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Human‐generated sound affects hearing, movement, and communication in both aquatic and terrestrial animals, but direct natural underwater behavioral observations are lacking. Baited underwater video (BUV) were deployed in near shore waters adjacent to Goat Island in the Cape Rodney–Okakari Point Marine Reserve (protected) or outside the reserve approximately four km south in Mathesons Bay (open), New Zealand to determine the natural behavior of Australian snapper Pagrus auratus exposed to motorboat sound. BUVs worked effectively at bringing fish into video range to assess the effects of sound. The snapper inhabiting the protected area showed no behavioral response to motorboat transits; however, fish in the open zones either scattered from the video frame or decreased feeding activity during boat presence. Our study suggests that motorboat sound, a common source of anthropogenic activity in the marine environment can affect fish behavior differently depending on the status of their habitat (protected versus open).

Marine protected areas (MPAs) have been recommended as an essential conservation tool for ecosystems and fisheries, with MPA coverage increasing four-fold globally since 2000. Despite the increased usage of MPAs, empirical results and scientists are divided on the effectiveness of MPAs to reach their conservation and management goals. In 2009, the South Atlantic Fishery Management Council established eight deep-water partially-protected MPAs off the southeast United States (SEUS) Atlantic coast with the goal of protecting long-lived, deep-water, reef-associated fishery species. Data collected during fish trapping from 2000 to 2018 as part of a fisheries-independent survey were used to evaluate the impacts of protection on a subset of fish species in three of these MPAs. There was a modest positive shift to larger fish observed in two of the MPAs and to older fish for one species, Pagrus pagrus (Linnaeus, 1758), in one of the MPAs relative to adjacent fished areas; however, there was either no change or a decrease in managed reef fish abundance in each MPA relative to adjacent fished areas. Based on these metrics, it does not appear that the SEUS MPAs have yet been effective at protecting managed reef fish species. Given that these MPAs have low enforcement, future assessments should examine compliance within the SEUS MPAs to determine if lack of success is due to illegal fishing, species examined, or MPA design before making a final determination if deep-water MPAs are an effective strategy for fisheries managers in the SEUS.

Metazoan parasite assemblages of Pagrus pagrus inhabiting the southwestern Atlantic were analysed with the aim of identifying the existence of different stocks and to comparatively assess the value of different parasite guilds asindicators of zoogeographical regions. A total of 186 fish was examined. Samples were obtained from three Brazilian and one Argentine localities, distributed in three different biogeographic districts of the Argentine Zoogeographical Province. Pagrus pagrus harboured 26 metazoan parasite species distributed in three guilds, ectoparasites (10 species), long-lived larval endoparasites and short-lived gastrointestinal endoparasites (eight species each). Prevalence and abundance values of the former two guilds allowed analysing them comparatively to assess their value as biological indicators of both host population structure and zoogeography. Results of analyses on longlived parasites evidenced the existence of three stocks, one in the regions of Rio de Janeiro and Sao Paulo, other in southern Brazil (Rio Grande do Sul) and a third in northern Argentina (Mar del Plata), responding to the differential environmental conditions characteristic of three zoogeographical ecoregions. Ectoparasite assemblages exhibited significant differences between all pairs of samples, including those considered as a single stock according to data on persistent parasites. Assemblages of long-lived larval parasites are considered as better indicators for stock assessment purposes than ectoparasites, whose population parameters were variable temporally and heterogeneous at small spatial scales. The distributional variability of persistent parasites of P. pagrus along large scales provides valuable information to help defining robust biogeographical patterns, applicable to stock identification and fishery management of this species. Fil: Soares, I. A.. Universidade Federal Rural Do Rio de Janeiro; Brasil Fil: Lanfranchi, Ana Laura. 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: Luque, J. L.. Universidade Federal Rural Do Rio de Janeiro; Brasil Fil: Haimovici, M.. Universidade Federal do Rio Grande do Sul; Brasil Fil: Timi, Juan Tomas. 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

Monitoring programs often collect presence− absence data to understand range ex pansions or contractions, metapopulation dynamics, alien species invasions, or spatial and temporal trends in relative abundance. Using the proportion of sites occupied by a species is misleading, however, if surveys routinely fail to detect species that are present. We used chevron traps paired with underwater videos (N = 1555) in a binomial (presence−absence) generalized additive modeling framework to quantify how environmental conditions, habitat characteristics, and the number of individuals at each site (i.e. site abundance) influenced the detection probabilities of economically important reef fish species in the southeastern USA. After accounting for variable site abundance, trap detection probabilities declined 40% for red porgy Pagrus pagrus, 65% for gray triggerfish Balistes capriscus, and 75% for vermilion snapper Rhomboplites aurorubens as percent hard bottom increased from 0 to 100%. Increasing water temperature caused red porgy trap de tection proba bility to decline modestly, while for gray triggerfish and vermilion snapper it increased substantially. Underwater video was more likely to de tect black sea bass Centropristis striata, red porgy, and gray triggerfish when site abundance and water clarity were high and the video camera was facing downcurrent. Using multiple gears simultaneously, we quantified the ways in which predictor variables influenced the sampling process, which will help in designing surveys that maximize detection probability. Our results also suggest that pairing video cameras to trawls, fisheries acoustics, or nets allows for the estimation of detection probabilities. Adding video cameras to fish traps can enable estimation of reef fish detection probabilities for each gear. Photos: Paul Ritter (left) and SEFSC, NOAA (right) FREE ACCESS

A high-resolution 3D biophysical model was used to investigate the patterns of larval transport for an important commercial and recreational temperate fish, snapper Pagrus auratus, from a well-established marine reserve (Cape Rodney to Okakari Point marine reserve, CROP), and spawning ground. Our focus was to study the effects of local hydrodynamics, contrasting larval vertical behaviours and changing El Nino-Southern Oscillation (ENSO) cycles (via their effect on wind forcing) on the potential larval supply to adjacent non-protected areas. The model suggests the CROP marine reserve provides significant larval subsidies within a relatively small scale (≤40 km), the details of which depend on larval behaviour and ENSO patterns. Changing ENSO patterns mostly affected the dispersal direction of larvae, while larval behaviour was a strong driver only under La Nina conditions. Modelling suggests that under El Nino conditions, snapper larvae are more likely to settle successfully and hence make a strong contribution to surrounding fished stocks. Understanding the contribution of MPAs to fisheries management will require multiple approaches. Modelling will help identify the strength of contributing physical and biological factors, and in due course enable site- and time-specific examples of larval subsidy to be generalised.

Status of fish stocks in relation to fishing may differ from one area to another, but there is a general consensus that several fish stocks need effective management measures by taking into consideration different indicators of stock status. Through a review of literature, this paper shows the importance of integrating the reproductive characteristics into the plan for management and conservation of marine fisheries as well as ecosystems. Overexploited fishes display symptoms of (i) advancements in age and/or size at sexual maturity and (ii) reduction in fecundity in gonochoristic (bisexual) fishes. Protogynic hermaphroditic fishes show symptoms of advancement in sex/age at sex change and decrease in Reproductive Life Span (RLS). Consequent to these changes in reproductive characteristics, the Spawning Stock Biomass (SSB) will decrease leading to depletion and collapse of a stock or species of fishes. In response to advancement in Age at Sexual Maturity (ASM) and/or Size at Sexual Maturity (SSM), the depleted stock/species may display one of the following symptoms: (a) decrease in fecundity, as in European hake Meruluccius meruluccius, or (b) decrease in egg size, as in Gadus morhua or (c) both decrease in fecundity and egg size, as in roughy Hoplostethus atlanticus. The protogynics economize male and sperm availability by behavioral acts like spawning aggregation; however, the longer residency of such spawning aggregation in a particular site increases the vulnerability of reproductively active parents. Analyses of limited publications show that (i) overexploitation reduces not only male biomass but also female biomass and (ii) reduction in RLS to 50% in Available online at: www.mbai.org.in doi: 10.6024/jmbai.2014.56.1.01750s-08 female e.g. Epinephelus niveatus and 33% in male e.g. Pagrus pagrus through precocious sexual maturity and sex change.

Marine environments require monitoring to determine the effects of impacts such as climate change, coastal development and pollution and also to assess the effectiveness of conservation measures. Marine protected areas (MPAs) are being established globally and require periodic monitoring to determine whether their objectives are being met. Baited underwater video systems are becoming a popular method for monitoring change within protected fish populations, because they are less damaging to habitats than bottom trawling and allow for more statistical powerful comparisons to determine spatial and temporal patterns in the relative abundances, lengths and biomass of demersal and pelagic fishes. However, much remains uncertain about how interactions between the fish and bait and between the fish themselves affect the results obtained. Agonistic behaviours are frequently observed around the bait of the camera and potentially bias fish density estimates by altering the number and size classes seen at cameras. Here we counted the number of agonistic behaviours between pink snappers (Pagrus auratus), the size of fish involved and whether the fish left the field of view following such behaviours. The study consisted of 20 baited underwater video deployments inside a New Zealand marine reserve and 20 in adjacent open areas. We observed a significant relationship between the peak number of fish observed at the camera and the total number of agonistic behaviours, as well as the number of both aggressor and subordinate fish leaving the camera field of view following interactions. The slope of the latter relationship and thus the absolute numbers of fish leaving were higher for subordinate fish. As subordinates were significantly smaller than aggressors, the apparent size frequency distribution is likely skewed away from smaller size classes. The staying time of the fish and thus the maximum number of fish present at the camera will be reduced by agonistic behaviours and the absolute magnitude of this effect appears to be greater at high fish densities. Our results suggest that an overall effect of these phenomena is to underestimate the differences in abundance between MPAs and open areas, but also to overestimate differences in average size.

In this work, we evaluated the effect of the probiotic Enterococcus gallinarum L-1 on the cellular immune system of four different fish species of great interest in aquaculture such as gilthead sea bream (Sparus aurata), European sea bass (Dicentrarchus labrax), meagre (Argyrosomus regius) and red porgy (Pagrus pagrus). Phagocytic activity, respiratory burst and peroxidase content of leucocytes were observed 30 minutes after incubation with the probiotic E. gallinarum strain L-1, alive or inactivated with heat shock or ultraviolet (UV) light at different concentrations of 107, 108 and 109 cfu mL−1 (final concentration 106, 107 and 108 cfu mL−1). E. gallinarum produced dose-dependent increments in respiratory burst in red porgy, sea bream and sea bass leucocytes. About 106 and 107 cfu mL−1 of live and inactivated bacteria with no stimulation of the respiratory burst activity of sea bream and red porgy head kidney leucocytes was shown. The highest values of peroxidase content were observed in red porgy cell...

A new technique to ameliorate the effects of barotrauma was tested based on observations of pink snapper, Pagrus auratus (Forster), inadvertently piercing their everted stomach with their teeth and releasing trapped swim bladder gases. This technique was termed buccal venting and involved piercing the everted stomach protruding into the buccal cavity or out of the mouth with a 16-gauge hypodermic needle (a practice previously not encouraged). Short-term (~3 days) survival of buccal-vented fish was not significantly different from laterally vented fish nor untreated controls. Both buccal and lateral venting techniques were shown to cause no harm and allowed fish to return to depth. The short-term (1–3 days) post-release survival of line caught snapper was 88% with no significant difference in survival across three depth ranges tested (37–50, 51–100 and 101–180 m). Survival of sublegal pink snapper ( 0.05) from that of legal-sized fish (≥35 cm TL). Healing of the swim bladder was observed in 27% of pink snapper dissected after ≤3 days in captivity, and healing of stomachs was observed in 64% of pink snapper that had been buccal vented. Relatively high post-release survival rates of line caught pink snapper may offer some protection for snapper stocks where high fishing pressure and legal size restrictions result in the majority of the catch having to be released.

Two trials were conducted to evaluate the nutrient digestibility of river crab (RC) ( Procambarus clarkii ) and marine crab (MC) ( Chaceon affinis ) meals in diets for red porgy ( Pagrus pagrus ) and the effect on ammonia-N excretion and P and Ca retentions. In trial I, the apparent digestibility coefficient (ADC) of nutrients and energy contents in RC and MC meals were determined. Results showed that, the ADC values for protein, lipids, ash, dry matter and gross energy were significantly higher for MC than for RC meal. Both crab meals were efficiently digested despite their high chitin and ash contents. In trial II, red porgy were fed over 6 months with five diets: a control diet (CD) based on high quality fish meal (FM), and four diets where FM protein was replaced at a rate of 10% or 20% by protein derived from either RC or MC meal (RC10, RC20, MC10 and MC20). Replacement of the FM protein by RC or MC proteins had no effect both on protein utilisation and ammonia-N excretion rates, which ranged from 105 to 119 mg N–NH 4 + kg − 1 day − 1 for all diets. A linear increase was observed in the dietary Ca/P ratio by the increase of the dietary RC and MC meal inclusions, resulting in a reduction in the whole fish body content of P, Ca and ash with interesting similar whole body Ca/P ratio (1.59–1.63) for all treatments. Accordingly, Ca, P and ash retention rates were significantly reduced by increasing the dietary proportion of both crab meals. Moreover, a negative relationship between fish growth and final whole body Ca, P and ash contents was obtained. However, no significant differences were observed in total P excretion value (kg P t − 1 ).

Snapper (Chrysophrys auratus) is an important coastal fish species in New Zealand for a variety of reasons, but the large amount of research conducted on snapper has not been reviewed. Here, we review life history information and potential threats for snapper in New Zealand. We present information on snapper life history, defining stages (eggs and larvae, juvenile and adult), and assess potential threats and knowledge gaps. Overall we identify six key points: 1. post-settlement snapper are highly associated with certain estuarine habitats that are under threat from land-based stressors. This may serve as a bottleneck for snapper populations; 2. the largest knowledge gaps relate to the eggs and larvae. Additional knowledge may help to anticipate the effects of climate change, which will likely have the greatest influence on these early life stages; 3. ocean acidification, from land-based sources and from climate change, may be an important threat to larval snapper; 4. a greater understanding of population ...

Management of fish populations is often focused on the exploitation of adult fish. Maintaining the habitat requirements of all life stages may also be an important consideration. We investigated the value of structured habitat to juvenile fishes within a northeastern New Zealand harbour using artificial seagrass units (ASUs). Specifically, we deployed ASUs across treatments with high vs. low habitat manipulations. We hypothesised that if the abundance of recruiting juvenile fishes was greater on the high habitat availability treatments this would suggest that the availability of habitat was limiting juvenile fish abundance. Our analyses were focused on the four most abundant fishes that settled on our ASUs: snapper (Pagrus auratus); spotty (Notolabrus celidotus); trevally (Pseudocaranx dentex); and an assemblage of pipefish species. For snapper, spotty and pipefish, abundance was greater on the high habitat availability treatments. This result would be unlikely to occur if the availability of juvenile fis...

The mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming-up hypothesis (i.e., the increase in the production of high-trophic-level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming-up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming-up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low-trophic-level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds.

This review examines the history and current understanding of the ecology of rocky reef fishes in northeastern New Zealand, marking the fiftieth anniversary of the Leigh Marine Laboratory. The cumulative number of publications increased steadily to c. 180 by 2012. Most attention has been on the snapper (Pagrus auratus, f. Sparidae), the largest in size and economically most important species, and on triplefins (Tripterygiidae), the smallest in size and most diverse family. A strong quantitative school emerged in the 1980s, a period when there was little research on temperate reef fishes elsewhere. A ‘bottom-up’ view of the effects of habitat structure on fish emerged, identifying the key roles of depth, topography and macroalgae. By 2000, attention shifted to using marine reserves as laboratories for ecological research. A ‘top-down’ view of fish as predators emerged, documenting cascading effects on prey communities and habitats. The two different viewpoints have not yet been integrated. Researc...

We investigated the effect of environmental hypoxia on vision in snapper (Pagrus auratus). Juvenile snapper inhabit estuarine environments where oxygen conditions fluctuate on a seasonal basis. Optomotor experiments demonstrated that visual acuity is impaired by environmental hypoxia, but not until levels approach the critical oxygen tension (Pcrit) of this species (around 25 % air-saturated seawater). In 100, 80, and 60 % air-saturated seawater, a positive optomotor response was present at a minimum separable angle (MSA) of 1°. In 40 % air-saturated seawater, vision was partially impaired with positive responses at MSAs of 2° and above. However, in 25 % air-saturated seawater, visual acuity was seriously impaired, with positive responses only present at MSAs of 6° and above. Snapper were found to possess a choroid rete, facilitating the maintenance of high ocular oxygen partial pressures (PO2) during normoxia and moderate hypoxia (PO2, between 269 and 290 mmHg). However, at 40 and 25 % water oxygen saturation, ocular PO2 was reduced to below 175 mmHg, which is perhaps linked to impairment of visual acuity in these conditions. The ability to preserve visual function during moderate hypoxia is beneficial for the maintenance of a visual lifestyle in the fluctuating oxygen environments of estuaries.

We studied the morphological development, allometric growth, and cannibalistic behavior of Red Porgy Pagrus pagrus reared in mesocosm semi-intensive culture. The study was conducted from hatching to 32 d after hatching (DAH). Red porgy ontogeny was characterized by strong positive allometric growth of body depth at anus (BDA) to 6.7 mm total length (TL) at about 21–22 DAH. The BDA combined with standard length (SL) in a morphometric index was found to be better correlated with dry weight than TL and provided an improved method to estimate larval growth. Mouth size also exhibited strong positive allometric growth at early larval stages that, together with inflation of the swim bladder, may have contributed to improve feeding ability, in preparation for the high energy demands of metamorphosis. A predictive regression model developed for cannibalism underestimated prey size. Cannibalism coincided with the development of acidic digestion and was first evident at 27 DAH as larvae reached about 23% of...

This study investigated the inter- and intra-annual variation in the spawning dynamics of snapper (Chrysophrys auratus). Reproductive samples from northern Spencer Gulf, South Australia were collected over three seasons (2005/06, 2006/07 and 2007/08) and were analysed macro and microscopically. Spawning activity was determined by calculating estimates of spawning fraction and batch fecundities. The onset of spawning occurred in November but varied between years and corresponded with times when water temperature was between 18 °C and 20 °C. The length of the spawning season also differed between years. In each year the peak spawning activity occurred during December when fish spawned almost daily. Spawning frequency and relative batch size did not differ between the first two spawning seasons but, in the third season, batch size was considerably greater and spawning fractionally lower. These results are contrasted with a known recruitment of 0+ over the three years of the study.

This study was done to determine if fortification of a commercial aquafeed with KCl could improve the survival of juvenile Australian snapper Pagrus auratus reared in K+ deficient saline groundwater (KDSGW, &lt, 5 mg K+ L−1). Experiment 1 (Exp. 1) tested whether feeding an aquafeed fortified with zero, 25, or 50 g KCl kg−1 for 6 days affected feed intake and survival of fish transferred immediately from estuarine water to KDSGW of the equivalent salinity (20 g·L−1). Experiment 2 (Exp. 2) investigated whether an aquafeed fortified with zero, 10, or 25 g KCl kg−1 affected survival, feed intake, and growth rate (SGR) of snapper reared in KDSGW fortified to have 40% or 100% the [K+] of equivalent salinity estuarine water (20 g·L−1). The results of Exp. 1 demonstrated there was no benefit of fortifying aquafeed with KCl, fish transferred into KDSGW stopped feeding and developed symptoms akin to tetany. Some individuals also died and others became moribund. Exp. 1 was terminated according to animal care and ethics guidelines. The results of Exp. 2 indicated the amount of KCl added to the aquafeed did not affect survival, feed intake, or food conversion ratio (FCR) of snapper, irrespective of water treatment. However, SGR and FCR was better when fish were reared in normal estuarine water and KDSGW fortified to have 100% the [K+] of equivalent salinity estuarine water. Our results demonstrated that juvenile snapper were unable to utilize the KCl added to the aquafeed and were probably reliant on sequestering K+ ions from the water column in order to maintain functions involving hydromineral homeostasis. Fortification of aquafeeds with KCl does not ameliorate the negative effects of KDSWG on the survival of juvenile snapper.

Marine fish abundance and distribution often varies across spatial scales for a variety of reasons, and this variability has significant ecological and management consequences. We quantified the distribution of reef-associated fish species along the southeast United States Atlantic coast using underwater video survey samples (N = 4,855 in 2011–2014) to elucidate variability within species across space, depths, and habitats, as well as describe broad-scale patterns in species richness. Thirty-two species were seen at least 10 times on video, and the most commonly observed species were red porgy (Pagrus pagrus; 41.4% of videos), gray triggerfish (Balistes capriscus; 31.0%), black sea bass (Centropristis striata; 29.1%), vermilion snapper (Rhomboplites aurorubens; 27.7%), and red snapper (Lutjanus campechanus; 22.6%). Using generalized additive models, we found that most species were non-randomly distributed across space, depths, and habitats. Most rare species were observed along the continental shelf break, except for goliath grouper (Epinephelus itajara), which was found on the continental shelf in Florida and Georgia. We also observed higher numbers of species in shelf-break habitats from southern North Carolina to Georgia, and fewer in shallower water and at the northern and southern ends of the southeast United States Atlantic coast. Our study provides the first broad-scale description of the spatial distribution of reef fish in the region to be based on fishery-independent data, reinforces the utility of underwater video to survey reef fish, and can help improve the management of reef fish in the SEUS, for example, by improving indices of abundance.

Diel variation is known to alter the composition and structure of reef fish assemblages. What is unknown is how nocturnal fish assemblages respond to closed fishery area management. Diurnal and nocturnal reef fish assemblages at the Houtman Abrolhos Islands, Western Australia, were studied using baited remote underwater stereo-video systems (stereo-BRUVs). Surveys were conducted during the day and at night (using blue illumination) from three sites inside and three sites outside a closed fishery area (CFA). The relative abundance of 116 fish species from 41 families was recorded. Significant changes were observed in fish assemblage structure from day to night (driven by high dispersion at night) and in areas open versus closed to fishing (driven by increased abundance within the CFA). The effect of protection from fishing was consistent for both diurnal and nocturnal fish assemblages. Closer examination of six targeted fish species showed that their response to diel changes and the absence of fishing pressure varied from species to species. The targeted fishes Pagrus auratus and Glaucosoma hebraicum were sampled during the day and at night with both species responding positively to protection from fishing. Results suggest that the inclusion of diurnal and nocturnal fish assemblage data will provide an improved ability to assess the effectiveness of closed fishery area management.

SUMMARYEffective spatial management of marine species requires informed planning, as well as ongoing assessment. For mobile species such as fish, knowledge of the scale and variation in movement is central to key planning decisions, such as the size and shape of marine reserves and the interpretation of the response of protected populations. For example, populations of species that require large areas of habitat may not show increases in abundance inside small reserves, but calculating optimal reserve size is complicated by individual variations in behaviour. Fish movements can be used to quantitatively inform marine reserve planning and assessment. An individual based numerical simulation model including acoustic telemetry and census data was used to simulate changes in populations of snapper Pagrus auratus in north-eastern New Zealand. Four behavioural categories and offshore migration were used to represent the observed variability in movement. Age-structures of modelled fish populations in fully exploited areas, marine reserves and virgin populations differed substantially. However, the population structure within reserves resembled a fully fished population more closely than an unfished population. Due to the range of movement types shown by snapper, fish were not ‘locked up’ by reserves, and fish with centres of activity based in reserves were predicted to have a relatively high chance of being caught outside these reserves. Furthermore, the model showed that the response of fish populations within marine reserves was dependent on levels of exploitation in fished areas. For snapper in coastal reef areas, reserves c. 40 km2 or more may be required to achieve abundances > 50% of the unfished stock. On balance, while marine reserves with sizes similar to Leigh and Tawharanui (c. 5 km2) can achieve significant levels of protection for snapper, they are too small to fully protect resident reserve snapper populations.

Three species of Kareniaceae, Karenia brevis, Karenia brevisulcata and Karenia mikimotoi were assessed for toxicity to juvenile Chinook salmon (Oncorhynchus tshawytscha), snapper (Pagrus auratus) and six species of marine invertebrate larvae (GreenshellTM mussel, pacific oyster, paua [New Zealand abalone], sea slug, sea urchin and brine shrimp). Karenia brevis was ichthyotoxic to juvenile salmon with a LT50 of 0.75 h at 0.18 × 106 cells L–1 but juvenile snapper were less sensitive (LT50 of 4.5 h at 5.9 × 106 cells L–1). Karenia brevisulcata also showed differential toxicity to juvenile salmon and snapper with LT50 of 0.48 h at 11 × 106 cells L–1 and 7.5 h at 16 × 106 cells L–1 respectively. However, no acute symptoms were observed in the fish following 48 h exposure to K. mikimotoi at 3.4 × 106 cells L–1. Karenia brevis at the highest level tested (8.7 × 106 cells L–1) did not cause observable symptoms in any of the invertebrate larvae over 24 h. Karenia mikimotoi only affected paua larvae (LT50 ...

Red porgy, Pagrus pagrus, is a candidate species for aquaculture diversification. The aim of this work was to assess whether an early supply of enriched Artemia (D1) or a direct step to dry diets (D3) would be advantageous weaning strategies for red porgy larvae, compared to a later supply of Artemia followed by dry diets (D2). Direct weaning to dry diet resulted in significantly lower growth, survival, pancreatic (trypsin and lipase), and intestinal (alkaline phosphatase) enzyme-specific activity, with the exception of leucine-alanine peptidase. The direct weaning strategy presented severe nutritional restrictions from early weaning stages with an associated delay of the maturation of digestive system. The two-step strategy presented in D1 and D2 resulted in comparable results in most parameters, including survival. Weaning using enriched Artemia as an intermediate step is confirmed as the most adequate strategy for red porgy larvae. Digestive enzymes and selected fatty acids correlated well with performance responses to dietary regimes, thereby supporting the use of these parameters as sensitive and reliable indicators of red porgy nutritional or physiological status during larval stages.

Fish communities associated with a series of artificial reefs deployed in three estuaries in southeastern Australia (151° 34′ E, 33° 7′ S to 150° 37′ E, 35° 8′ S) were surveyed using both Baited Remote Underwater Video (BRUV) and Underwater Visual Census (UVC). Abundance estimates, frequency of observations, and species indicators (richness and diversity) provided the basis for comparison between methods. UVC recorded significantly greater numbers of species in all estuaries and significantly greater species richness and diversity at two of the three estuaries. Variation in the number and frequency of species detected by each method directly related to the ecological niche and behaviour of each species. UVC provided better estimates of the rare or cryptic reef associated species. BRUV sampled a smaller proportion of species overall but did observe key recreational species such as Acanthopagrus australis , Pagrus auratu s and Rhabdosargus sarba with increased frequency, although the presence of large numbers of schooling species such as Pelates sexlineatus reduced the detection frequency of these species. In summary, results indicate that BRUV is an effective method for recording species associated with artificial reefs with the exception of cryptic species that are located within the reef structure itself. BRUV techniques complement UVC by providing increased coverage of species known to be diver averse as well as providing important information regarding behaviour of the species identified. Given the limitation of each method, it is recommended that monitoring plans for artificial structures should adopt a multi-method approach utilising BRUV and UVC where possible.

Socio-economic factors related to management of costal zones and biological parameters related to species-specific requirements set limitations for the rearing location of net-pen sea cages. A cage was designed and installed at 45 m depth based on the REFA Tension Length Cage technology at the cage facility of the Hellenic Centre for Marine Research in Crete. The cage-net module consisted of a net-pen contained within a hexagonal rigid frame to maintain the shape of the net. Vertical beams of the frame glider on six tension legs were placed in a circle. The operation of the cage was evaluated using ag roup of red porgy (Pagrus pagrus) for a rearing period of 4 months whereas a second group reared in a surface net-pen cage served as control. Growth performance was similar between the experimental groups. The rearing method significantly affected fish skin pigmentation. Individuals reared in the submerged cage had a brighter skin colour and lower skin melatonin content compared with the ones reared in the surface cage. The presented submerged cage may provide a feasible alternative for rearing fish in exposed areas and particularly species requiring specific biological conditions, such as narrow temperature ranges and low light intensity.

The diet of the sparid fish Pagrus auratus (snapper) was examined within the Mahurangi Harbour in north-eastern New Zealand. Ontogenetic shifts occurred in diet. Individuals 100 mm consumed brachyuran crabs, caridean shrimps, bivalves, polychaetes and hermit crabs, with individuals >300 mm also able to consume harder shelled molluscs and bivalves. The stomach contents of juvenile snapper (10–100 mm) sampled across habitats of sand, shell hash, horse mussels and subtidal mud showed differences in major prey taxa; however, these differences were small. This may be advantageous for juveniles, which can then select a habitat for other qualities. A comparison with eight other studies on the diet of snapper from coastal areas showed crustaceans were consistently the most highly ranked major taxon; however, differences among other major taxa were relatively minor.

We used a maximum-count aerial-access survey design to estimate the 12-month recreational harvest of snapper Chrysophrys (Pagrus) auratus (also known as squirefish) taken by New Zealand's largest recreational fishery. To provide a count of all boats fishing on a given day, the spatial extent of the 3,800-km2 Hauraki Gulf embayment was surveyed from the air on a random stratified selection of survey days at the approximate time of maximum effort. Anglers were also censused at a subset of the available access points on the same day. The ratio of the aerial count to the number of interviewed parties who claimed to have fished at the time of the overflight was used to expand the observations of landed catch and to estimate the total catch taken by all fishers returning to all access points. Pairing an aerial count with a creel-survey-derived profile of effort on each survey day provides two advantages. First, only one flight is required to estimate the overall level of effort on each day, which is be...

Local ecological knowledge is a potentially valuable, but mostly untapped, resource for evaluating decadal-scale shifts in abundances of organisms. In this study, recollections of long-term divers were quantified to assess changes in underwater life at the Poor Knights Islands in temperate northeastern New Zealand from the 1960s to 2000s, in order to establish baselines for recovery since the islands were protected within a no-take marine reserve in late 1998. Data were validated against quantitative data from contemporary monitoring programmes (established in the late 1990s), with the divers conservative in that their reported changes were smaller than those from the scientific monitoring. The divers reported large (60–88%) and steady long-term declines in abundances of black corals (Lillipathes lilliei), tube sponges (Calyx imperialis), packhorse lobster (Sagmariasus verreauxi), and several large predatory fishes. There was little or no suggestion of recent recovery in these species following no-take protection. Only the sparid fish Pagrus auratus and sharks were considered to have substantially increased in numbers following no-take protection. Multivariate analysis of data derived from the divers’ recollections detected no signs of recovery at the community-level, although full no-take protection appeared to have stopped further change along the major axis of variation. Our results highlight the value of local ecological knowledge for investigating decadal-scale changes in reef biota and for providing a longer-term context for evaluating the efficacy of marine reserves.

The feeding performance and behavior at the onset of exogenous feeding, 3 to 4 days after hatching (DAH), were studied in red porgy Pagrus pagrus larvae. Similar feeding efficiency and intensity were achieved for two feeding treatments (live or freeze-dried rotifers) suggesting that prey movement is not decisive for their detection and capture and demonstrating that at first feeding red porgy larvae can ingest inert food. Larvae feeding performance was not affected by a diet shift between treatments. Based on maximum rotifers consumption and gut evacuation time at 18 °C, the daily ration was estimated as 14.035 μg, considering 14 h of feeding and a 25% egg:female rotifer ratio. Larval swimming activity measured by video recording showed a close association with gut fullness and similar swimming patterns for 3 and 4 DAH larvae. However, 20.3% larger mouth gape and 54.6% higher swimming speed of the older larvae should provide a better feeding performance and more energy needed for growth.

Atlantic red porgy, Pagrus pagrus, is an important reef fish species in the Mediterranean and the snapper–grouper complex off the southeastern United States. Red porgy is a viable candidate for aquaculture with high market value and the ability to spawn freely in captivity. The objective of this study was to examine the combined effects of temperature and salinity on eggs, yolk-sac larvae, and early feeding-stage larvae of red porgy to day 16 post-hatching (d16ph). To determine the optimal temperature and salinity conditions for culture, embryos were reared under four temperatures (17, 19, 21, and 23 °C) and two salinities (24 and 34 g/L) in a 4 × 2 factorial design. Significant effects of temperature and salinity on growth (notochord length, wet and dry weight), survival, whole body osmolality, and expression of Na+/K+ ATPase were observed with minimal interactive effects. Under both salinities, growth increased with increasing temperature. On d16ph, wet weights at 21 and 23 °C (2.03 and 2.91 mg, respectively) were significantly higher than at 17 and 19 °C (0.20 and 0.69 mg). Salinity had no effect on growth at any temperature, but had a significant effect on survival to d16ph, with greater survival at 24 g/L (18.4%) than at 34 g/L (6.77%). Salinity significantly affected whole body osmolality on d2ph and d11ph, with 24 g/L having lower whole body osmolality than 34 g/L on both days. Temperature significantly affected whole body osmolality on d6ph, with no clear trends and on d17ph, with 17 °C (534 mOsm/kg) higher than all the higher temperatures (396–411 mOsm/kg). After increasing each tank to 44 g/L to create a sublethal salinity challenge on d16ph, larvae from 34 g/L treatments did not show an increase in levels of Na+/K+ ATPase mRNA after 24 or 48 h post transfer. However, fish in the 24 g/L treatments showed a significant increase in expression of Na+/K+ ATPase mRNA after 24 h followed by a decrease after 48 h. Within the ranges tested, a temperature of 23 °C and a salinity of 24 g/L appear to be optimal for culture of red porgy embryos, yolk-sac, and first-feeding stage larvae to d16ph.

Despite the long history of the development of artificial structures in NSW estuaries there are no studies that provide any comprehensive scientific evaluation of post-deployment goals. We assessed the effectiveness of estuarine artificial reefs as a fisheries enhancement initiative; described the diversity and abundance of species associated with them, and detailed the patterns of colonization and community development associated with an artificial reef deployment in Lake Macquarie, a large coastal barrier lagoon on the southeast coast of Australia. Six artificial reefs (one artificial reef group), constructed from artificial reef units (Reef Balls®), were deployed in December 2005 and sampled six times per season over two years using baited remote underwater video (BRUV). Colonization of the artificial reef group was relatively rapid with the majority of species identified over the two-year study period observed within the first year post-deployment. Overall, 27 species from 17 families were identified. Key colonising species included Pelates sexlineatus (Terapontidae), Acanthopagrus australis (Sparidae), Pagrus auratus (Sparidae) and Rhabdosargus sarba (Sparidae). Species richness showed evidence of potential seasonal fluctuations, being higher in warm water months (Summer/Autumn), and lower in the colder water months (Winter/Spring), while species diversity increased significantly with reef age. Fish assemblage composition remained relatively stable after the first year of sampling, with few discernible patterns in assemblage structure evident after the first year. Distinct separation in reef age groupings was evident during the second year of sampling; a pattern primarily driven by a decrease in abundance of P. sexlineatus, a result of the isolated nature of the artificial reefs and the interrelated effects of density dependence and predation.A despeito da longa história do desenvolvimento de estruturas artificiais nos estuários de NSW, não existem estudos que apresentem uma avaliação global sobre os efeitos obtidos com o estabelecimento dessas estruturas. No presente trabalho abordamos a efetividade dos recifes artificiais estuarinos como iniciativa para aumento da pesca; descrevemos a diversidade e abundância das espécies a eles associadas; descrevemos os padrões de colonização e o desenvolvimento das comunidades associadas a um recife artificial colocado no Lago Macquaire, extensa lagoa de barreira situada na costa sudeste da Australia. Seis recifes artificiais (formando um único grupo), construídos a partir de unidades artificiais (Reef Balls®), foram lançados em Dezembro de 2005 e amostrados seis vezes a cada estação do ano, durante dois anos, utilizando video subaquático remoto (BRUV). A colonizaç��o dentro do grupo de recifes ocorreu de maneira relativamente rápida, sendo que a maioria das espécies identificadas nos dois anos de estudo foi observada durante o primeiro ano de amostragem. Um total de 27 espécies pertencentes a 17 famílias foram identificadas. As espécies chave do processo de colonização foram Pelates sexlineatus (Teraponidae), Acanthopagrus australis (Sparidae), Pagrus auratus (Sparidae) and Rhabdosargus sarba (Sparidea). A riqueza de espécies mostrou evidência de sazonalidade, enquanto a diversidade aumentou significativamente com o aumento da idade do recife. A composição da assembléia de peixes permaneceu relativamente estável após o primeiro ano de amostragem, com poucos padrões identificáveis relativos à estrutura. Durante o segundo ano tornou-se evidente a formação de grupos por idade, padrão primariamente ocasionado pelo decréscimo na abundância de P. sexlineatus; por sua vez este decréscimo mostrou ser resultado da natureza isolada do recife artificial e dos efeitos interdependentes de abundância e predação.

Red porgies (Pagrus pagrus )o f 20.6� 1.5 g mean weight were reared in tanks under four delayed selffeeding conditions (0 5 control, 7, 30 and 90 s) after rod activation. The time intervals were chosen to simulate the time taken for a commercial pelleted feed to transit the tube linking a surface-mounted feed hopper and the depth at which a cage might be submerged. Daily feeding rate, growth, food conversion index and condition factor were quite similar but ¢sh behaviour diiered among conditions. Fish remained close to the feeding point in the ¢rst two treatments (0 and 7 s delay) but foraged more widely in the remaining treatments (30 and 90 s delay), only reconsolidating around the feeding point a few seconds before feed was released. Results are discussed in relation to learning capacity and adaptation of ¢sh to feeding behaviour £exibility, in order to develop reliable self-feeding systems suitable for submerged cages.

Quantifying the movement of exploited species inside marine reserves is a popular research topic, yet few studies have quantified movement inside and outside of reserves. If individuals inside reserves behave differently to those outside, this information should be incorporated into reserve design and in management efforts to avoid the selective removal of certain behaviors. We used acoustic telemetry to monitor the movements of the sparid Pagrus auratus (snapper) inside and outside a marine reserve (the Leigh Marine Reserve, north-eastern New Zealand). We tagged 39 snapper within an array of acoustic receivers that encompassed reserve and fished areas. Nineteen snapper were resident over a 5-month period; the remainder either left the array or died. Residential fish expressed two home range types. One group had uni-modal home ranges that on average encompassed c.900 m linear distance. All nine residential snapper from the reserve displayed this behavior, as well as five of ten residential fish from the non-reserve area. The second group (five fish, all from the non-reserve area) had home ranges with two separate modes (bi-modal home ranges), which on average encompassed c.2 100 m linear distance. We suggest that some aspect of the marine reserve environment encourages extreme residency by either the modification of individual behaviors or through the removal of selective exploitation. If true this suggests that reserves and populations of exploited animals may become dependent on the life history characteristics of the individuals they encourage or select for.

Life history characteristics of snapper (Pagrus auratus) were found to vary at fine spatial scales (less than tens of kilometres) in the sub-tropical waters of Shark Bay, Western Australia, from research undertaken between 1997 and 2004. Differences in the timing and duration of the spawning season, length and age at maturity, and maximum age and growth between snapper from the Eastern Gulf, Denham Sound and Freycinet Estuary were attributed to spatial differences in environmental conditions and density-dependent responses to fishing-induced changes in spawning biomass. Such fine-scale spatial variation in the biological characteristics of snapper is consistent with results of previous stock identification studies and further supports the geographic scale at which local snapper stocks are managed to protect both stock productivity and genetic diversity.

Snapper, Pagrus auratus (Forester), is an important recreational species in marine waters of Victoria, Australia. This study estimated survival for compulsorily released undersized P. auratus by holding fish in cages and tanks for 3 days. In all, 620 P. auratus caught by angling were assessed for post-release survival and 200 additional fish were used as controls. The survival rate was greater for shallow-hooked (97%) than deep-hooked (48%) P. auratus. Post-mortems showed that hooking injuries to the throat and/or gill area caused most deaths, while piercing of the heart also caused mortalities. Removing deeply ingested hooks decreased survival. To estimate survival of P. auratus across the Victorian fishery, this study’s results should be combined with estimates of shallow-hooking rates in the fishery. Shallow-hooking rate estimates would quantify the impact of the low survival rate found for deep-hooked fish.

Katsanevakis, S., Maravelias, C. D., and Kell, L. T. 2010. Landings profiles and potential métiers in Greek set longliners. – ICES Journal of Marine Science, 67: 646–656. A very large number (>14 000) of generally small vessels operate as longliners in Greek seas. The aim of this study was to identify potential set longline métiers, based on a large sample of landings records from all over Greece. Landings data from set longliners between 2002 and 2006, collected from several ports in the Aegean and East Ionian Sea, were used. The landings profiles were grouped using a two-step procedure, the first involving factorial analysis of the log-transformed landing profiles, and the second a classification of the factorial coordinates (hierarchical agglomerative clustering). In all, 13 métiers were identified in the Aegean Sea and 7 in the Ionian Sea. The most important métiers identified were those targeting white sea bream (Diplodus sargus), hake (Merluccius merluccius), common sea bream (Pagrus pagrus), and common pandora (Pagellus erythrinus), and mixed métiers. Varying spatial (within the Aegean and Ionian Seas) and seasonal patterns were evident for the métiers identified, indicating that fisher motivation to engage in a specific métier varies both spatially and temporally.

Anecdotal data sources may constitute an important component of the information available about an exploited species, as record keeping may not have occurred until after exploitation began. Here, we aimed to fill any gaps in the exploitative history of the sparid snapper (Pagrus auratus), using social and historical research methods. Social research consisted of interviews with recreational fishers, focusing on the most and largest snapper they had caught. In addition, the diary‐logs of two recreational fishers were analysed. Historical research consisted of investigation of old books, photos, archives and unpublished sources unconventional to fishery science. Interviews with fishers demonstrated no or weak trends in snapper abundance or size, and were likely impeded by a lack of ability to detect change in a fish stock that may still be considered abundant. The fishers’ perception of change, however, largely reflected recent experiences (last c. 10 years), when biomass is understood to have incr...

In this study, heritabilities for body composition traits, their genetic correlations with growth traits and the genotype–environment interaction (G × E) were estimated at 509 days (harvest size) for the first time in gilthead seabream ( Sparus auratus L . ), from the offspring in two different production systems (cages and tanks) in the Canary Islands. A total of 867 offspring from an industrial mass-spawning of 66 broodstocks were analysed. Parental assignment showed a total of 89 full-sib families (between 1 and 53 descendents per family) and was inferred using the RimA multiplex PCR designed by Navarro et al. (2008) [Navarro, A., Badilla, R., Zamorano, M.J., Pasamontes, V., Hildebrandt, S., Sanchez, J.J., Afonso, J.M., 2008. Development of two new microsatellite multiplex PCRs for three sparid species: gilthead seabream ( Sparus auratus L.), red porgy ( Pagrus pagrus L.) and redbanded seabream ( P. auriga , Valenciennes, 1843) and their application to paternity studies. Aquaculture 285, 30–37.] with 100% success. The G × E interaction was analysed in 61 families present in the two environments and was null for visceral fat and it cannot be excluded for flesh composition traits. The heritability for visceral fat, expressed as a percentage of body weight, was 0.50 ± 0.07. The heritabilities for flesh composition traits, expressed as a percentage of fresh muscle weight, were 0.05 ± 0.03 for fat, 0.09 ± 0.03 for moisture, 0.08 ± 0.03 for ash and 0.02 ± 0.01 for collagen. Genetic and phenotypic correlations among body composition traits were mainly low–medium, except for moisture vs. muscular fat (− 0.98 and −0.61, respectively), moisture vs. collagen (0.85 and 0.45, respectively), collagen vs. muscular fat (− 0.80 and −0.35, respectively), and dressing percentage vs. visceral fat (− 0.92 and −0.51 respectively). Genetic correlations between body composition traits and growth traits were low for weight and length except with collagen for which they were high, and, in general, they were medium–high for condition factor. All these phenotypic correlations were low. These data suggest that selection through growth would improve flesh texture, but could decrease muscular fat in the long term. The latter trait could be improved by selection through moisture which is the flesh composition trait with the highest heritability and is the easiest to measure. The data also suggest that the inclusion of visceral fat percentage in a selection programme would thwart the negative effect of fat concentrated in the visceral cavity and increase the dressing percentage.

The effects of fishing and protection on the length of targeted and non-targeted warm- temperate and tropical reef fishes were studied using baited remote underwater stereo-video cameras at the Houtman Abrolhos Islands, Western Australia. Video images were obtained from inside a marine protected area (MPA) and from 3 replicate fished locations within each of 3 island groups. The effects of protection on the lengths of 6 targeted and 4 non-targeted fish species were examined. Five of the 6 targeted fish species were larger inside MPAs than in areas open to fishing (Choerodon rubescens, Lethrinus miniatus, Lethrinus nebulosus, Pagrus auratus and Plectropomus leopardus). Targeted species were, on average, 48 mm (10%) larger inside MPAs than in areas open to fishing. The vast majority of the individuals of C. rubescens, P. auratus and P. leopardus recorded were smaller than their minimum legal size for first capture. For non-targeted species, only 1 of the 4, Coris auricularis, showed an effect of protection, with the mean length of individuals reduced by 85 mm (33%) inside MPAs relative to areas open to fishing. This study demonstrated clear effects of protection from fishing on the size structure of populations of common warm-temperate and tropical reef fishes.

Despite being proposed as a potential candidate for diversification of marine aquaculture, limited larval survival and the occurrence of elevated levels of skeletal deformities restrict the commercial production of red porgy. The present study was conducted to determine the effect of rotifer enrichment, particularly on DHA, on growth, survival and occurrence of skeleton deformities in this species. The study included two trials, in one the viability of commercial emulsions for rotifer enrichment was evaluated whereas in another the effect of the elevation of DHA in rotifer emulsions on the larvae was studied. No significant differences were found in growth between larvae fed different rotifers in both trials suggesting that 1.9% dw DHA is enough to fulfil the DHA requirements of red porgy larvae for maximum growth. However, a marked positive effect of rotifer DHA content supplementation on larval survival was found. A low larval survival was found when rotifers had a high DPA content, in agreement with the results obtained for other Sparids. This fatty acid was accumulated in red porgy larval tissues in high levels (0.79% dw DPA) when rotifers rich in DPA were the main source of food. Although the external appearance of the juveniles seemed to be normal, X-ray observations showed elevated levels of bone abnormalities associated, in both trials, to low DHA content in the live prey. Among different anomalies, the presence of fused vertebrae was the most frequent deformity for both rearing trials. Although DHA content in the rotifers used for feeding was the only difference a 50% reduction in the number of deformed fish for each type of deformity studied was obtained when the larvae fed higher DHA levels, denoting the important role of this FA in the prevention of deformities at the rotifer feeding stage. Further studies are needed to elucidate the importance of essential fatty acids on the development of bone deformities in fish, since the functions of HUFA are different, and their absolute levels and ratios among them can lead to very different effects in fish metabolism, including bone formation.

A 10-year bottom longline survey and a smaller scale hook-and-line survey were used to study how habitat and fishing might affect the population structure of red porgy ( Pagrus pagrus ) at various scales in the archipelago of the Azores, central north Atlantic. The size and sex of fish caught responded to local factors rather than fishing or larger scale (geographic) factors. Young-of-the-year red porgy recruit to shallow, sandy habitats located inshore, and apparently migrate toward deeper and progressively rockier bottoms. This pattern seems to explain why red porgy are only found around the islands’ shores, being absent from shallow seamounts where suitable adult habitat exists but juvenile habitat is absent. The probability of sex-change was higher in sites whenever abundance was low. Significant large-scale differences among islands may well be attributable to exploitation, as the lowest abundances were consistently found off islands subject to higher fishing efforts. We also found some evidence of positive effects on porgy abundance and biomass from a 4-year ban on inshore longline fishing, but such benefits lack further (temporal) evidence. Recruitment to the fishery varied twice by an order of magnitude during the 10-year longline monitoring period, reflecting also high natural variability. These findings highlight the need to explicitly include the habitat essential for growth and, eventually, the presence of adequate ontogenic migration corridors when devising schemes of spatial management of red porgy populations, including marine reserves.

Red porgy Pagrus pagrus, scamps Mycteroperca phenax, and gags M. microlepis support valuable recreational and commercial fisheries in North Carolina. Fish in the snapper–grouper complex are managed to prevent overfishing and maintain a stable spawning stock. We investigated postrelease mortality of 263 undersized red porgy, scamps, and gags that were captured by angling and subjected to short-term (2 h) and long-term (48 h) holding experiments. Fish were caught at depths ranging from 15 to 45 m using traditional bottom-fishing hook-and-line gear. Catch per unit effort ranged from 0.11 to 1.80 fish/rod-hour (FRH) for sublegal-sized fish and from 0.06 to 0.50 FRH for legal-sized fish. Nontarget species predominated in the catch (N = 1,135), but the red porgy was the most frequently caught individual species (N = 196). The effects of short-term (2-h) holding within species were similar between fish held in different locations (oxygenated live well or cage anchored to the seafloor); mortality did not...

The effect of rapid transfer of juvenile Australian snapper, Pagrus auratus from ambient seawater (30‰) to concentrated hyperosmotic (45‰) and diluted hyperosmotic (15‰) environments on serum osmolality, serum [Na+], [K+], [Cl−], blood haematocrit and branchial chloride cell morphology was assessed during 168 h after transfer. Serum osmolality, [Na+], [K+] and [Cl−] increased after 24 h in 45‰. In contrast, after 24 h in 15‰, [K+] did not change but serum osmolality, [Na+] and [Cl−] decreased. The serum chemistry changes were transient and had returned to near initial levels after 168 h in 45‰ and 15‰. Transfer from 30‰ to 45‰ and 15‰ did not affect blood haematocrit. Branchial chloride cells were identified in both filament and lamellar epithelia of snapper held in all salinity treatments by an immunocytochemical staining technique using an antiserum specific for Na+, K+–ATPase. In 45‰, the number of filament and lamellar chloride cells did not change, but filament chloride cells were more abundant than lamellar chloride cells. In contrast, filament chloride cells had increased in size after 72 h and by 168 h after transfer from 30‰ were 1.4-fold larger than the initial size. In 15‰, the number of filament chloride cells and the size of both filament and lamellar chloride cells had decreased after 72 h. Our results demonstrate that snapper can osmoregulate in a wide range of salinity and provide indirect evidence that both filament and lamellar chloride cells are responsible for excretion of excess salt from snapper in hyperosmotic environments. The ability for snapper to adapt rapidly and maintain homeostasis in a wide range of salinities supports the fact that snapper are a suitable species for land-based aquaculture in ponds, where rapid fluctuation in salinity can occur.

Seasonal cycle in energy content of gonad, perivisceral fat, liver, and muscle was used to estimate the energy cost of spawning of female red porgy (Pagrus pagrus) from Buenos Aires coasts, Argentina. Spawning was observed primarily between November and January, although a low-intensity spawning was also observed at the beginning of this period. The energy required for gonad development of female red porgy (the difference between the maximum and minimum energy content of ovaries along the year) was 2,652 J g−1 dry weight or 558 kJ. Female red porgy expend 22.8% of their total body energy (3,481 kJ) during the spawning period. Of this energy, relative contributions from different sources were as follows: ovaries 62.5% (496 kJ), perivisceral fat 17.8% (142 kJ), liver 10.3% (82 kJ), and muscles 9.4% (75 kJ). Female spawners lost about 7.2% (119 g) of their total body weight (1,654 g) in the spawning period. From the 7.2% of the total weight lost, female gonad represented a relative reduction of 73.8% (87.6 g), the perivisceral fat declined by 5.7% (6.8 g), the liver declined by 10.6% (12.5 g), and muscle tissue exhibited a 10% loss in total weight (11.9 g). Reproductive effort represented 7.6% of food energy, while resting metabolism accounted for almost 38% of food energy. Despite the fact that red porgy females feed throughout the entire spawning period, it is shown that between pre-spawning (September, water temperature 15°C) and mid-spawning (December, water temperature 19°C) they lost 45 and 38% of their muscle and liver lipids, respectively, and 89% of the perivisceral fat associated with the gut and body cavity. Red porgy used both their energy reserves and food energy during ovarian maturation. This asynchronous species have a strategy of a lower energy allocation and a higher dependence of food during the spawning time (late-spring and summer) for successful reproduction.

Minimum size limits may be ineffective for reef fishes because they often sustain barotrauma when caught from deep (>20 m) waters. A study was undertaken in conjunction with hook-and-line commercial fishermen to calculate discard percentages and evaluate potential release mortality of eight economically important species: black sea bass, Centropristis striata (Linnaeus), red grouper, Epinephelus morio (Valenciennes), snowy grouper, Epinephelus niveatus (Valenciennes), gag, Mycteroperca microlepis (Goode and Bean), scamp, Mycte- roperca phenax (Jordan and Swain), vermilion snapper, Rhomboplites aurorubens (Cuvier), white grunt, Haemulon plumieri (Lacepede) and red porgy, Pagrus pagrus (Linnaeus). Fishing with baited hook and line occurred in 2004 and 2005 in Onslow Bay, NC, in waters 19-150 m deep. Sub-legal discard rates were 15% for vermilion snapper, 25% for red porgy, 7% for red grouper, 33% for gag, 35% for scamp and 12% for black sea bass. Although mortality based on post-release behaviour was relatively low, higher mortalities estimated from models incor- porating hooking location and depth of capture suggest that minimum size limits may not provide the population benefits intended by management in the North Carolina reef fishery.

The red porgy, Pagrus pagrus (L.), is a protogynous sparid associated with reefs and hard bottom habitat throughout the warm-temperate Atlantic Ocean. In this study, the degree of geographic population differentiation in Atlantic populations was examined with microsatellite and mitochondrial DNA markers (mtDNA). Six microsatellite loci were amplified and scored in 690 individuals from the eastern North Atlantic (Crete, Madeira, and Azores), western North Atlantic (North Carolina to Florida, and the eastern Gulf of Mexico), and Brazil. At two loci, fixed allelic differences were found among the three major geographic areas, while frequency differences were observed at three other loci. The DNA of 371 individuals was amplified at the mtDNA control region, and 526 bp were sequenced. Tamura–Nei’s D was used as a measure of nucleotide diversity and divergence: diversity averaged 0.011 within samples, while the corrected divergence averaged 0 between samples within the same area and 0.061 between samples from different areas. Transversion haplotype minimum spanning networks, nucleotide divergence, and FST values all show that the western Atlantic samples were more closely related to each other than any was to samples from the eastern North Atlantic. Within the western North Atlantic, no significant population differentiation was observed, and within the eastern North Atlantic, only the Azores sample showed detectable differences from Crete and Madeira. These data indicate general homogeneity within large areas, and deep divisions between these areas.

Across three areas, open-circuit scuba (OC) and rebreather (RB) surveys produced similar results for the density and size distribution of fish species inside and outside marine reserves. At Tonga Island, more Notolabrus celidotus were counted with OC than with RB, independently of reserve status [log-scale response ratio of OC/RB (RR) = 0.7]. At Long Island, differences in abundance of Parapercis colias between sampling methods were small at reserve sites (RR = −0.1), but more were counted with scuba than with RBs at fished sites (RR = 0.5). RRs for Pagrus auratus were −1.0 in fished areas and 0.3 in the reserve at Leigh. We also sampled each site using a baited video system (BUV) to establish whether diver-transects sampled the full size range of target species. Most fish in BUV views were Parapercis colias at Long Island (97%), and Pagrus auratus at Leigh (77%). Size structures of Parapercis colias were similar among all three sampling methods within reserve and fished areas at Long Island (max. chi-squared distance = 0.11). BUV samples for Pagrus auratus at Leigh did not detect a prominent juvenile size class observed by divers, but size-frequency distributions of OC, RB, and BUV corresponded at sizes beyond 15 cm TL (max. chi-squared distance = 0.08). To investigate the effects of diver sound on fish behaviour at Long Island, we also compared fish activity when divers with RBs or scuba were present, when the sound of each breathing apparatus was replayed underwater, when no divers were present and no sound was replayed, and when bait was provided, within the reserve only. The lowest number of fish visits to the focal area (mean of 3.0 per 10 min) for Parapercis colias occurred with RB divers present. Maximum abundances of Parapercis colias in all speaker treatments averaged 4.1 per 10 min, whereas with scuba divers present maximum abundances were 5.7, and with baits the average was 38.0 per 10 min.

The effects of salinity and temperature on performance were determined for Australian snapper, Pagrus auratus first-feeding to pre-metamorphosis larvae held in 100-l recirculation tanks. In the first experiment, performance was assessed after transfer from 35‰ at eight salinity treatments (5‰, 10‰, 15‰, 20‰, 25‰ 30‰, 35‰ and 45‰) in larvae from 3 to 21 days after hatching (dah). Survival of larvae was best within the range of 20–35‰. Final size of larvae was similar within the range of 10–35‰ (6.8 ± 0.1 to 7.1 ± 0.2 mm total length [TL]; 3.0 ± 0.3 to 3.3 ± 0.3 mg wet weight) but larvae were 15% shorter at 45‰. Final swimbladder inflation and feeding onset of larvae was not affected by salinity in the range of 10–45‰. The presence of calculi in the urinary bladder of larvae was correlated positively with increasing salinity but no relationship between urinary calculi and larval survival was observed. In a second experiment, performance was assessed after transfer from 21 °C at seven temperature treatments (15, 18, 21, 24, 27, 30 and 33 °C) in larvae from 3–21 dah. All larvae transferred from 21 °C to 30 °C and 33 °C died after 3 days and from 21 °C to 27 °C died after 9 days. Survival was not significantly different between 15 °C and 24 °C. Larval growth increased as temperature was increased; larvae at 24 °C (4.8 ± 0.2 mg wet weight) were 6-fold heavier than larvae at 15 °C. Swimbladder inflation of larvae grown at 18 °C, 21 °C and 24 °C was high (65.2 ± 18.0% to 86.7 ± 8.8%) and similar but inflation was lower in 15 °C and 27 °C. The incidence of urinary calculi occurred earlier and in a greater number of larvae when temperature was increased. Feeding onset was not affected by temperature. In a third experiment, performance was assessed at combinations of two salinities (20‰ and 35‰) and three temperatures (18 °C, 21 °C, and 24 °C) in larvae from 3 to 24 dah. Survival of snapper larvae was not significantly different between these treatments. Growth was not affected by salinity but larvae increased in size as temperature was increased and there was no interaction of salinity and temperature. The percentage of larvae that commenced feeding and inflated their swimbladders was similar in all treatments. Salinity and temperature influenced the incidence of urinary calculi and there was an interaction between the parameters. Based on our results in terms of larval performance (growth), development and survival, we conclude that the optimal conditions for larval rearing of snapper from first-feeding (3 dah) to pre-metamorphosis (24 dah) are combinations of salinity from 20‰ to 35‰ and a temperature of 24 °C.