes. Results show that changes in the water quality of Chimehuin river due to the anthropogenic impact can be detected using the biomarkers analyzed on D. chilensis, being a useful tool for studies of long-term monitories. Fil: Yusseppone, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Bianchi, Virginia Angélica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Castro, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Luquet, Carlos Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Sabatini, Sebastian Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Rios, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Rocchetta, Iara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Made available in DSpace on 2018-11-26T17:54:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fiddler crabs are known as ecosystem engineers as well as important connectors of energy flow between the intertidal zone and the adjacent marine and terrestrial environments, being predated by both marine and terrestrial species. Studies on their activity patterns are critical to understand their overall role in the function of estuarine ecosystems. Recent studies have found that fiddler crabs, which are active at low tide, are the main food item of fishes hunting at high tide in the intertidal zone, suggesting that some species could also be active at high tide. We assessed the activity patterns of two fiddler crabs, Leptuca leptodactyla (Rathbun, 1898) and L. thayeri (Rathbun, 1900) using pitfall traps deployed at different diurnal and tidal conditions at two southeast Brazilian estuaries. Our data shows that L. leptodactyla was mostly active at low tide during both day and night, whereas L. thayeri was active at low and high tide, a behavior uncommonly reported for fiddler crabs. Our results also confirm that some fiddler crabs can have a previously unreported importance as food for aquatic predators. Univ Estadual Paulista Julio de Mesquita Filho UN, Inst Biociencias, Lab Ecol & Comportamento Anim, Campus Litoral Paulista, BR-11330900 Sao Vicente, SP, Brazil Univ Estadual Paulista Julio de Mesquita Filho UN, Inst Biociencias, Programa Posgrad Ciencias Biol Zool, BR-18618689 Botucatu, SP, Brazil UNLP, CONICET, Inst Limnol Dr Raul A Ringuelet, Boulevar 120 & 60, La Plata, Buenos Aires, Argentina Univ Aveiro, Ctr Environm & Marine Studies CESAM, Campus Univ Santiago, P-3810193 Aveiro, Portugal Univ Aveiro, Dept Biol, Campus Univ Santiago, P-3810193 Aveiro, Portugal Univ Hong Kong, Swire Inst Marine Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong, Sch Biol Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China Univ Firenze, Dipartimenio Biol, Via Madonna Piano 6, I-50019 Sesto Fiorentino, Italy Univ Estadual Paulista Julio de Mesquita Filho UN, Inst Biociencias, Lab Ecol & Comportamento Anim, Campus Litoral Paulista, BR-11330900 Sao Vicente, SP, Brazil Univ Estadual Paulista Julio de Mesquita Filho UN, Inst Biociencias, Programa Posgrad Ciencias Biol Zool, BR-18618689 Botucatu, SP, Brazil FAPESP: 2010/09763-9-TMC FAPESP: SC 2016/08687-3

Skates (Elasmobranchii, Rajiformes) are a morphologically conservative group of bentophagous chondrichthyan fishes with a high degree of endemism, that occur on marine soft bottoms. Subtle morphological aspects and bathymetric distribution are traits that vary among skate species that could have implications for their feeding ecology. We test how body size, snout length and bathymetric distribution influence the feeding habits and dietary niche breadth in skates using data on 71 species taken from the literature. We hypothesized that snout length has an effect on diet composition. We also hypothesized that dietary niche breadth increases with increasing depth range and decreases with increasing body size of skate species. Generalized additive models for location scale and shape were fitted with taxonomic level (genera nested within family) included as a random effect term in each model. A model selection approach to test the level of support for alternative models was applied. We found that skate species that forage on large prey have the largest body size and skate species with the smallest body size prey on small and medium-sized invertebrates. The results indicated that body size has an effect on feeding habits of skates, whereas an effect of snout length was not supported. Bathymetric variables have an effect on the diet of skates. Our prediction that dietary niche breadth increases with increasing depth range and decreases with increasing body size of skate species was supported in part: in a first phase the relationship between dietary niche breadth and body size is positive, then in a second phase, including species larger than 1000 mm total length, the relationship become negative. Fil: Barbini, Santiago Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Sabadin, David Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Lucifora, Luis Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina

We investigated the effects of ocean warming and glacial melting on phytoplankton assemblage composition and physiology in coastal Antarctica by exposing assemblages to a 4 °C increase in seawater temperature (T) and a 4 psu decrease in salinity (S) with respect to ambient values in a 6-day microcosm experiment. Seawater samples from Potter Cove in King George Island (Antarctica) were placed in outdoor microcosms and exposed to four treatments: ambient S-ambient T (S0T0, control), low S-ambient T (S-T0), ambient S-high T (S0T+), and low S-high T (S-T+). The relative abundance of unsaturated fatty acids (UFAs) 20:5ω3, 18:4ω3 and 16:1ω7 in relation to saturated FAs (14:0 and 16:0) significantly increased in all treatments at 24 h, compared to the control. At the same time, we detected a significant increase in the production of Thiobarbituric Acid Reactive Substances (TBARS), used as a proxy for lipid damage, in the S-T0 and the S0T+ treatments. In contrast, in S-T+, concentrations of TBARS remained significantly lower than in the control throughout the experiment. Although phytoplankton species composition did not change during the experiment, an increase in the relative abundance of diatoms (>20 μm) was found in all treatments compared to the control at 24 h, with no further changes during the rest of the experiment. Furthermore, the relative abundance of small diatoms (10–20 μm) increased only in S0T+, and small prasinophytes decreased at S-T+ at the end of the incubation period. Our results show a stable unsaturated to saturated FA ratio under the synergistic effects of high temperature and lower salinity, which may help protect phytoplankton cells from lipid damage. When phytoplankton assemblages were exposed to high temperature or low salinity, separately, the proportion of unsaturated FAs increased after 48 h. This increase in FAs resulted in greater lipid damage, which could be potentially avoided, as shown by previous studies, by antioxidant responses or changes in osmoregulatory proteins and FA synthesis by the activation or inactivation of desaturase enzymes. Variations in FA content due to changing environmental conditions can alter the quality of phytoplankton as a food source with potentially critical implications for the marine food web. Fil: Hernando, Marcelo Pablo. Comisión Nacional de Energía Atómica; Argentina Fil: Schloss, Irene Ruth. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentina Fil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina Fil: Malanga, Gabriela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina Fil: Varela, Diana E.. University of Victoria; Canadá Fil: De Troch, Marleen. University of Ghent; Bélgica

In this study, we reported the species composition and spatial distribution of Scyphomedusae and Cubomedusae from the southwestern Atlantic and Subantarctic region and reviewed the available knowledge of life history traits of these species. We gathered the literature records and presented new information collected from oceanographic and fishery surveys carried out between 1981 and 2017, encompassing an area of approximately 6,7 million km2 (32-60°S, 34-70°W). We confirmed the occurrence of 15 scyphozoans and 1 cubozoan species previously reported in the region. Lychnorhiza lucerna and Chrysaora lactea were the most numerous species, reaching the highest abundances/biomasses during summer/autumn period. Desmonema gaudichaudi, Chrysaora plocamia, and Periphylla periphylla were frequently observed in low abundances, reaching high numbers only occasionally. Phacellophora camtschatica, Aurelia sp., Drymonema gorgo, Atolla chuni, Stygiomedusa gigantea and Pelagia cf. noctiluca were observed always in low numbers. Atolla wyvillei, Stomolophus meleagris, Desmonema comatum and Tamoya haplonema were reported just a few times and mostly individually. Although new species/reports can be found as surveys are undertaken, these results are considered to be the reliable baseline for further ecological studies seeking to understand the ecological role that these jellyfish play in marine ecosystems. Fil: Schiariti, Agustin. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Dutto, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Pereyra, Daiana Yanel. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Siquier, Gabriela Failla. Universidad de la República; Uruguay. Universidad de la República. Facultad de Ciencias. Departamento de Biología Animal. Laboratorio de Zoología de Invertebrados ; Uruguay Fil: Morandini, André C.. Universidade de São Paulo. Instituto de Biociências. Departamento de Zoología; Brasil

This study aimed to assess the diel changes of ichthyoplankton occurrence, during a known recruitment period, to a wind-dominated coastal lagoon (Argentina). We collected plankton samples at three sites of the lagoon's inlet area every 3 h during four 24 h cycles in mid austral summer. For each early-life history stage (eggs, yolk sac, preflexion larvae, postflexion larvae and early juveniles), the relationship between the abundance and possible combinations of the time of sampling, the wind effect, the wave period and the tidal state was evaluated by fitting generalized linear mix-effects models (GLMM). The wind effects depending on the time of sampling mainly affected fish abundance in all developmental stages. Overall, the highest abundances were collected at nocturnal hours when low-speed offshore winds blew. In addition, higher abundances of eggs, yolk sac and preflexion larvae were related to the incoming flood tide; whereas higher abundances of postflexion larvae and early juveniles were related to longer wave periods. We argued that the daily variation in the abundance of early-life history stages of fishes is related to the sea-land breeze cycle. Therefore, a conceptual framework of the recruitment process of eggs, larvae and early juveniles of fishes into this estuarine system considering the daily effect of winds is proposed. Fil: Bruno, Daniel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; Argentina Fil: Delpiani, Sergio Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina

In the last decades, an increasing fishing effort and a decreasing trend in fish catches have been observed in southern Brazil. Considering that marine mammals and fisheries usually compete for the same resources, it is reasonable to presume that the feeding ecology of these predators is affected by the current scenario. To evaluate this hypothesis, long-term variation in the diet of the South American sea lion (Otaria flavescens) relative to fisheries exploitation was analyzed for two periods (1993–2003 versus 2004–2014). The degree of overlap between the relative biomass of the sea lions’ diet and the target species of six types of local fishery was analyzed. An increase in prey overlap between sea lions and fisheries was observed in the more recent sampling period, along with an increase in prey diversity, richness, and niche breadth of the sea lions’ diet. These results suggest that the overfishing scenario could partly explain the modified feeding ecology of the sea lions. In this context, we recommend a review and better regulation of the current fishing effort in the region, which we believe will be an important step to maintain the fish stocks and minimize the impact of fishing on marine top predators. Fil: Machado, Rodrigo. Universidade Federal do Rio Grande do Sul; Brasil Fil: Rosa de Oliveira, Larissa. Universidade Do Vale Do Rio Dos Sinos; ; Brasil Fil: Ott, Paulo Henrique. Universidade Estadual Do Rio Grande Do Sul; ; Brasil Fil: Denuncio, Pablo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Haimovici, Manuel. Universidade Federal do Rio Grande do Sul; Brasil Fil: Cardoso, Luis Gustavo. Universidade Federal do Rio Grande do Sul; Brasil Fil: Danilewicz, Daniel. Universidade Estadual de Santa Cruz; Brasil Fil: Moreno, Ignacio Benites. Universidade Federal do Rio Grande do Sul; Brasil Fil: Borges-Martins, Márcio. Universidade Federal do Rio Grande do Sul; Brasil

Physical, chemical and biological processes facilitate cross-habitat connections in lakes, prompting food webs to be supported by different subsidies. We tested the hypothesis that the pelagic food web is subsidized by littoral resources and fish foraging behaviour plays a major role in carbon flux and on food web structure in shallow hypereutrophic lakes. We performed a fish diet and carbon and nitrogen isotope analyses to predict the linkage between littoral and pelagic habitats in three shallow hypereutrophic lakes. Lakes differed in morphology, fetch, macrophyte composition and width of the littoral zone. δ13C signals of seston differed among lakes, but were similar to other producers. Macroinvertebrates and fish carbon signatures were more enriched in the lake co-dominated by emergent and submerged vegetation. Fish foraging behaviour indicates that more than the 80% of the carbon that sustain adult fish was channelled from the littoral. In conclusion, littoral carbon were relevant and sustain, in part, food web in these shallow lakes. Factors like the extension of the littoral zone, lake morphometry, and the dominance of multi-chain omnivorous fish facilitate the connection among lake compartments and the transference of littoral carbon to lake food web. Fil: Gonzalez Sagrario, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Rodríguez Golpe, Daniela Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: La Sala, L.. Universidad Nacional de Mar del Plata; Argentina Fil: Sanchez Vuichard, Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Minotti, Priscilla Gail. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. Laboratorio de Ecología, Teledetección y Ecoinformática; Argentina Fil: Panarello, Hector Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina

Due to strong seasonality and spatial variation in ecosystem productivity, fish can show ontogenetic and/or seasonal changes in habitat use and move between different habitats to exploit the richest food resources. Here, we evaluate the spatial patterns of the size distribution of Patagonian hoki Macruronus magellanicus in relation to the highly productive frontal systems of the southern Patagonian shelf. Additionally, we assessed diet composition in relation to size. Fish data came from 10 scientific cruises that were carried out between April 1978 and March 1979 during cold and warm seasons of the year. Samples were collected using demersal hauls that for the purposes of this study were ascribed to frontal or non-frontal zones. Based on the analysis of the total length of 3660 Patagonian hoki individuals, a generalized linear model was constructed to evaluate the association between fish size and fronts. Moreover, prey items consumed by fish grouped into 4 size classes were evaluated by analysing the contents of 1067 stomachs. Our results showed that smaller fish (juveniles) were more frequently located along frontal areas and preyed upon zooplankton. In contrast, larger fish (adults) preyed on larger items and showed no spatial relationship with fronts. The positive relationship observed between small-sized fish and fronts may be related to the low trophic level of these fish and the abundance of small-sized prey in frontal zones. Fil: Alemany, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina

The shallow sandy marine subtidal ecosystem off Mar del Plata, Argentina, is the scene of multiple fisheries activities, in particular the prawn-shrimp Artemesia longinaris and Pleoticus muelleri grounds. We examined the δ 13 C vs δ 15 N isotope signatures of 22 species commonly found in the area in order to understand how this ecosystem supports the fishery, with special emphasis on imposex-Affected gastropod populations. Our results indicate that the main food source for Olivancillaria urceus and Buccinanops monilifer were bivalves and crustaceans. Buccinanops duartei and Olivancillaria carcellesi feed on bivalves and also on macroalgae. These findings indicate, for the first time, a slight selectivity of some of the gastropods studied for local drifted algal sources and how gastropods may scavenge available food from by-catch returned to the sea. The fishes Urophysis brasiliensis and Callorhynchus callorhynchus appeared to be the top predators of this area with B. duartei and O. carcellesi constituting important components of their diet. Fil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Brey, T.. Alfred Wegener Institute for Polar and Marine Research; Alemania Fil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

In the present study, we analyzed the influence of untreated sewage exposure on carbon (δ13C) and nitrogen (δ15N) isotopic composition and several biochemical responses in the barnacle Balanus glandula. The main objective was to evaluate whether changes in stable isotopes signature do reflect biochemical sub-lethal effects in a sewage influence gradient. Stable isotopes analysis showed differences in isotope signatures between close sewage influence and distant sites, being δ13C signatures stronger than that of δ15N. Regarding biochemical effects, although organisms close to the effluent would be clearly exposed to contaminants (increased GST activity) the oxidative stress would not be too evident (peroxidases and ACAP not affected). The most affected physiological aspect was the digestive one, reflected in increased alkaline proteases and lipases activities. A clear relation between δ15N and GST activity was found, showing to δ15N as an indicator of potential exposure to chemical contaminants. Fil: Laitano, Marìa Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Diaz Jaramillo, Mauricio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Rodriguez, Yamila Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ducos, Estela Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina Fil: Panarello, Hector Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina Fil: Fernandez Gimenez, Analia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The limpet Siphonaria lessonii is very common along Atlantic Patagonian intertidal rocky shores. We studied the early intracapsular embryonic development of this limpet in detail in two populations in north Patagonia, with different environmental conditions (i.e. wave exposure, wind, temperature). Early development in both populations was achieved at controlled and equal conditions (13°C). The spawn consisted of a series of enchained egg capsules embedded in a jelly mass. The development from egg to hatching veliger took 9–11 days in embryos from both populations. The developmental process at both sites was identical, differing only in the embryos' sizes at each stage. Larger adult individuals producing larger embryos were registered at the sheltered site. The differences in sizes of adult and embryos of S. lessonii could be attributed to distinct environmental stressful conditions between sites. Fil: Zabala, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Averbuj, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

The recently established diatom genus Shionodiscus is characterized as possessing a labiate process on the valve face and strutted processes with long internal and reduced, or no, external extensions. Many Thalassiosira species with these features were transferred to this new genus, as well as some with short internal, strutted process extensions. Examination of samples from the Argentine continental shelf and slope waters, and from the Beagle Channel, revealed the presence of a small centric diatom that formed an extensive bloom in slope waters during spring 2005 and 2006. Analysis by light and electron microscopy revealed high similarity to specimens previously referred as Thalassiosira bioculata var. raripora. This name was never effectively published; nevertheless, the name has been adopted and observations referring to it have been reported on several occasions. Here we trace the usage of the (nomenclaturally invalid) name Thalassiosira bioculata var. raripora in the literature, and formally describe the species as Shionodiscus gaarderae, based on our observations and comparison with previous reports. A morphological comparison of this and similar taxa is also provided. In addition, we offer an emended description of S. bioculatus var. bioculatus from Ostenfeld material sampled from the ‘Färöer Island Naströ Fjord Plankton (16.9.1902)’, held in the Hustedt collection. Finally, we propose the transfer of Thalassiosira rosulata to Shionodiscus. Fil: Ferrario, Martha Elba. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina Fil: Cefarelli, Adrián Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Instituto de Desarrollo Costero; Argentina Fil: Beszteri, Bank. Helmholtz-Zentrum für Polar- und Meeresforschung. Alfred-Wegener-Institut; Alemania Fil: Akselman Cardella, Rut. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Fabro Cerreia Fus, Elena Ines. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Cembella, Allan. Helmholtz-Zentrum für Polar- und Meeresforschung. Alfred-Wegener-Institut; Alemania

Here, we provide the first list of shallowwater hydroids for Alacranes Reef, Mexico, comprising 49 species in 33 genera. The most speciose superorder was Leptothecata (36 species), with three particularly diverse families: Clytiidae, Sertulariidae, and Plumulariidae. Three species were recorded for the first time in the Gulf of Mexico (GoM), and 13 for the south-central GoM. The majority of fauna was substrate generalist with specific distributions: 38 hydroid species occurred on natural reefs, 18 on artificial reefs, 9 on drifting Sargassum spp., and 8 on the seagrass Thalassia testudinum K.D. Koenig. Our results significantly increase knowledge of the hydroids from Mexican waters. This is an important step toward detecting non-native species in the near future, as well as for improving and designing new conservation programs in the area. Fil: Mendoza Becerril, María A.. Centro de Investigaciones Biologicas del Noroeste; México Fil: Simões, Nuno. Universidad Nacional Autónoma de Puerto de Abrigo; México Fil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The stress gradient hypothesis states that positive interactions become more important as physical stress increases. Organisms living in Patagonian intertidal ecosystems are subjected to high desiccation stress due to elevated temperatures and strong winds. In coastal environments, sponges and macroalgae are common benthic organisms, and they occur from the subtidal to intertidal zones. As human pressure has increased in these systems, both sponges and macroalgae have become more abundant, which has led to more frequent interactions between them. To evaluate the interaction between Hymeniacidon perlevis and Ulva lactuca in 2 contrasting environments, we sampled their abundance and conducted field factorial experiments consisting of sponge transplants and manipulation of algal presence. Our results show that in harsher environments, U. lactuca facilitates H. perlevis likely through the reduction of direct solar radiation or high substrate temperature beneath its canopy, whereas in milder environments, U. lactuca negatively affects H. perlevis throughout other physical or chemical mechanisms (e.g. abrasion, feeding interference through changing current dynamics, depletion of oxygen, allelochemical compound production). Fil: Gastaldi, Marianela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Firstater, Fausto Nahuel. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Narvarte, Maite Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina Fil: Daleo, Pedro. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Knowledge of growth patterns of an animal species is fundamental to understand their life history. This information is also used to help define population boundaries of threatened cetaceans, such as the Franciscana dolphin, Pontoporia blainvillei. A total of 108 Franciscana dolphins incidentally captured in artisanal fishing nets in estuarine and marine coastal waters of the northern part of the Franciscana Management Area IV (North FMA IV), Argentina, were studied. The objective of the present paper was to study age and growth parameters of Franciscanas from North FMA IV and to compare these parameters between estuarine and marine potential populations within this area. We used von Bertalanffy and Gompertz growth curves to model growth trajectories. The estimated asymptotic lengths demonstrated that Franciscana dolphins from this area were smaller (females: 136.3 cm and males, 122.1 cm) than southern FMA IV values previously published. They also showed the reverse sexual size dimorphism that is known across their range. However, the estimated asymptotic length was not statistically different between the estuarine and marine females within the study area. In spite of this, the fact that the northern forms of the FMA IV were smaller than the southern specimens supports the hypothesis of more than one population of the species within this management area. The North FMA IV has the highest reported mortality levels of Franciscana dolphins within the FMA IV; these results are relevant to the knowledge base of Franciscana dolphins in the region. Fil: Denuncio, Pablo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Negri, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Bastida, Ricardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Rodriguez, Diego Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

In this stu, dy of northern Patagonia in Argentina, we examined the annual cycle of the epiphyte composition and abundance on Ulva sp. with respect to intertidal elevation, season and position on host. We found spatial segregation in most environmental gradients. Local environmental conditions, intertidal levels, seasons and portion of host thalli had specific patterns of algal epiphytic community. The host population exhibited seasonality and differential morphological attributes according to the intertidal elevation. Thalli of Ulva sp. had the highest maximum diameters and were heavier in spring and summer at the upper elevation. Epiphytes were more abundant growing on host thalli at middle elevations. Epiphytic Dinophyceae, Chlorophyceae and Cyanophyceae presented clear seasonality. Epiphyte abundances were related to periods with high seawater temperature, long days and high radiation. Lyngbya sp., Cocconeis sp., Navicula spp., Rhabdonema arcuatum, Stylonema alsidii and Myrionema strangulans had the highest frequency. The highest epiphyte abundance was observed in holdfasts, with M. strangulans having the highest frequency and cover. These results are relevant to commercial aquaculture ventures for food and feed sources and application in bioremediation. Fil: Gauna, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Escobar, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Odorisio, Mariangeles. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Caceres, Eduardo Jorge. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina

The influence of nutrient availability and light conditions on phytoplankton size-structure, nutritional strategy and production was studied in a phosphorus-poor estuary in the northern Baltic Sea receiving humic-rich river water. The relative biomass of mixotrophic nanophytoplankton peaked in spring when heterotrophic bacterial production was high, while autotrophic microphytoplankton had their maximum in summer when primary production displayed highest values. Limiting substance (phosphorus) only showed small temporal variations, and the day light was at saturating levels all through the study period. We also investigated if the phytoplankton taxonomic richness influences the production. Structural equation modelling indicated that an increase of the taxonomic richness during the warm summer combined with slightly higher phosphorus concentration lead to increased resource use efficiency, which in turn caused higher phytoplankton biomass and primary production. Our results suggest that climate warming would lead to higher primary production in northerly shallow coastal areas, which are influenced by humic-rich river run-off from un-disturbed terrestrial systems. Fil: Paczkowska, Joanna Marianna. Universidad de Umea; Suecia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Umeå Marine Sciences Centre; Suecia Fil: Rowe, Owen F.. Universidad de Umea; Suecia. Umeå Marine Sciences Centre; Suecia. University of Helsinki; Finlandia. Helsinki Commission; Finlandia Fil: Figueroa, Daniela. Umeå Marine Sciences Centre; Suecia. Universidad de Umea; Suecia. Swedish Meteorological and Hydrological Institute; Suecia Fil: Andersson, Agneta. Umeå Marine Sciences Centre; Suecia. Universidad de Umea; Suecia

The southern king crab (SKC) Lithodes santolla has supported a profitable fishery in the San Jorge Gulf (SJG) and adjacent area, Argentina, since 2004. This fishery allows landings only of males larger than 110 mm carapace length. Since large-male-only harvests have had a detrimental effect on the egg production of other king crab populations, here, we compared the SKC fecundity before the start of the industrial fishery (1994–1996) with that of the fully harvested population (2014–2018), and analyzed the variation in fecundity related to fishery policies, to areas with different levels of fishing effort, and to different times of the fishing season. During 2014–2016, SKC fecundity was 25% lower than that during the pre-fishery period (1994–1996). However, fecundity in 2017–2018 was 11% lower than that during the pre-fishery period. Results also revealed that fecundity was greater in coastal areas (where an artisanal fleet operates) than in offshore areas (where the industrial fleet operates) and that it was similar throughout the fishing season. We concluded that: 1) SKC fecundity decreased after 10 years of fishing, 2) fishing during the mating period affected SKC fecundity, and 3) there is no significant egg loss during the fishing season. Recent changes in SKC fishery management, including the mandatory use of escape rings and the implementation of a closure during mating, seem to have had a positive effect on SKC fecundity. Fil: Varisco, Martin Alejandro. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina Fil: Colombo, Julia Soledad. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina Fil: Di Salvatore, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Balzi, Pamela Patricia. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; Argentina Fil: Bovcon, Nelson Darío. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Vinuesa, Julio Hector. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina

The aim of this study was to assess the effect of ultraviolet radiation (280–400 nm) on survival, concentration of photoprotective compounds and total antioxidant capacity of Pleoticus muelleri. Two experimental diets were prepared: control diet and other supplemented with Undaria pinnatifida extract (3 g/100 g diet), a brown seaweed rich in photoprotective compounds. Animals were exposed for 7 days to two radiation treatments: a) PAR (Photosynthetically Active Radiation: 400–700 nm) b) PAR + UVR: total radiation spectrum (UVR 280–400 nm + PAR), under controlled conditions (20 ± 0.8 °C, S = 33, pH = 7.5). Shrimp in UVR treatments without supplemented diet, showed the highest mortality (72%). Under UVR-stress, concentrations of UV absorbing compounds were highest in animals fed the diet supplemented with U. pinnatifida, while the carotenoid concentration decreased, and the total antioxidant activity was the highest. These results suggest that under in UVR-stress animals could bioaccumulate photoprotective compounds from a diet with added seaweed extract. Fil: Marcoval, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina Fil: Díaz, Ana Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina Fil: Espino, Maria Laura. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Arzoz, Natalia Soledad. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Velurtas, Susana María. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina Fil: Fenucci, Jorge Lino. Universidad Nacional de Mar del Plata. Facultad de Cs Exactas y Naturales. Dpto de Cs Marinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The Beagle Channel is a remote subantarctic environment where mussel aquaculture initiatives have existedsince the early 1990s. Here we analyze phytoplankton biomass and composition, and the occurrence of harmfulmicroalgae species and their toxins at three sites during the period 2015?2016. The occurrence of potentiallyharmful algae was observed throughout the study period, including toxigenic dinoflagellates such asAlexandrium catenella (Group I of the A. tamarense complex), A. ostenfeldii, Dinophysis acuminata, Gonyaulaxspinifera, Azadinium sp., and the diatoms Pseudo-nitzschia australis and P. fraudulenta. Toxic dinoflagellates weredetected in low densities whereas a Pseudo-nitzschia bloom was observed in late February. Isolates of A. catenellaand P. delicatissima sensu stricto were phylogenetically characterized. The toxin profile of A. catenella wasdominated by GTX4, while P. delicatissima sensu stricto showed no production of the neurotoxin domoic acid inculture conditions. The results provide base-line information for the management of harmful algal blooms in thislittle explored subantarctic area. Fil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina Fil: Cefarelli, Adrián Oscar. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz | Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz | Universidad Nacional de la Patagonia "san Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Instituto de Desarrollo Costero; Argentina Fil: Diodato, Soledad Lorena. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Montoya, Nora Gladys. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Benavides, Hugo R.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Carignan, Mario Osvaldo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Hernando, Marcelo Pablo. Comisión Nacional de Energía Atómica; Argentina Fil: Fabro Cerreia Fus, Elena Ines. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Metfies, Katja. Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung; Alemania Fil: Lundholm, Nina. Universidad de Copenhagen; Dinamarca Fil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Álvarez, Marcela. Instituto Nacional de Investigaciones y Desarrollo Pesquero. Dirección de Pesquerías Demersales. Programa Pesquerías de Peces Demersales Costeros; Argentina Fil: Ferrario, Martha Elba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina

Common carp (Cyprinus carpio) is a global invader that exhibits a wide distribution in Argentina, particularly in shallow lakes and wetlands of the Pampean region. The hydrological conditions of these environments are driven by variations in annual precipitation that determine inter annual changes in water levels leading to flood-drought cycles. The present study focused on understanding the C. carpio population responses to annual rainfall regime and long-term flood and drought events in the Ajó wetlands located in the east of the Pampean region. The results of a two-year biological sampling program showed that C. carpio feeding rate, reproduction, condition, and recruitment were associated with the hydrological cycle. Otolith derived age structure of the population and back-calculated recruitment strength revealed that extraordinary flooding events generated strong cohorts while dry years resulted in low recruitment. Its long-life span (maximum 14 years in Ajó) coupled with a high fecundity, and broad diet allows C. carpio to persist in refugia during dry years and capitalize on wet years when inundation of the floodplain enhances recruitment and facilitates spread. Management and control strategies for this invader should therefore incorporate hydrological variability by promoting intensive removal campaigns during dry years when populations are dominated by large fish confined in remnant water-bodies and, during wet years, carp harvest fisheries should be promoted to reduce population density when increased connectivity is likely to facilitate spread., Facultad de Ciencias Naturales y Museo, Instituto de Limnología "Dr. Raúl A. Ringuelet"

Among those factors that determine the success of a fish cohort, trophic interactions play a key role, especially during the larval and juvenile stages. The Argentine hake Merluccius hubbsi is the most abundant demersal fish in the southwestern Atlantic and also one of the main commercial resources for Argentina. By employing C and N stable isotope analysis, we evaluated M. hubbsi changes in trophic niche and trophic position throughout their early life from early larvae to juveniles 2+ (8−330 mm total length, TL) during their drift from the spawning to the nursery ground. We analyzed 121 individuals and 7 possible resources in different sectors as fish move from the spawning to the nursery ground in the coastal region of northern Argentine Patagonia. Our results show that Argentine hakes occupy different trophic niches during their ontogenetic development. While larval stages (8−34 mm TL) feed almost exclusively on copepods, larger juveniles showed shrimps as their main prey. Individuals between 35 and 89 mm TL showed the most generalist diet, with a mix of both pelagic and epibenthic prey. Therefore, our results indicate that the change from a planktonic to a demersal habitat (settlement), which is of paramount importance in the early life history of hakes, is a gradual process. Fil: Botto, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gaitán, Esteban Nicolás. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina