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The paraphyletic diatom genus Nitzschia comprises over 1000 morphologically distinct pennate taxa, known from the benthos and plankton of freshwater, brackish and marine environments. The principal diagnostic characters for delimitation of Nitzschia species include valve shape, the position and structure of the raphe, presence/absence and shape of the proximal raphe endings the shape of the terminal raphe fissures, areola structure, and specific morphometric features such as cell size, and stria and fibula density. In this study, we isolated 12 diatom strains into culture from samples collected at the surface or greater depths of the southeastern Adriatic Sea. Morphological analyses included LM, SEM and TEM observations, which, along with specific morphometric features, allowed us to distinguish three new Nitzschia species. These findings were congruent with the results of phylogenetic analyses performed on nuclear-encoded SSU (18S) rDNA and chloroplast-encoded rbcL and psbC genes. One of the new species (Nitzschia dalmatica sp. nov.) formed a lineage within a clade of Bacillariaceae containing members of the Nitzschia sect. Dubiae, which was sister to Psammodictyon. A second lineage was part of a novel clade that is significantly distinct from other Nitzschia species sequenced so far and includes Nitzschia adhaerens sp. nov. and N. cf. adhaerens. A further new species was found, Nitzschia inordinata sp. nov., which appeared as the sister group to the N. adhaerens clade and the conopeoid Nitzschia species in our phylogenetic trees. Our findings contribute to the overall diversity of genus Nitzschia, especially in identifying some deep branches within the Bacillariaceae, and highlight under-scoring of this genus in marine plankton.

The objective of this study was to determine, both quantitatively and qualitatively, the variability in the diet of the anchovy, Engraulis encrasicolus, during its spawning period. Samples were obtained from commercial purse seine catches (April 2014 – September 2016) from coastal and offshore fishing areas of different trophic states and zooplankton composition over the eastern Adriatic Sea. In general, decapod larvae comprise the main source of diet during the anchovies’ spawning period in terms of frequency and abundance, followed by calanoid copepods. The main copepod prey that was identified for anchovy along the eastern Adriatic coast was calanoid Temora stylifera, followed by Oncaeid copepods and Corycaeidae. Although no significant differences in diet composition regarding the anchovy’s size was observed, the contribution of copepods decreased in larger individuals, and were gradually substituted by large crustaceans - decapods, euphausiids, mysids and amphipods. However, a significant difference in prey composition between coastal and offshore areas was observed (global R=0.164, p, Cilj ovog rada bio je utvrditi kvantitativnu i kvalitativnu varijabilnost u prehrani brgljuna Engraulis encrasicolus tijekom mrijesta. Uzorci iz komercijalnih ulova plivaricom (travanj 2014 – rujan 2016), obuhvatili su ribolovna područja obalnog i otvorenog mora duž istočne obale Jadrana, različitog trofičkog stanja i sastava zooplanktona. Ličinke deseteronožaca općenito su glavni izvor hrane tijekom mrijesta brgljuna, a prate ih kalanoidni veslonošci. Unutar veslonožaca najzastupljenija je bila vrsta kalanoida Temora stylifera, a slijede veslonošci skupine Oncaea i porodica Corycaeidae. Premda nisu utvrđene značajne razlike u sastavu prehrane u odnosu na dužinu ribe, udio veslonožaca smanjio se porastom dužine brgljuna, a postupno su ih nadomještali veliki rakovi - deseteronošci, eufazidi, rašljonožci i rakušci. Međutim, uočena je značajna razlika u sastavu plijena između obalnog i otvorenog mora (globalni R = 0.164, p

The concentrations of polychlorinated biphenyl (PCB) congeners were examined in two fish species from the Izmir Bay. A total of 624 individuals of different fish samples were sampled by trawling from three regions in Izmir Bay between 2010 and 2013. The total levels of indicator PCBs in all samples varied LOD (limit of detection) to 34.3 ng g?1 (dry weight) in the study area. The highest concentrations of PCBs were found in Gulbahce for Mullus barbatus and Diplodus annularis in 2011 and 2010, respectively. PCB153 was the major contributed congener in both fish species during sampling periods. Principal component analysis (PCA) was performed to evaluate the correlation of the determined variables in fish species. According to PCA, the PCBs are not related with fish length. One-way ANOVA test indicated that significant temporal variations were generally detected for PCBs, while non-significant spatial variations were examined between sampling sites. Six PCB congeners were found as 0.59–6.64 ng g?1 (wet weight, wwt) and compared with iPCB6 limits of 75 ng g?1 (wwt) revealed by the Environmental Food Safety Authority. Accordingly, all fish species analyzed did not surpass the safe limits of iPCB6 suggested by EU. The estimated daily intake of 6 PCB congeners by the people were less than the tolerable daily intake (TDI, 10-ng kg?1 body weight day?1) recommended by WHO (2003), suggesting that this intake would not cause adverse effects to residents of Izmir. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature., The authors are grateful to Dr. L. Tolga Gonul for his helpful comments on statistical analyses and assessment of health risk. We gratefully thank ARGEFAR for analyses assistance. We also express our deep gratitude to the scientists and crew of the R/V K. Piri Reis for collecting fish samples during the cruises.

Background Microbial communities of wild animals are being increasingly investigated to provide information about the hosts’ biology and promote conservation. Loggerhead sea turtles (Caretta caretta) are a keystone species in marine ecosystems and are considered vulnerable in the IUCN Red List, which led to growing efforts in sea turtle conservation by rescue centers around the world. Understanding the microbial communities of sea turtles in the wild and how affected they are by captivity, is one of the stepping stones in improving the conservation efforts. Describing oral and cloacal microbiota of wild animals could shed light on the previously unknown aspects of sea turtle holobiont biology, ecology, and contribute to best practices for husbandry conditions. Results We describe the oral and cloacal microbiota of Mediterranean loggerhead sea turtles by 16S rRNA gene sequencing to compare the microbial communities of wild versus turtles in, or after, rehabilitation at the Adriatic Sea rescue centers and clinics. Our results show that the oral microbiota is more sensitive to environmental shifts than the cloacal microbiota, and that it does retain a portion of microbial taxa regardless of the shift from the wild and into rehabilitation. Additionally, Proteobacteria and Bacteroidetes dominated oral and cloacal microbiota, while Kiritimatiellaeota were abundant in cloacal samples. Unclassified reads were abundant in the aforementioned groups, which indicates high incidence of yet undiscovered bacteria of the marine reptile microbial communities. Conclusions We provide the first insights into the oral microbial communities of wild and rehabilitated loggerhead sea turtles, and establish a framework for quick and non-invasive sampling of oral and cloacal microbial communities, useful for the expansion of the sample collection in wild loggerhead sea turtles. Finally, our investigation of effects of captivity on the gut-associated microbial community provides a baseline for studying the impact of husbandry conditions on turtles’ health and survival upon their return to the wild.

Atlantic bonito, Sarda sarda, is one of the representatives of the Scombridae family in the Adriatic Sea. Larvae and juveniles have been found and described in the area, but no information has been published regarding adults spawning in the Adriatic Sea. To explore the strong possibility that Atlantic bonito are reproducing in the Adriatic Sea, 122 specimens of adult Atlantic bonito were collected from a purse seine net ‘palamidara’ over four seasons in 2017. The fork length of the analysed specimens varied from 37.5 to 60.8 cm, with a mean of 48.83 ± 5.59 cm, while total body weight varied between 742.68 and 3102.59 g, with a mean value of 1700.49 ± 543.82 g. Gonadosomatic index values showed an increasing trend from autumn (0.123 for males, 0.897 for females) until spring, while in the summer, they reached their maximum values (3.609 for males, 5.604 for females). This trend was also confirmed by histological and macroscopic analyses of gonads, which suggested that the Atlantic bonito spawning season is in the spring-summer in the Adriatic Sea. Hence, this confirms that this species is spawning in the Adriatic Sea.

Cyst abundance and identity are essential for understanding and predicting blooms, and for assessing the dispersal of toxic target dinoflagellate species by natural or human mediated ways, as with ballast waters. The aim of this study was to apply rapid, specific and sensitive qPCR assays to enumerate toxic dinoflagellate cysts in sediment samples collected from Adriatic harbours. The molecular standard curves of various target species allowed obtaining the rDNA copy number per cyst. The analytical sensitivity for specific standard curves was determined to be 2 or 10 rDNA copies per reaction. The abundance varied in the range of 1–747 dinoflagellate cysts g−1 dry weight. The assays showed greater sensitivity as compared to counts by light microscopy. This qPCR method revealed a powerful tool for the quantification of cysts from toxic dinoflagellate resting stages in sediment samples from Adriatic ports.

The zooplankton community was analyzed in ten Adriatic ports as part of the port biological baseline surveys carried out within the framework of the BALMAS project. We provide the first inventory of resident zooplankton taxa and five detected non-indigenous zooplankton species (NIS), and their spatial and seasonal distribution patterns. Copepoda and meroplankton larvae, particularly of Mollusca, dominated the zooplankton in all sampled ports. We recorded a total of 76 indigenous copepod species and five NIS, among which Parvocalanus crassirostris detected in Šibenik and Rijeka ports and Oithona davisae in Venice port, are new for the Adriatic. All detected NIS were widely distributed within the recipient ports. Co-occurrences of NIS were observed in the ports of Venice, Bari, Ancona and Trieste. The results are expected to contribute to the quality of practical monitoring of zooplankton NIS and facilitate the synchronization of efforts in creating NIS- related policies for the Adriatic sub-region.

The blue shark belongs to the group of the most widespread pelagic sharks in the world. It inhabits the pelagic zone of almost all warm and temperate seas and oceans. As it is one of the most abundant shark species, it is frequently caught in different types of fishing gear operated in the pelagic zone. This study provides the first data on the reproduction of this species in Montenegrin waters (in the Southeastern Adriatic Sea). Six newborn blue sharks were found during our field excursions. For three of them, detailed morphometric measurements are presented. Alongside the newborns, a gravid female was also recorded. The data was collected in the period from April to October 2017. According to the published literature and the data presented in this paper, species reproduction is likely to be seasonal. A review of the areas where the specimens were recorded was carried out in order to infer if the adult females choose them specifically as their parturition grounds., Pas modrulj pripada grupi najviše rasprostranjenih pelagičnih morskih pasa na svijetu. Obitava u pelagičnoj zoni gotovo svih umjerenih i toplih mora i oceana. Premda je jedan od najčešćih morskih pasa, često se lovi različitim ribolovnim alatima koji se koriste u pelagijalu. Ovim istraživanjem sakupljeni su prvi podaci o reprodukciji ove vrste u Crnoj Gori (Jugoistočni Jadran). Tijekom terenskih istraživanja, evidentirano je šest tek rođenih jedinki. Za tri jedinke, prikazane su detaljne morfo-metrijske mjere. Pored spomenutih jedinki, zabilježena je i gravidna ženka ove vrste. Svi podaci su sakupljeni u razdoblju od travnja do listopada 2017. Prema do sada objavljenoj literaturi i ovdje prikazanim podacima, moguće je da je reprodukcija ove vrste sezonska. Izvršen je i pregled lokaliteta na kojima su jedinke pronađene, kako bi se utvrdilo biraju li ih ženke kao mjesta za rađanje mladih.

Numerous karst dolines have been formed along the Croatian coast and many have been submerged during the Late Glacial and Holocene sea level rise. The coastal area of Cres Island in the Northern Adriatic is a typical example of this geomorphological setting, where transitional forms from subaerial to submerged dolines are present. Once dolines are formed they can accumulate soil, water and sediments due to their morphology. Sediments are an especially valuable source of environmental data. This paper presents the results of the study of foraminiferal assemblages and sediment geochemistry, supplemented with grain-size and mineralogical data, from the marine ponds developed in the karst dolines on Cres Island. Obtained data is correlated with the sediment core record from submerged dolines in the present-day embayments along the coastal zone of Cres Island. In total, 3 sediment cores were collected in the marine ponds Marinska, Arcij and Podbrajde, while 2 longer sediment cores have been extracted from the Jaz and Sonte embayments. The Marinska, Arcij and Podbrajde marine ponds have distinct geochemical and mineralogical sediment compositions, with monospecific foraminiferal assemblages and generally differ from each other. The common characteristics are their high N and P concentrations and the algal origin of organic matter. Agglutinated foraminiferal taxa (Haplophragmoides canariensis and Trochammina inflata), typical for intertidal environments, are abundant in the brackish-water Marinska pond, while stress-tolerant species Ammonia tepida has been identified in the Arcij marine pond. Environmental conditions in the Podbrajde marine pond did not facilitate the development of a rich foraminiferal fauna. Results from the present- day marine ponds enabled recognition of similar environments in the sediment cores collected in the Jaz and Sonte embayments that were progressively inundated during the Holocene sea level rise. A palaeo-marine pond existed in the Sonte embayment until 6610 cal BP, when the sea flooded the investigated area. A marine pond in the Jaz embayment was formed at 711 cal BP. Low-diversity foraminiferal assemblages in these palaeo-ponds are similar to those recognized in the present-day Arcij marine pond on Cres Island. However, differences in the geochemical composition of palaeo-marine ponds, in comparison to the present-day ponds, exist. They might be attributed to climate variability over time and variations in the geological setting of each environment. High Mo concentrations and abundant organic matter content are the main sediment characteristics of the recognized palaeo-marine ponds in the Jaz and Sonte embayments.

This study combines radiocarbon (14C) analysis and sclerochronology research, an approach that to the best of our knowledge, has not yet been applied using bivalves from the Mediterranean Sea. We analyzed shells from the North Adriatic Sea: live- and dead-collected specimens of the infaunal bivalveGlycymeris pilosaand two dead-collected specimens ofGlycymerissp. According to crossdating results, growth increment time series obtained from acetate peels of the dead-collectedG. pilosa(S3FP11) indicate the potential for creating longer chronologies from live and dead-collected specimens. The greatest longevity was seen in the dead-collectedGlycymerissp. specimen S3F3, estimated to be ~130 years (started growing AD 1678–1742 and died AD 1826–1860), indicating the potential to extendGlycymerisgrowth increment chronologies to past centuries. The highest ∆14C values obtained corresponded to the calendar year 1974. The14C record obtained fromG. pilosacorrelates well with the modeled surface ocean (mixed-layer) bomb pulse curve (Reimer et al. 2009). Based on the results obtained from the shell growth increment assigned to AD 1950, the reservoir age and reservoir correction (ΔR) are 264±23 years and –6±32 years, respectively.

Length–weight relationships of bivalve species collected during razor clam (Ensis minor) surveys along Italian coastal waters (Northern Adriatic and Tyrrhenian Sea) in the 3-year period 2016–2018 are reported. A total of 13,588 individuals, belonging to 12 bivalve species and 20 populations between the Adriatic and Tyrrhenian Seas, were sampled for this study. Analyzing growth parameters for each population, we found 11 allometries and nine isometries. About half of the species investigated showed different growth characteristics between the two areas.

© 2019 Mediterranean Marine Science. This paper presents an attempt to evaluate physiological response differences (cardiac activity) in the Mediterranean mussel Mytilus galloprovincialis and its use as a biomarker to assess water quality in Boka Kotorska Bay. Mussels were sampled in 2014 from three different sites in Boka Kotorska Bay, which faces various anthropogenic pressures. Both the heart rate recovery time (Trec) and the coefficient of variation in the heart rate (CVHR) were tested, in compliance with the standardized test procedure, using short-term reduction of water salinity as a stress factor to study the adaptive capacity of the tested mussels. The highest values of both Trec and CVHR in Port Bijela, Trec = 77.3 ± 7.2 min; CVHR = 10%, indicated that the water quality at this site was worse when compared to other locations (Stoliv and Dobrota). The values at Port Bijela were significantly higher compared to Stoliv and Dobrota. The lowest values of Trec were found in the mussels from Stoliv (47.3 ± 3.8 min), which implies better water quality compared to the other locations. Although, higher values of Trec were obtained for Dobrota (53.3 ± 4.8 min) compared to Stoliv, the differences were not statistically significant. The applied rapid method of environmental biomonitoring using cardiac activity in mussels could be a useful tool in water quality assessment. Thus, the relevant authorities could timely plan and carry out activities to maintain good ecological status of the marine coastal areas of Montenegro, in order to minimize the effect of emergency situations on both animal and human health in the region, as well as limiting wastewater discharge.

The main circulatory medium of echinoderms is the coelomic fluid. Biochemistry of coelomic fluid is very complex and slightly different from seawater. The main aim of this research was to analyse concentration of electrolytes (potassium, calcium, magnesium, chlorine and sodium), heavy metals (lead, chromium, cadmium and cobalt) and iron in coelomic fluid of sea urchin, Arbacia lixula as an indirect indicator of seawater contamination. After precise statistical evaluation it was observed that electrolyte concentrations were; Na 189.20±11.41 mmol/l, Cl 134.06±37.08 mmol/l, Mg 4.24±1.08 mmol/l, Ca 3.04±0.84 mmol/l. Biochemical content of heavy metals in coelomic fluid was; Co 1.292±0.879 ppm, Pb 0.644±0.131 ppm, Cr 0.116±0.055 ppm, Cd 0.031±0.017 ppm and iron 0.259±0.058 ppm, and it depends on the potential accumulation level in the organism. The composition of electrolyte and heavy metal content varies depending on the composition of seawater. Obtained values are within the range of values most commonly found in low polluted areas of the Adriatic sea. Similar models may be applied for monitoring of heavy metal contamination in marine environment.

Tritia mutabilis (Linnaeus, 1758) represents a marine gastropod species of ecological and economical importance especially in coastal areas of the central Adriatic Sea (Italy). T. mutabilis encloses its fertilized eggs within capsules which play a protective role in the embryo defense against adverse environmental factors. Egg capsules are attached to any hard substrates and the availability of adequate substrates for oviposition represents therefore a major determinant of reproductive output of this species. The aim of the present study was to provide the first comprehensive monitoring of T. mutabilis egg capsule deposition and intracapsular embryonic patterns using specific artificial substrates and innovative analytical approaches. Square-based pyramid structures were placed within an area subjected to small-scale fishing activity along the Italian coastal waters of the central Adriatic Sea and monitored from March to June 2019. In addition, a machine learning-based approach was developed in order to speed up and automate time-consuming counting procedures of egg capsules attached on each pyramid. Overall, egg capsules were deposited on the almost totality of the artificial substrates reaching values of the surface coverage per site ranging from 31 to 97%. These findings lead to a quantitative estimation of egg number per site included between 27,060 and 62,940 capsules. Our results demonstrate that using these artificial substrates together with monitoring of both egg capsule deposition patterns and intracapsular developmental stages may be useful to improve the T. mutabilis stock management.

This study examined total mercury (THg) and selenium (Se) levels in archive samples (white and red muscles, liver, gills) of the wild Atlantic bluefin tuna (ABFT) (Thunnus thynnus) (n = 18) captured in the central Adriatic Sea. The influence of fish size, age, and tissue type on element distribution was examined. There were significant differences in THg and Se levels, and Se:THg molar ratios among tissues. THg levels were highest in liver and lowest in gills (liver > red muscle > white muscle > gills), while Se levels were also highest in liver but lowest in white muscle (liver > red muscle > gills > white muscle). Se:THg molar ratios were highest in gills (22–82), intermediate in liver (11–29) and red muscle (7–36), and lowest in white muscle (1.7–7.6). Concentrations of THg in all tissues and Se in liver and caudal muscle were positively correlated with tuna age and size, while the Se:THg molar ratio in gills and all white muscles was negatively correlated with tuna age and size, indicating that the protective role of Se against THg is reduced in older specimens. The selenium health benefit values (HBVSe) were above zero in all tissues, indicating a small excess of Se after Hg sequestration. However, since the obtained HBVSe for edible tissues were near zero (0.01–0.04), and more than 70% of white muscle samples and all red muscle samples exceeded the EU regulatory limit for THg in fish muscle, it would be advisable to limit their intake in adults to one meal per month.

Three specimens of decapod shrimp Eualus drachi Noël, 1978, were found in the red coral rem-nant collected for commercial purposes near the island Sveti Andrija, Croatia. It is the first record of this species in the Adriatic Sea. The decapod biodiversity of deeper coralligenous habitats, such as the red coral colonies, is poorly investigated in contrast to coastal areas and soft bottoms of traditional trawling grounds. This paper highlights the usefulness of examining the remnants of a commercial coral extraction originating from previously less investigated marine habitats in order to improve the knowledge on the biodiversity of such habitats., Tri primjerka kozice Eualus drachi Noël, 1978, pronađena su u ostatku crvenog koralja prikupljenom u komercijalne svrhe u blizini otoka Sveti Andrija, Hrvatska. To je prvi nalaz ove vrste u Jadranskom moru. Biološka raznolikost deseteronožaca dubljih koraligenih staništa (poput kolonija crvenih koralja) slabo je istražena za razliku od obalnih područja i mekog dna tradicionalnih koćarskih područja. U ovom radu se naglašava korisnost ispitivanja ostataka komercijalne ekstrakcije koralja porijeklom iz prethodno manje istraženih morskih staništa kako bi se poboljšalo znanje o biološkoj raznolikosti takvih staništa.

Assessing the potential biomass yield is a key step in aquaculture site selection. This is challenging, especially for shellfish, as the growth rate depends on both trophic status and water temperature. Individual ecophysiological models can be used for mapping potential shellfish growth in coastal areas, using as input spatial time series of remotely sensed SST and chlorophylla. This approach was taken here to estimate the potential for developing oyster (Crassostrea gigas) farming in the western Adriatic Sea. Industry relevant indicators (i.e., shell length, total individual weight) and days required to reach marketable size were mapped using a dynamic energy budget model, finetuned on the basis of site-specific morphometric data collected monthly for a year. Spatially scaled-up results showed that the faster and more uniform growth in the northern Adriatic coastal area, compared with the southern one, where chlorophyll-a levels are lower and summer temperatures exceed the critical temperature limit for longer periods. These results could be used in planning the identification of allocated zones for aquaculture, (AZA), taking into account also the potential for farming or co-farming C. gigas. In perspective, the methodology could be used for getting insights on changes to the potential productivity indicators due to climatic changes.

The goal of most studies published on sand contaminants is to gather and discuss knowledge to avoid faecal contamination of water by run-offs and tide retractions. Other life forms in the sand, however, are seldom studied but always pointed out as relevant. The Mycosands initiative was created to generate data on fungi in beach sands and waters, of both coastal and freshwater inland bathing sites. A team of medical mycologists and water quality specialists explored the sand culturable mycobiota of 91 bathing sites, and water of 67 of these, spanning fromthe Atlantic to the EasternMediterranean coasts, including the Italian lakes and the Adriatic, Baltic, and Black Seas. Sydney (Australia) was also included in the study. Thirteen countries took part in the initiative. The present study considered several fungal parameters (all fungi, several species of the genus Aspergillus and Candida and the genera themselves, plus other yeasts, allergenic fungi, dematiaceous fungi and dermatophytes). The study considered four variables that the team expected would influence the results of the analytical parameters, such as coast or inland location, urban and non-urban sites, period of the year, geographical proximity and type of sediment. The genera most frequently found were Aspergillus spp., Candida spp., Fusarium spp. and Cryptococcus spp. both in sand and in water. A site-blind median was found to be 89 Colony-Forming Units (CFU) of fungi per gram of sand in coastal and inland freshwaters, with variability between 0 and 6400 CFU/g. For freshwater sites, that number was 201.7 CFU/g (0, 6400 CFU/g (p = 0.01)) and for coastal sites was 76.7 CFU/g (0,3497.5 CFU/g). For coastalwaters and allwaters, themedianwas 0 CFU/ml (0, 1592 CFU/ml) and for freshwaters 6.7 (0, 310.0) CFU/ml (p < 0.001). The results advocate that beaches should bemonitored for fungi for safer use and better management. Highlights: Fungi are missing from water and sand health protection regulatory parameters; Both sand and water should be monitored for fungi; The median value of 89 CFU/g of all fungi may serve as a reference for sand regulation; Candida albicans, dermatophytes, endemic fungi and other fungi should be considered; Fungal analysis of water needs more data before reference values can be established. Acknowledgements: A. Abdillah, M. C. Esposto, J. Kabtani, K. Sarioglou, P. E. Verweij and F. Vieira for their collaboration in this study; the European Confederation of Medical Mycology for a seeding grant; the International Society for Human and Animal Mycology for some financial support; financial support from CESAM (UID/AMB/50017-POCI-01-0145-FEDER-007638) and CITAB (UID/AGR/04033/2019), via FCT/MCTES, from national funds (PIDDAC), cofounded by FEDER, (PT2020 Partnership Agreement and Compete 2020) and an NHMRC APP1121936 to W. Meyer; National and Kapodistrian University of Athens, Greece, Special Accounts for Research Grants (SARG K.A. 70/3/6915). info:eu-repo/semantics/publishedVersion

Two new species of calanoid copepods are described; Metacalanus adriaticus sp. nov. from an anchialine cave on Vis Island, and Paramisophria tvrtkovici sp. nov. from Orljak Cave, located in the lower part of River Krka estuary, near the town of Šibenik (Croatia). This is the first report of arietellid copepods found in any anchialine cave along the coast of the Adriatic Sea. In M. adriaticus sp. nov. the antennules are asymmetrical in both sexes (the female left antennule is 18-segmented, right 20-segmented; male left 16-segmented and right 20-segmented); the uniramous fifth legs of the female are 2-segmented; the terminal segment of the fifth leg in both sexes is the longest; and in the male the fifth leg exopod is 2-segmented. In P. tvrtkovici sp. nov. the antennules of both sexes are asymmetrical with the left antennule longer than the right, the female antennule is 21-segmented on both sides; the male left antennule is 19-segmented, the right 21-segmented; the armature of the terminal exopod segment of leg 1 is II, 2 ,2; the male fifth legs have a rudimentary endopod on the left leg, the third exopodal segment is smallest and bears three unequal processes on its outer margin, and the terminal spine is completely separated from the segment. On the right leg the third segment carries two short, unequal processes on its outer distal margin, as well as a long sigmoidal spine which is fused to the segment. It is inferred that, after the last glaciation, these new Arietellids moved out from their southern Adriatic refuge, colonizing first the anchialine habitats of the outer eastern Adriatic islands and then spreading along the coast.

The study focused on the macroscopic, histological, and biometric analysis of European hake females in GSA 17 (Central-North Adriatic Sea). From 2013 to 2015, 976 females were collected and analyzed monthly. Though females in spawning conditions were found during the whole year, the trend of GSI showed a peak of the reproductive season from April to July in 2014 and 2015. HSI and Kn reached the highest values in September, after the spawning peaks. In 2013, the trend of these indices did not highlight an evident peak, probably due to an adverse event that occurred in the previous winter in the Adriatic shelf. The length at first maturity (L50) was estimated by macroscopic and histological approaches, resulting in 30.81 cm for the macroscopical length and 33.73 cm for the histological length, both values are higher than the current catching legal size. For the first time in this area, batch and relative fecundity were estimated. Relative fecundity was similar to the Mediterranean and the Atlantic stocks, whereas batch fecundity values were lower compared to other fishing grounds. Overall, the analysis of reproductive parameters plays a fundamental role in the sustainable management of this resource in an area as overfished as the Central-North Adriatic Sea.

In the last decades, human and industrial activities in the coastal areas have increased and that resulted in different types of contamination, including trace elements. Therefore, investigations of the southeastern Adriatic marine environment quality are intensified following seawater, biota, and sediment quality related to metals pollution. Since standard chemical analysis methods cannot provide accurate information about concentrations of trace elements in seawater, the seagrass Posidoniaoceanica (L.) Delile and the mussel Mytilusgalloprovincialis Lamarck, 1819, were used as water pollution bioindicators for identifying, especially, toxic trace elements in the Mediterranean. Surface sediment, seawater, seagrass (P. oceanica), and mussel (M. galloprovincialis) samples were collected in different seasons from the coastal area of Boka Kotorska Bay in the last 10 years (2006–2016), and analyzed in order to determine the seawater quality mainly related to Fe, Mn, Zn, Ni, Cu, Co, Cd, As, Pb, and Hg. Based on the analysis of the metal pollution index values (MPIs) in both species the highest metal concentrations were measured in winters for most of the studied trace elements. The Hg accumulation in both investigated organisms was the lowest and almost the same.

Blooms of invasive ctenophore Mnemiopsis leidyi can have massive consequences on fish stocks and marine food webs. The distribution, abundance and diet of this ctenophore were investigated in the northeastern (NE) Adriatic between 2016 and 2019. The abundance of M. leidyi was determined daily along the coast of Rovinj (Croatia), and its spatial distribution monitored by visual census from research vessels and by pelagic trawl during acoustic surveys in September of each year. Mesozooplankton samples were collected along the western coast of Istria by vertical tows from the bottom to the surface. Spatial distribution and abundance of anchovy ( Engraulis encrasicolus ) assemblages were determined by geo-referenced hydro-acoustic sampling using a scientific echosounder. Large swarms of M. leidyi covering several km 2 were regularly reported between July and November extending up to 25 NM from the western coast of the Istrian peninsula and reaching maximum offshore densities of 270 individuals per m 2 . The abundance of anchovy in the areas where M. leidyi was present evidently decreased. The content of M. leidyi ’s digestive tract and plankton samples consisted both mainly of cladocerans, copepods, pteropods, echinodermata and bivalvia larvae. Results indicate that M. leidyi may accumulate and increase its abundance in the stagnant and trophically rich areas of the northern Adriatic gyres, spreading to the surrounding larger areas with currents. We assume that M. leidyi presence correlates with a decrease in anchovy population due to competition for food (zooplankton). Our findings support the importance of implementing an international monitoring program throughout the Adriatic Sea and demonstrate the ability of current MEDIAS surveys to detect changes in the pelagic ecosystem throughout surveyed areas.

The aim of the present study isto characterise the diatom Pseudo-nitzschia community during a bloom period together with environmental conditions. High proliferation of Pseudo-nitzschia spp. was observed in September 2017 at the shellfish breeding area in the Krka River estuary (Central eastern Adriatic Sea). The peak of abundance (1.8 x 10 6 cells L -1 ) was recorded at 7 m depth, and the increased abundance persisted for four weeks.Morphological analyses of field samples based on scanning electron microscopy (SEM) revealed that Pseudo-nitzschia cf. arenysensis was prevailing (94%) in the Pseudo-nitzschia assemblage. Several strains were successfully isolated from net samples in order to better define morphological features and phylogenetic characterisation. The isolated Pseudo-nitzschia strains corresponded morphologically to the P. cf. arenysensis from the field samples, based on our SEM observations. Phylogenetic analysis demonstrated that the Croatian strains grouped with P. arenysensis using the ITS and LSU rDNA sequences. Spearman rank correlation showed that salinity was an important environmental factor affecting the vertical distribution of Pseudo-nitzschia spp. in this highly variable area. Availability of increased concentration of orthophosphates and ammonium and low Si: TIN ratio may have promoted the bloom of P. cf. arenysensis in the estuary.

The aim of the study was to explore the relationship between membrane-regulating functional lipids of three fucacean species and their associated epiphytic bacterial communities. The analyzed algae Treptacantha barbata, Carpodesmia crinita and Cystoseira compressa, formerly classified under the Cystoseira genus, are indigenous to the Adriatic Sea. The thalli of sampled Fucales species were divided into perennial and annual parts. T. barbata and C. crinita show high contents of mono- and polyunsaturated fatty acids but, however, show a clear distinction between branches, cauloids and apical parts. Along with the highest unsaturation degree (4.32), the C. crinita branches and apical parts demonstrated high proportion of both C18 and C20 polyunsaturated fatty acids, with eicosapentaenoic (C20:5 n-3) and arachidonic (C20:4 n-6) fatty acids up to 5.46% and 13.82%, respectively. The highest proportion of saturated fatty acids was found in thalli of C. compressa, particularly on cauloids and old branches (&ge, 90%). The similarity profile routine analysis of fatty acids and microbial community structure has shown clear separation of the cauloids and apical parts from the branches of C. crinita and T. barbata. Based on the nonmetric multidimensional scaling analysis several representatives of the Gammaproteobacteria class, identified as Vibrionales (Vibrio), Cellvibrionales and Xanthomonadales, which contributed strongly to the separation of T. barbata apical parts and branches, C. compressa receptacles and C. crinita branches from the T. barbata cauloids and C. crinita apical parts and cauloids. The highest richness in polyunsaturated fatty acids, in particular C18:3(n-3), C20:4(n-6) and C20:5(n-3), was observed on branches, accompanied by a distinctive epiphytic microbial structure dominated by numerous representatives with potentially beneficial biological activity. The results showed a strong relationship between fatty acid profiles of the analyzed species and phycosphere community structure, underlining the host physiological condition in shaping the biological interactions and maintaining a healthy microbiome, as well as compiling the ecophysiological and molecular research in order to better assess the resilience of the ecosystem.

Este artículo contiene 11 páginas, 5 figuras, 6 tablas., In the Mediterranean Sea, the symbiosis between the gorgonian Paramuricea clavata (Risso, 1826) and the polychaete Haplosyllis chamaeleon Laubier, 1960 (Annelida, Syllidae, Syllinae) has only been documented from the western basin. Our findings extend its geographic distribution to the north-central basin and represent the first record of H. chamaeleon in Italy and Croatia. Periodic observations from the Ligurian Sea allowed establishing that the symbiont occurs on P. clavata almost throughout the year, showing a reproductive period longer than previously reported. Morphometric comparisons of three Mediterranean populations, from Portofino Promontory (Ligurian Sea), Cape of Creus (Catalan Sea) and Chafarinas Archipelago (Alboran Sea) proved that there were no significant differences in body measurements, whilst the observed differences in dorsal cirri length pattern could be consider intra-specific. Our behavioural observations confirmthat the species had (i) a kleptoparasitic behaviour, (ii) did not cause injuries to the host and (iii) did not induce the host to generate any malformation., Open access funding provided by Università Politecnica delle Marche within the CRUI-CARE Agreement. This research has been performed within the frame of the European Union’s Horizon 2020 research and innovation programme, as part of the project MERCES: Marine Ecosystem Restoration in Changing European Seas (grant agreement No. 689518) and is a contribution of Daniel Martin to the Consolidated Research Group on Marine Benthic Ecology of the Generalitat de Catalunya (2017SGR378) and to the Research Project PopCOmics (CTM2017-88080), funded by the ‘Ministerio de Ciencia, Innovación y Universidades’ of Spain (MICINU), the ‘Agencia Española de Investigación’ (AEI) and the European Funds for Regional Development (FEDER).

Population dynamics in lower metazoans are strongly regulated by environmental factors. The running climate crisis could affect regularity of life strategies; therefore, studying life cycles and reproductive patterns of benthic species may provide key information on effects of environmental changes in temperate seas. The North Adriatic Sea is a peculiar basin due to high food availability and high fluctuations of physical parameters. Here, cnidarians are one of the most abundant taxa and sea anemones are the largest representatives. Aim of this study is to assess the life history and the reproductive biology of two potential species models: the sea anemones: Anemonia viridis and Exaiptasia diaphana. The present research is the first quantitative study on the variations in abundance and reproductive biology of the two species. We reported new insights about abundance fluctuations throughout the year and about the gametogenesis of the two sea anemones. In particular, data on spermatogenesis of A. viridis from the Mediterranean Sea were supplied for the first time.

Since the 1960 s, there has been a rapid expansion of drilling activities in the central and northern Adriatic Sea to meet the increasing global energy demand. The discharges of organic and inorganic pollutants, as well as the alteration of the sediment substrate, are among the main impacts associated with these activities. In the present study, we evaluate the response of benthic foraminifera to the activities of three gas platforms in the northwestern Adriatic Sea, with a special focus on the Armida A platform for which extensive geochemical data (organic matter, trace elements, polycyclic aromatic hydrocarbons, other hydrocarbons, and volatile organic compounds) are available. The response to disturbance is assessed by analyzing the foraminiferal diversity using the traditional morphology-based approach and by 18S rDNA-based metabarcoding. The two methods give congruent results, showing relatively lower foraminiferal diversity and higher dominance values at stations closer to the platforms (

This study reports the shapes, dimensional classes, types and counts of microplastics (MPs) found in 23 individuals of N. norvegicus collected from two wild populations of the Adriatic Sea (Mediterranean basin). The focus was on three different anatomical compartments (gut, hepatopancreas and tail), which were analysed separately. MPs were found in all the investigated individuals with an average of about 17 MPs/individual. Fragments were predominant over fibers with a ratio of about 3:1. The majority of MPs were in the dimensional range 50–100 μm. The predominant polymers were polyester, polyamide 6, polyvinyl chloride and polyethylene, which together constitute about 61% of all the MPs found. Fragments were more concentrated in the hepatopancreas, with no significant difference between gut and tail, while fibers were more concentrated in the gut than in the tail with hepatopancreas somehow in between. The dimensional class of the MPs influences their anatomical distribution. There were no statistical differences among individuals from the two sampling sites. Sex of the individual did not influence the level of retained MPs, while length had a very marginal effect. The information reported here contributes to understanding of the possible risks linked to human consumption of different tissues from contaminated Norway lobsters.

1. The Mediterranean common dolphin (Delphinus delphis), considered to have been very common in the past, had undergone a dramatic decline across most of the basin by the end of 1970s. In the northern Adriatic Sea, one of the regions with most available historical information, the common dolphin is thought to have been the most common and abundant cetacean throughout most of the 20th century. However, by the end of 1970s, it had virtually disappeared from the region and is now considered generally absent from the entire Adriatic Sea. 2. This contribution summarizes the occurrence of common dolphins in the Gulf of Trieste and provides a brief review of published records in other parts of the Adriatic Sea. 3. Systematic boat surveys in the wider area of the Gulf of Trieste between 2002 and 2019 confirmed that the common bottlenose dolphin (Tursiops truncatus) is the only regularly occurring cetacean species in this area. Despite this, several records of common dolphins were documented in the Gulf of Trieste between 2009 and 2012, through sightings of live animals or recovery of dead stranded animals. 4. Dorsal fin markings allowed the photo‐identification of some of these, suggesting that at least four different live individuals (three adults and one calf) occurred here in recent times. Most cases involved single adult individuals, but one included a mother‐calf pair that was temporarily resident in a port for several months, a behaviour atypical for this species. Photo‐identification showed that the presumed mother had previously been sighted in the Ionian Sea in Greece, over 1,000 km from the Gulf of Trieste, making this the longest documented movement for this species worldwide. 5. At present, the common dolphin continues to be rare in the region. Publisher PDF

The Krka River estuary is a karstic, permanently stratified estuary due to the strong freshwater inflow. It is a special environment in which to study the phytoplankton community, especially because this area is an important aquaculture site. Among other potentially toxic phytoplankton species, the diatom genus Pseudo-nitzschia occurs frequently and is a potential source of domoic acid (DA), causing shellfish toxicity and human intoxication. The main objective was to examine the dynamics of the phytoplankton community and, in particular, the genus Pseudo-nitzschia in the upper part of the Krka estuary, through monthly sampling over two years. The phytoplankton community was analysed using light microscopy and scanning electron microscopy to determine the diversity of Pseudo-nitzschia species and characterise the environmental parameters associated with a high abundance of Pseudo-nitzschia species. Seven Pseudo-nitzschia species were identified in the investigation, with higher frequencies and abundances in the less variable layer, at a 7 m depth. Blooms of Pseudo-nitzschia were noted in the late summer/early autumn, dominated by P. delicatissima/arenysensis. Winter assemblages were characterised by P. pseudodelicatissima/cuspidata, P. calliantha, and P. subfraudulenta, and were associated with domoic acid occurrence in shellfish.

In order to expand the fragmentary knowledge on the interactions between the environment and copepod distribution in the deep offshore Adriatic Sea, microcopepod assemblages were investigated during 31 cruises in the 1200-m deep central part of the South Adriatic Pit (SAP), from May 1998 to December 2009. Samples were collected in 8 depth layers, using a 53-μm mesh Nansen net equipped with a closing system. The taxonomic composition and vertical and temporal distributions of copepod abundances were analyzed, considering naupliar stages for all species combined, total calanoid copepodites, copepodite stages and adults separately for oithonids and oncaeids, and all post-naupliar stages combined of harpacticoids and mormonilloids. Corycaeid copepods are not considered in the present study. Data are presented for 41 non-calanoid copepod species, as well as for 7 undetermined morphospecies. Within the family Oncaeidae, four species new to the Adriatic Sea fauna are registered. Nauplii were generally the numerically dominant group, especially in the upper epipelagic layers, where they outnumbered all total post-naupliar stages by a factor of an average 3.5. Oncaeids were notably abundant, accounting in total post-naupliar copepods for an average proportion of 33% in the upper 50 m and 74% between 300- and 400-m depth. In the epipelagic zone, copepod abundances were enhanced by the cyclonic circulation which enriches the central part of the SAP with new primary production. A strong advection of Levantine Intermediate Water (LIW) influenced the post-naupliar abundances also in mesopelagic and deeper layers, by promoting the sinking of heavy water mass from the connected middle Adriatic sub-basin which enhances the trophic conditions and transports new organisms into the deeper layers of the SAP. Therefore, the variability in copepod abundances was influenced not only by the seasonal temperature fluctuations but also by the productivity conditions in the SAP which are connected to the movements of regional water masses and the resulting effects on the internal Adriatic circulation.

Three new species of the neogastropod family Raphitomidae Bellardi, 1875, are described from the Croatian waters of the Adriatic Sea: Raphitoma petanii Prkic, Giannuzzi-Savelli & Pusateri n. sp., R. pusaterii Prkic & Giannuzzi-Savelli n. sp. and R. stanici Prkic, Giannuzzi-Savelli & Pusateri n. sp. The new species are diagnosed by teleoconch characters and by genetic data (COI sequences) in an integrative taxonomy framework. They belong to a group of species with microgranules on the external surface of all teleoconch whorls and all three have a multispiral protoconch indicating a planktotrophic larval phase. The first two species are so far known only from material found in Croatia. R. petanii Prkic, Giannuzzi-Savelli & Pusateri n. sp. and R. stanici Prkic, Giannuzzi-Savelli & Pusateri n. sp. are predominantly shallow-water species, whereas R. pusaterii Prkic & Giannuzzi-Savelli n. sp. has been so far collected only from deeper bottoms with presence of the red coral, Corallium rubrum (Linnaeus, 1758). Syntypes of Murex echinatusBrocchi, 1814 are figured and commented.

Pseudo-nitzschia H. Peragallo (1900) is a globally distributed genus of pennate diatoms that are important components of phytoplankton communities worldwide. Some members of the genus produce the neurotoxin domoic acid, so regular monitoring is in place. However, the identification of toxic members in routine samplings remains problematic. In this study, the diversity and seasonal occurrence of Pseudo-nitzschia species were investigated in the Gulf of Trieste, a shallow gulf in the northern Adriatic Sea. We used time series data from 2005 to 2018 to describe the seasonal and inter-annual occurrence of the genus in the area and its contribution to the phytoplankton community. On average, the genus accounted for about 15 % of total diatom abundance and peaked in spring and autumn, with occasional outbreaks during summer and large inter-annual fluctuations. Increased water temperature and decreased salinity positively affected the presence of some members of the genus, while strong effects could be masked by an unsuitable definition of the species complexes used for monitoring purposes. Therefore, combining morphological (TEM) and molecular analyses by sequencing the ITS, 28S and rbcL markers, eight species were identified from 83 isolated monoclonal strains: P. calliantha, P. fraudulenta, P. delicatissima, P. galaxiae, P. mannii, P. multistriata, P. pungens and P. subfraudulenta. A genetic comparison between the isolated strains and other strains in the Mediterranean was carried out and rbcL was inspected as a potential barcode marker in respect to our results. This is the first study in the Gulf of Trieste on Pseudo-nitzschia time series from a long-term ecological research (LTER) site coupled with molecular data. We show that meaningful ecological conclusions can be drawn by applying integrative methodology, as opposed to the approach that only considers species complexes. The results of this work will provide guidance for further monitoring efforts as well as research activities, including population genetics and genomics, associated with seasonal distribution and toxicity profiles.

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗ, This study reports, for the first time, different physico-chemical analyses, of Mediterranean mussels (Mytilus galloprovincialis) from harvesting areas in the Montenegro coast of the Adriatic Sea, in order to evaluate the influence of origin on different parameters and assessed the quality of shellfish grown in this area. The Boka Kotorska Bay is situated in Montenegro, in the south-eastern part of the Adriatic Sea The mussel samples were collected at the same time in the spring of 2019 at six locations in Boka Kotorska Bay, Montenegro: Kotor and Tivat Bays. Biometric parameters, percentage of meat, condition index, proximate composition, sensory evaluation and lipid profiles of mussels were studied. The concentrations of some micro and macro elements and heavy metals in mussels, were also analyzed. Significant differences were found between mussels from different locations. Mean biometric parameters of mussels grown in Sv.Nedjelja, were considerably higher than in mussels grown elsewhere.. Protein, lipid, ash and glycogen content were varied from 7.80 to 10.26%; 1.36 to 2.18%; 1.73 to 3.34% and 12.81 to 15.38%, respectively. Gas chromatographic analysis showed that polyunsaturated fatty acids (PUFAs) were dominant lipids in mussels (37.56 to 41.08%), followed by monounsaturated (MUFAs) (30.52 to 38.31%) and saturated (SFAs) (21.89 to 29.45%) fatty acids. Fatty acid profiles were investigated and revealed high contents of n-3 PUFAs and high n-3/n-6 ratios in all mussels from Montenegro In the mussel samples high concentrations of K, Mg, Ca, and Na, and much lower concentrations of Fe, Mn, Zn, and Cu were found. Some of toxic elements (As, Pb, Hg and Cd) were determined also.. The qualitative sensory assessment showed that all mussels were acceptable. All mussels in the current study achieved scores of 3 or more out of 5 in the qualitative category. Data on biochemical composition and quality indices of the mussels cultured in the Boka Kotorska Bay demonstrated that these products could be accepted well by consumers and could compete with other currently available mussels from other locations in Adriatic Sea.

On 3rd June 2018 three juvenile specimens of Polyprion americanus were captured in the Gulf of Trieste. The wreckfish is a long-lived deep-water demersal species characterized by an extended pelagic juvenile phase. The juvenile forms are recurrently recorded in the northern Adriatic and due to data deficiency for this species, original morphometric data are shown. The occurrence of P. americanus in the Gulf of Trieste is not a typical case of thermophilic species moving northward due to Mediterranean tropicalization, rather its recurrent appearance could be investigated for specific hydrological conditions coupled to its peculiar life span., Dana 3. lipnja 2018. u Tršćanskom zaljevu ulovljena su tri jedinke mlađi kirnje glavulje Polyprion americanus. Kirnja glavulja je dugovječna vrsta duboke vode, koju karakterizira produljena pelagična faza mlađi. Jedinke mlađi opetovano se bilježe u sjevernom Jadranu, a zbog nedostatka podataka za ovu vrstu, prikazani su izvorni morfometrijski podaci. Pojava P. americanus u Tršćanskom zaljevu nije tipičan slučaj termofilnih vrsta koje se kreću prema sjeveru zbog mediteranske tropikalizacije, već bi se njihov ponovljeni nalaz mogao istražiti u specifičnim hidrološkim uvjetima zajedno s osebujnim životnim vijekom ove vrste.

During a survey of the diatom flora attached to carapaces of loggerhead sea turtles (Caretta caretta) from the Adriatic Sea, a large population of an unknown marine achnanthoid species was observed that could not be assigned to any of the currently described monoraphid diatom genera. Detailed morphological analysis based on scanning electron microscopy observations and comparison with a large number of monoraphid genera such as Madinithidium, Scalariella, Kolbesia and Karayevia, resulted in the description of the new benthic marine genus Majewskaea gen. nov. with the newly described Majewskaea istriaca sp. nov. as generitype. The new genus is characterized by a sternum valve showing a clear recurving ridge surrounding the entire valve margin, the presence of macroareolae closed internally by perforated hymenes, separated by a longitudinal hyaline area, a well-developed sternum and vestigial raphe slits. The raphe valve has a simple straight raphe with bent terminal fissures, a very fine striation pattern composed of macroareolae cut in two by a longitudinal hyaline zone, and a very shallow mantle. The new genus is illustrated using both LM and SEM observations and compared with other resembling marine and brackish Planothidium monoraphid species.

The Bari Canyon System (BCS) is located on the southwestern Adriatic margin, in the Central Mediterranean Sea indenting the continental shelf at approximately 200 m. It is characterized by a rough morphology, with two main parallel branches and a channel–levee complex with subvertical flanks, and a variable substrate with rocky outcrops along the canyon flanks. The geological context and the presence of two different dense water masses, the Levantine Intermediate Water (flowing along slope) and the North Adriatic Dense Water (cascading down slope), impacting the canyon act as major drivers for the settlement of valuable biota, such as cold-water corals (CWC), among which Madrepora oculata is the main frame builder. Due to the relevance of its CWC habitat, the BCS has been explored since 2003 by several oceanographic cruises and a huge amount of multidisciplinary data (e.g., geophysical data, sediment samples, ROV images, CTD and mooring deployments) was collected to map the BCS habitat at different scales with different methodologies. The abiotic and biotic components of the BCS benthic habitats were manually mapped and classified, applying a hierarchical scheme (CoCoNet classification scheme) to categorize and integrate at different scales every habitat component to obtain a comprehensive view of the benthoscape. The CWC habitat mapping was also supported by habitat suitability models implemented for the BCS (Ecological Niche Factor Analysis, Maximum Entropy—Maxent; Generalized Linear Models), to infer the habitat extent within the canyon.

The common bottlenose dolphin (Tursiops truncatus) population along the eastern Adriatic coast is believed to comprise discrete communities, yet many of them are unstudied. This study provides the first description of occurrence and demographic parameters for the community inhabiting waters of North Dalmatia. Dedicated boat-based surveys conducted in summer months from 2013 to 2017 resulted in 13, 896 km of research effort and 284 dolphin sightings from which 336 individuals were identified. Site-fidelity analysis revealed that 52.1% of encountered marked adults occur in the area regularly or occasionally. No significant difference among years could be found for mean group sizes (5.73–7.46) and group encounter rates (1.159–1.942 groups/100 km). Pollock's Robust Design models estimated annually variable adult apparent survival (0.737–0.986) and constant temporary emigration rate of 0.172. The estimated abundance varied annually from 116 to 138 individuals and showed a negative slope, but a significant trend could not be confirmed. Age-dependent models estimated first-year calf survival at 0.875. These results provide a baseline for informed management of two Sites of Community Importance, and a benchmark for future monitoring in North Dalmatian waters, an area under significant anthropogenic pressure.

The Tricase Canyon is a 20-km-long submarine canyon, incising the southernmost Apulian margin at the boundary between the Adriatic and Ionian Seas, in the Mediterranean basin. The canyon indents the continental margin at depth of –120 m and reaches a maximum depth of approximately –900 m. The Tricase Canyon is disconnected from direct fluvial system and has no other tributaries. The shallower area of the canyon is generally characterized by a sparse cnidarian occurrence which includes Protoptilum carpenteri, representing the easternmost occurrence of this species known in the Mediterranean basin. The cold-water corals Madrepora oculata, Desmophyllum pertusum, and Desmophyllum dianthus colonize deeper areas (approximately –800 m), settling preferentially on blocks interpreted as mass waste deposits.

The capture-based aquaculture of the Atlantic bluefin tuna (Thunnus thynnus) starts with the catch of wild individuals, a slow-operating transport to the rearing facilities, introduction to rearing cages, and adaptation to the captive environment; all bearing significant risks for the onset of stressful conditions that consequently can result in unexpected mortalities.In order to explore whether the survival success through the farming cycle might be monitored at the genetic level and linked to several immunity and stress response associated genes, we have developed a new set of 13 EST-SSRs for T. thynnus and subsequently analysed 334 samples of juvenile wild-caught tuna and captive-reared adults during two consecutive farming cycles in the Adriatic Sea.The results evidenced a low FST value (0.005) with similar allele frequencies and no major allele loss between investigated groups. Two tested approaches for the identification of loci under selection did not indicate departure from neutrality for any of the 13 EST-SSRs, suggesting that the latter could not be considered adaptive in the studied context.Our results are in agreement with other studies that attempted to detect adaptive signals in T. thynnus, stressing the problem associated with the sampling design of a species with complex migratory behavior, reproduction and particular zootechnical practices employed at the farms. Nonetheless, characteristics of 13 new polymorphic loci reported here contribute to the broadening of the existing EST-SSRs resource, being a useful asset in future genetic studies of T. thynnus.

Additional records of the Norwegian skate Dipturus nidarosiensis (Storm, 1881)from the Adri-atic Sea are reported. Two specimens were collected in the southern Adriatic Pit in 2008 and 2010, respectively. The records reported herein improve our knowledge on the distribution of a rarely encountered, deep water species D. nidarosiensis, whose presence has only recently been confirmed in the Mediterranean Sea.

The Mediterranean monk seal (Monachus monachus) is one of the most endangered marine mammals in the world. This species has been threatened since ancient times by human activities and currently amounts to approximately 700 individuals distributed in the Eastern Mediterranean Sea (Aegean and Ionian Sea) and Eastern Atlantic Ocean (Cabo Blanco and Madeira). In other areas, where the species is considered “probably extinct”, an increase in sporadic sightings has been recorded during recent years. Sightings and accidental catches of Mediterranean monk seals have become more frequent in the Adriatic Sea, mainly in Croatia but also along the coasts of Montenegro, Albania and Southern Italy. A Mediterranean monk seal pup was recovered on 27 January 2020 on the beach of Torre San Gennaro in Torchiarolo (Brindisi, Apulia, Italy). DNA was extracted from a tissue sample and the hypervariable region I (HVR1) of the mitochondrial DNA control region was amplified and sequenced. The alignment performed with seven previous published haplotypes showed that the individual belongs to the haplotype MM03, common in monk seals inhabiting the Greek islands of the Ionian Sea. This result indicates the Ionian Islands as the most probable geographical origin of the pup, highlighting the need to intensify research and conservation activities on this species even in areas where it seemed to be extinct.

Bivalve shells are among the most promising archives for high-resolution seawater temperature reconstructions. However, despite major research advances in bivalve sclerochronology over the past decades, estimating water temperature from shells remains a challenging task. This is largely because the most frequently used and widely accepted temperature proxy in bivalves, i.e., the shell oxygen isotope (δ18Oshell) value, also requires knowledge of changes in δ18O of the water (δ18Owater) in which the bivalve lived, which is rarely available for ancient environments. According to a few recent studies, the size and shape of individual biomineral units (BMUs) of the shell ultrastructure may serve as an independent temperature proxy that is also less vulnerable to diagenetic changes than isotope chemical proxies. However, the crossed-lamellar ultrastructure, which occurs in ca. 90% of all mollusk species, has hitherto not been investigated. Here, we evaluate the potential use of morphological properties of the BMUs in Glycymeris bimaculata as a proxy for water temperature. For this purpose we introduce a suitable preparation technique (immersion for 2 m in 0.001 vol% formic acid followed by 20–30 m in 3.5 vol% H2O2) and an automated image processing technique that tremendously speed up ultrastructure analysis (5 s versus one to 2 h image processing time with automated and manual methods, respectively) and increase the robustness of BMU measurements. Glycymeris is a particularly useful target taxon, because it is a cosmopolitan genus with evolutionary roots in the Upper Cretaceous, and some species of Glycymeris can attain a lifespan of more than two hundred years, which allows for long-term, high-resolution paleoclimate reconstructions. As in other previously studied ultrastructures, larger and more elongated BMUs formed in warmer water permitting temperature estimates with an error of 2.3 °C (1 σ). Since the new temperature proxy is unaffected by other environmental variables, including salinity, it can potentially be applied to (modern and fossil) specimens from brackish environments.

Population structure, growth, age, mortality and exploitation status of Atherina boyeri, caught in the period from June 2013 to May 2014 in the Lesina lagoon (Apulia region, southern Adriatic) was studied. Samples were taken each month by using beach seines . The length–weight relationship of all sand smell specimens was described by the equation W=0.012*TL 3.10; (R2= 0.84). Population parameters including the asymptotic length (L∞) and growth coefficient (K) were assessed to evaluate the stock status. The recruitment pattern was modeled with a FiSAT routine. The asymptotic length (L∞) was 111.0 mm, while the growth coefficient (K) was 0.68 year−1. The growth performance index ((φ’) reached 3.92. The total mortality coefficient “Z”, the natural mortality coefficient “M” and the fishing mortality coefficient “F” were estimated as 2.24, 1.48 and 0.76 year-1, respectively. Exploitation rate for the population of A. boyeri in the Lesina lagoon estimated as 0.34 was resulted still lower than the predicted maximum value of Emax 0.59. The probability of capture indicated that L50 was of 55.57 mm, indicating that the stock of sand smelt in Lesina lagoon is not being over-fished., Istraživana je struktura populacije, rast, starost, smrtnost i status eksploatacije olige Atherinaboyeri, ulovljene u razdoblju od lipnja 2013. do svibnja 2014. u laguni Lesina (regija Apulija, južni Jadran). Uzorci su uzimani svaki mjesec pomoću mreže potegače.Dužinsko-maseni odnos opisan je jednadžbom W = 0,012 * TL 3,10; (R2 = 0,84). Utvrđeni su parametri populacije, uključujući asimptotsku duljinu (L∞) i koeficijent rasta (K), kako bi se procijenilo stanje zaliha. Obrazac novačenja modeliran je FiSAT rutinom. Asimptotska duljina (L∞) iznosila je 111,0 mm, dok je koeficijent rasta (K) iznosio 0,68 godina − 1. Indeks učinka rasta (φ’) dosegnuo je 3,92. Ukupni koeficijent smrtnosti „Z“, koeficijent prirodne smrtnosti „M“ i koeficijent mortaliteta ribolova „F“ procijenjeni su na 2,24, 1,48 i 0,76 godina-1.Stopa eksploatacije populacije olige u Lesinskoj laguni procijenjena na 0,34 rezultirala je i dalje nižom od predviđene maksimalne vrijednosti Emax 0,59.

A live specimen of American lobster, Homarus americanus, was caught off Croatia, north Adriatic Sea. This is the first record of this species wild-caught in the Mediterranean. The origin of the caught specimen is unknown, yet possible pathways and potential impacts are discussed in the paper.

In this study, life-history traits (maximum and average size, size at maturity and fecundity) of two congeneric smooth-hounds, Mustelus mustelus and Mustelus punctulatus, which share a geographical distribution and experience a similar fishing exploitation, were estimated and compared between species. The results indicated a lower maximum and average size, a lower size at maturity and a higher fecundity in M. punctulatus compared with those in M. mustelus. Considering that these two species co-occur in the same areas and are caught by the same fishing gears, the results indicate a higher vulnerability to exploitation of M. mustelus compared with that of M. punctulatus.

Seasonal sampling of the seawater column and sediment in Adriatic coastal areas affected by various anthropogenic activities, primarily aquaculture, was conducted during 2017. In total, 32 samples from two sites (central and southern Adriatic) were analysed by 16S rRNA amplicon sequencing. This approach was selected to test the possibilities of using metabarcoding in studying marine cyanobacteria, exploring their ecology and potential as an indicator group in anthropologically stressed coastal environments. Additionally, physicochemical water column parameters, sediment granulometry and composition were assessed. Water column revealed a seasonal variation of amplicon sequencing variants (ASVs) closely related to Cyanobium PCC-6307, Prochlorococcus MIT9313 and Synechococcus CC9902, as well as seasonal grouping of physico-chemical parameters in PCA analysis. Sediment analysis uncovered greater community richness of 13 cyanobacterial genera and two uncultured groups. The most abundant in sandy gravels and gravelly sand type of sediments were ASVs closely related to Pleurocapsa PCC-7319 and Xenococcus PCC-7305. Furthermore, identified cyanobacterial ASVs predominantly displayed similarity to isolates from tropical areas (e.g. Neolyngbya, Chroococcidiopsis, Trichodesmium, etc.), which could indicate the tropicalization process already ongoing in the fish fauna of the Adriatic Sea.

This research aimed to study the abundance and molecular diversity of Vibrio parahaemolyticus-specific Halobacteriovorax strains isolated from seawater of the Adriatic Sea and the relationship between predator and prey abundances. Moreover, predator efficiency of the Halobacteriovorax isolates toward V. parahaemolyticus and Vibrio cholerae non-O1/O139 strains was tested. V. parahaemolyticus NCTC 10885 was used as primary host for the isolation of Halobacteriovorax from seawater by the plaque assay. Molecular identification was performed by PCR detection of a fragment of the 16S rRNA gene of the Halobacteriovoraceae family members. Moreover, 700 bp PCR products were sequenced and compared between them and to clones described for other sampling sites. Vibrio counts were performed on TCBS agar from 100 ml of filtered water samples and presumptive colonies were confirmed by standard methods. Predatory efficiency of Halobacteriovorax isolates was tested by monitoring abilities of 3-day enrichments to form clear lytic halos on a lawn of Vibrio preys, by the plaque assay. Out of 12 seawater samples monthly collected from June 2017 to May 2018, 10 were positive for V. parahaemolyticus specific Halobacteriovorax with counts ranging from 4 to 1.4 × 103 PFU per 7.5 ml. No significant relationship was found between Halobacteriovorax and Vibrio abundances. The 16SrRNA sequences of our Halobacteriovorax strains, one for each positive sample, were divided into three lineages. Within the lineages, some sequences had 100% similarity. Sequence similarity between lineages was always

European hake (Merluccius merluccius) is one of the most economically important fish for the Mediterranean Sea. It is an important predator of deep upper shelf slope communities currently characterized by growth overexploitation: the understanding of hake's diet might support next generation management tools. However, all current European hake diet studies depend on the morphological identification of prey remains in stomach content, with consequent limitations. In this study, we set up a metabarcoding approach based on cytochrome oxidase I PCR amplification and Miseq Illumina paired-end sequencing of M.merluccius stomach content remains and compared the results to classic morphological analyses. A total of 95 stomach contents of M.merluccius sampled in the North-Central Adriatic Sea were analyzed with both the metabarcoding and morphological approaches. Metabarcoding clearly outperformed the morphological method in the taxonomic identification of prey describing more complex trophic relationships even when considering the morphological identification of 200 stomach contents. Statistical analysis of diet composition revealed a weak differentiation among the hake's size classes, confirming an opportunistic feeding behavior. All the analyses performed showed the presence of a core of shared prey among the size classes and a cloud of size-specific prey. Our study highlights the exceptional potential of metabarcoding as an approach to provide unprecedented taxonomic resolution in the diet of M.merluccius and potentially of other marine predators, due to the broad-spectrum of detection of the primers used. A thorough description of these complex trophic relationships is fundamental for the implementation of an ecosystem approach to fisheries.

Investigation of parasites and diseases affecting molluscs of ecological and economic interest is critical for the management of native stocks and aquaculture. In recent years, much attention has been devoted to investigating the World Organisation for Animal Health listed infectious diseases, so that communities can be prepared to attend public health emergencies and avoid severe income losses. In this context, the health status of Mytilus galloprovincialis Lamarck, 1819 was analysed in two aquaculture sites (Strunjan Bay and Piran Bay, Slovenia), and in four natural mussel beds (Adriatic Croatia International Marinas Pula and Rovinj and St Catherine, Croatia; Marina Koper, Slovenia) along the coast of the northern Adriatic Sea. The mussels were sampled in February and April 2014, and processed for histological examination of several endosymbionts and pathogens that frequently occur in mytilid mussels. Endosymbionts and pathogens were not detected in farmed mussels. Prokaryotic inclusion bodies, the protozoan Nematopsis, Ancistrocoma-like ciliates, haplosporidian-like plasmodia, turbellarian Urastoma cyprinae, and basophilic inclusion bodies were observed in digestive gland cryosections of wild mussels from the coastal region of the northern Adriatic. Fungal spores of Psilocybe sp., Ulocladium sp. and Alternaria sp. were detected between the digestive tubules based on their morphology. Diagnostic PCR did not reveal infection with Marteilia refringens during the studied period, neither in wild nor farmed mussels. We confirmed the site effects on prevalence of infected mussels. Thus, we can conclude that wild areas are more exposed to endobionts and parasites than aquaculture sites.