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Shelf areas of the seas and oceans characterizing high productivity are the spawning sites of many aquatic organisms. However, they are strong impacted for anthropogenic pollution, including oil contamination, which negatively influence on marine organisms. The effects of mazut and diesel fuel in the concentrations of 0.05, 0.1 and 0.2 ml/l on the activity of antioxidant enzymes which are recognized as biomarkers of the oxidative stress namely superoxide dismutase (SOD), catalase (CAT), peroxidase (PER) and glutathione reductase (GR) in the developing embryos of two marine blennies Parablennius sanguinolentus and Salaria pavo (Perciformes: Blenniidae) on the V - VI developmental stages were studied. The results demonstrated higher mazut toxicity as compared with diesel fuel. In P. sanguinolentus embryos exposed to mazut the activity of key anti-oxidant enzymes SOD and CAT were significantly higher (+413% and +100% as compared with the control, p<0.05), while in the case of diesel fuel the enzymes level varied insignificantly. In the embryos of S. pavo SOD and CAT activities were also increased at mazut incubation (256% and 103% respectively, p<0.05), while the differences between enzymes level in embryos exposed to diesel fuel were lower. In contaminated S. pavo embryos enzyme activities varied less as compared with the embryos of P. sanguinolentus, therefore they are more resistant and adaptive to oil contamination. The possible mechanisms of fish embryos antioxidant system response to oil pollution are discussed. [ABSTRACT FROM AUTHOR]

Summary: The siganid production in the Philippines is continuously declining from 2007 up to present. In Palompon, Leyte, annual yield of siganids, particularly Siganus canaliculatus (Park, 1797) also showed a decreasing trend of total production. This is consistent that this stock is under heavy pressure, and when left unmanaged, this could lead to further overexploitation and the collapse of the stock in the long run. Regardless of this, detailed reproductive biology and potential of this species are very few in the Philippines. Therefore, this study was conducted to provide information on the reproductive biology and breeding cycle of S. canaliculatus in Palompon, Leyte where fishing pressure is high and sound management formulation is necessary. S. canaliculatus is a group‐synchronous, multiple spawners with skewed sex ratio where males predominates over females. Maturity stages based on macroscopic examinations identified four maturity stages (immature, developing, mature and spent) while six maturity stages (immature, developing, mature, spawning, spent and re‐developing) were identified through histological analysis. A single ovo‐testis was identified among the 669 specimens examined. Based on histological sections, the smallest size of mature male was 5.5 cm standard length, and the smallest mature female was 7.1 cm standard length. On the other hand, length at first maturity for mature fish were 8.1 cm standard length for males and 9.7 cm standard length for females. Two defined peaks of gonadosomatic index were identified in both sexes: a major peak from February to May and a minor protracted one from July to December. Mature and older ovaries and testes occurred throughout the year, an indication of your round breeding season of S. canaliculatus in Palompon. Implementing a fishing ban during the major and the minor breeding spawning peaks would allow the mature and older individuals to contribute first to the population; allowing the continuity of the stock. [ABSTRACT FROM AUTHOR]

Indonesia is an archipelago that has a wealth of marine fish resources, and the country with the second-longest coastline in the world. The improvement witnessed in the economy of Indonesia in recent years, is as a result of the growth experienced in various sectors, among which is the fisheries and marine. To overcome this problem, a portable conveyor system of moving equipment for fishermen’s catches was designed. It can be placed at the dock or port where the fishermen are anchored and unloading the fishermen’s catches from the sea. It designed to have the ability to move up and down in the moving frame, making this conveyor system can be used both in high tides and low tides of seawater level conditions. The advantage of this portable conveyor system is could be done continuously with a little human power. Other than that, from the results of the calculations, known that with increasing motor rotation, the required traveling time will only become shorter. The resulting conveyor capacity shows an increase. Also, it can use drive motors that are available on the market with a power capacity of 0.37 kW. Therefore, the process of this portable conveyor system can be more efficient.

Blue Growth is a relatively new term that is meant to realize economic growth based on the exploitation of marine resources, while at the same time preventing their degradation, overuse, and pollution. This article discusses the relevance and usefulness of this new concept for the development of capture fisheries, a sector where growth largely seems impossible without ecological devastation. An analytical distinction between intensive and extensive growth is used to argue that certain development trajectories of capture fisheries might qualify as Blue Growth. Such trajectories of growth are illustrated with the development of the Swedish bleak roe trawl fishery in the Bothnian Bay and Norwegian whitefish fishery in the Barents Sea. Comparison of the cases highlights aspects that Blue Growth advocates might want to include if they choose to consider capture fisheries as a relevant economic activity. These aspects include: a) adding value through certification; b) technological development to make more efficient use of resources used up in the fishing operation, and to upgrade their fish as commodity; and c) specialization. [ABSTRACT FROM AUTHOR]

Feeding copepods during early larval culture stages of marine fish has proven to be advantageous for growth and survival of marine finfish larvae. However, commercial availability of most copepods is limited; thus, there is an impetus to evaluate promising copepod species to meet the diverse dietary demands of various marine fish. The marine cyclopoid copepod, Oithona colcarva, was isolated out of zooplankton samples taken from waters within Tampa Bay, Florida. Once isolated, trials were conducted to determine the appropriate culture parameters for producing nauplii to feed marine fish larvae. The effects of temperature (22°C, 26°C and 30°C), salinity (15, 20, 25, 30 and 35 g L−1), stocking density (0.5, 1.0, 2.0, 4.0 and 8.0 individuals mL−1) and diet (Nanno 3600 microalgae paste, Colurella adriatica, Rhodomonas lens, Tisochrysis lutea, Chaetoceros gracilis and/or Tetraselmis chuii) on nauplii production during a single life cycle of reproducing individuals were examined. Results of those trials indicated that a culture temperature of 30°C and a salinity of 30 g L−1 were advantageous for maximum nauplii production. Furthermore, a diet containing a 1:1:1 mixture of T. lutea, C. gracilis and T. chuii and a stocking density of at least 8 individuals mL−1 were identified as beneficial. The results of these trials, the potential for large-scale culture and observations on the performance of marine fish larvae fed Oithona colcarva nauplii are discussed. [ABSTRACT FROM AUTHOR]

Marine fish populations exist in a complex environment, with oceanographic and fisheries factors affecting their dynamics. It has been shown that life history characteristics of marine fish vary in space and time. We examined spatial variability in growth of eight groundfish species in the Northeast Pacific Ocean to identify shared spatial patterns and hypothesize about common mechanisms behind them. Growth parameters were estimated in different areas over the latitudinal range of the species, and several hypotheses were tested as to how these parameters vary along the US west coast. Clear differences in spatial growth variability emerged among the species examined. Shelf species exhibit the highest growth rate between Cape Blanco and Cape Mendocino, which may, in part, be attributed to area-specific upwelling patterns in the California Current ecosystem, when nutrient-rich deep water is brought to the surface south of Cape Blanco and is uniquely distributed throughout this area, providing favourable conditions for primary productivity. Slope species showed a cline in asymptotic size (L∞), with L∞ increasing from south to north. This cline, previously attributed to fishery removals, also fits a specific case of the widely described Bergmann's rule, and we explore specific potential ecological mechanisms behind this relationship. [ABSTRACT FROM AUTHOR]

The effects of 2 currently used commercial pesticide formulations on Pacific sockeye salmon ( Oncorhynchus nerka), from fertilization to emergence, were evaluated in a gravel-bed flume incubator that simulated a natural streambed. Embryos were exposed to atrazine at 25 µg/L (low atrazine) or atrazine at 250 µg/L (high atrazine) active ingredient (a.i.), and chlorothalonil at 0.5 µg/L (low chlorothalonil) or chlorothalonil at 5 µg/L a.i. (high chlorothalonil) and examined for effects on developmental success and timing, as well as physical and biochemical growth parameters. Survival to hatch was reduced in the high chlorothalonil group (55% compared with 83% in controls), accompanied by a 24% increase in finfold deformity incidence. Reduced alevin condition factor (2.9-5.4%) at emergence and elevated triglyceride levels were seen in chlorothalonil-exposed fish. Atrazine exposure caused premature hatch (average high atrazine time to 50% hatch [H50] = 100 d postfertilization [dpf]), and chlorothalonil exposure caused delayed hatch (high chlorothalonil H50 = 108 dpf; controls H50 = 102 dpf). All treatments caused premature emergence (average time to 50% emergence [E50]: control E50 = 181 dpf, low chlorothalonil E50 = 175 dpf, high chlorothalonil E50 = 174 dpf, high atrazine E50 = 175 dpf, low atrazine E50 = 174 dpf), highlighting the importance of using a gravel-bed incubator to examine this subtle, but critical endpoint. These alterations indicate that atrazine and chlorothalonil could affect survival of early life stages of sockeye salmon in the wild. Environ Toxicol Chem 2017;36:1354-1364. © 2017 SETAC [ABSTRACT FROM AUTHOR]

We estimated the current level of knowledge concerning several biological characteristics of the Mediterranean marine fishes by carrying out a gap analysis based on information extracted from the literature, aiming to identify research trends and future needs in the field of Mediterranean fish biology that can be used in stock assessments, ecosystem modeling and fisheries management. Based on the datasets that emerged from the literature review, there is no information on any biological characteristic for 43% (n = 310) of the Mediterranean fish species, whereas for an additional 15% (n = 109) of them there is information about just one characteristic. The gap between current and desired knowledge (defined here as having information on most biological characteristics for at least half of the Mediterranean marine fishes) is smaller in length-weight relationships, which have been studied for 43% of the species, followed by spawning (39%), diet (29%), growth (25%), maturity (24%), lifespan (19%) and fecundity (17%). The gap is larger in natural mortality for which information is very scarce (8%). European hake (Merluccius merluccius), red mullet (Mullus barbatus), annular seabream (Diplodus annularis), common pandora (Pagellus erythrinus), European anchovy (Engraulis encrasicolus), European pilchard (Sardina pilchardus) and bogue (Boops boops) were the most studied species, while sharks and rays were among the least studied ones. Only 25 species were fully studied, i.e. there was available information on all their biological characteristics. The knowledge gaps per characteristic varied among the western, central and eastern Mediterranean subregions. The number of available records per species was positively related to total landings, while no relationship emerged with its maximum reported length, trophic level and commercial value. Future research priorities that should be focused on less studied species (e.g. sharks and rays) and mortality/fecundity instead of length-weight relationships, as well as the economy of scientific sampling (using the entire catch to acquire data on as many biological characteristics as possible) are discussed. [ABSTRACT FROM AUTHOR]

This study examines the relationships between first year growth of juvenile Prince William Sound herring, temperature and their food. We present time series of herring first year growth, determined from scale measurements as a proxy for herring length, water temperature and indices of multiple trophic levels of plankton obtained from Continuous Plankton Recorder (CPR) sampling on the adjacent Gulf of Alaska shelf. We show that there was a significant correlation between herring growth and water temperature, when the three warmest years were excluded (the mean July and August temperatures were greater than 12.5°C in 1989, 2004 and 2005). There were also strong, significant relationships between the abundance of appropriately sized (for first-feeding herring) planktonic prey groups and herring growth. First year herring growth was greater in years with higher abundances of diatoms, microzooplankton and small mesozooplankton but not related to variability in abundance of larger mesozooplankton (such as euphausiids and large copepods). Furthermore, the strong interannual relationship between diatoms and herring growth held true even in the warmest years where the relationship between temperature and growth broke down. We also found seasonal timing and abundance changes in the plankton in warm years that would make the prey more abundant during the summer months immediately after metamorphosis of the herring larvae. We thus conclude that young-of-the-year herring may grow better in warm years because the timing of key prey is a better match for their first feeding. [ABSTRACT FROM AUTHOR]

The fisheries sector is crucial to the Bangladeshi economy and wellbeing, accounting for 4.4% of national gross domestic product and 22.8% of agriculture sector production, and supplying ca. 60% of the national animal protein intake. Fish is vital to the 16 million Bangladeshis living near the coast, a number that has doubled since the 1980s. Here, we develop and apply tools to project the long-term productive capacity of Bangladesh marine fisheries under climate and fisheries management scenarios, based on downscaling a global climate model, using associated river flow and nutrient loading estimates, projecting high-resolution changes in physical and biochemical ocean properties, and eventually projecting fish production and catch potential under different fishing mortality targets. We place particular interest on Hilsa shad (Tenualosa ilisha), which accounts for ca. 11% of total catches, and Bombay duck (Harpadon nehereus), a low price fish that is the second highest catch in Bangladesh and is highly consumed by low-income communities. It is concluded that the impacts of climate change, under greenhouse emissions scenario A1B, are likely to reduce the potential fish production in the Bangladesh exclusive economic zone by ,10%. However, these impacts are larger for the two target species. Under sustainable management practices, we expect Hilsa shad catches to show a minor decline in potential catch by 2030 but a significant (25%) decline by 2060. However, if overexploitation is allowed, catches are projected to fall much further, by almost 95% by 2060, compared with the Business as Usual scenario for the start of the 21st century. For Bombay duck, potential catches by 2060 under sustainable scenarios will produce a decline of ,20% compared with current catches. The results demonstrate that management can mitigate or exacerbate the effects of climate change on ecosystem productivity. [ABSTRACT FROM AUTHOR]

An increasing number of studies have examined the effects of elevated carbon dioxide (CO2) and ocean acidification on marine fish, yet little is known about the effects on large pelagic fish. We tested the effects of elevated CO2 on the early life history development and behaviour of yellowtail kingfish, Seriola lalandi. Eggs and larvae were reared in current day control (450 µatm) and two elevated CO2 treatments for a total of 6 d, from 12 h post-fertilization until 3 d post-hatching (dph). Elevated CO2 treatments matched projections for the open ocean by the year 2100 under RCP 8.5 (880 µatm CO2) and a higher level (1700 µatm CO2) relevant to upwelling zones where pelagic fish often spawn. There was no effect of elevated CO2 on survival to hatching or 3 dph. Oil globule diameter decreased with an increasing CO2 level, indicating potential effects of elevated CO2 on energy utilization of newly hatched larvae, but other morphometric traits did not differ among treatments. Contrary to expectations, there were no effects of elevated CO2 on larval behaviour. Activity level, startle response, and phototaxis did not differ among treatments. Our results contrast with findings for reef fish, where a wide range of sensory and behavioural effects have been reported. We hypothesize that the absence of behavioural effects in 3 dph yellowtail kingfish is due to the early developmental state of newly hatched pelagic fish. Behavioural effects of high CO2 may not occur until larvae commence branchial acid-base regulation when the gills develop; however, further studies are required to test this hypothesis. Our results suggest that the early stages of kingfish development are tolerant to rising CO2 levels in the ocean. [ABSTRACT FROM AUTHOR]

Increased oceanic uptake of atmospheric carbon dioxide (CO2) is a threat to marine organisms and ecosystems. Among the most dramatic consequences predicted to date are behavioural impairments in marine fish which appear to be caused by the interference of elevated CO2 with a key neurotransmitter receptor in the brain. In this study, we tested the effects of elevated CO2 on the foraging and shelter-seeking behaviours of the reef-dwelling epaulette shark, Hemiscyllium ocellatum. Juvenile sharks were exposed for 30 d to control CO2 (400 µatm) and two elevated CO2 treatments (615 and 910 µatm), consistent with medium- and high-end projections for ocean pCO2 by 2100. Contrary to the effects observed in teleosts and in some other sharks, behaviour of the epaulette shark was unaffected by elevated CO2. A potential explanation is the remarkable adaptation of H. ocellatum to low environmental oxygen conditions (hypoxia) and diel fluctuations in CO2 encountered in their shallow reef habitat. This ability translates into behavioural tolerance of near-future ocean acidification, suggesting that behavioural tolerance and subsequent adaptation to projected future CO2 levels might be possible in some other fish, if adaptation can keep pace with the rate of rising CO2 levels. [ABSTRACT FROM AUTHOR]

Increased oceanic uptake of atmospheric carbon dioxide (CO2) is a threat to marine organisms and ecosystems. Among the most dramatic consequences predicted to date are behavioural impairments in marine fish which appear to be caused by the interference of elevated CO2 with a key neurotransmitter receptor in the brain. In this study, we tested the effects of elevated CO2 on the foraging and shelter-seeking behaviours of the reef-dwelling epaulette shark, Hemiscyllium ocellatum. Juvenile sharks were exposed for 30 d to control CO2 (400 µatm) and two elevated CO2 treatments (615 and 910 µatm), consistent with medium- and high-end projections for ocean pCO2 by 2100. Contrary to the effects observed in teleosts and in some other sharks, behaviour of the epaulette shark was unaffected by elevated CO2. A potential explanation is the remarkable adaptation of H. ocellatum to low environmental oxygen conditions (hypoxia) and diel fluctuations in CO2 encountered in their shallow reef habitat. This ability translates into behavioural tolerance of near-future ocean acidification, suggesting that behavioural tolerance and subsequent adaptation to projected future CO2 levels might be possible in some other fish, if adaptation can keep pace with the rate of rising CO2 levels. [ABSTRACT FROM AUTHOR]

This study investigated and compared asymmetry in sagittal otolith shape and length between left and right inner ears in four roundfish and four flatfish species of commercial interest. For each species, the effects of ontogenetic changes (individual age and total body length), sexual dimorphism (individual sex) and the otolith's location on the right or left side of the head, on the shape and length of paired otoliths (between 143 and 702 pairs according to species) were evaluated. Ontogenetic changes in otolith shape and length were observed for all species. Sexual dimorphism, either in otolith shape and length or in their ontogenetic changes, was detected for half of the species, be they round or flat. Significant directional asymmetry in otolith shape and length was detected in one roundfish species each, but its inconsistency across species and its small average amplitude (6·17% for shape and 1·99% for length) suggested that it has barely any biological relevance. Significant directional asymmetry in otolith shape and length was found for all flatfish species except otolith length for one species. Its average amplitude varied between 2·06 and 17·50% for shape and between 0·00 and 11·83% for length and increased significantly throughout ontogeny for two species, one dextral and one sinistral. The longer (length) and rounder otolith (shape) appeared to be always on the blind side whatever the species. These results suggest differential biomineralization between the blind and ocular inner ears in flatfish species that could result from perturbations of the proximal-distal gradient of otolith precursors in the endolymph and the otolith position relative to the geometry of the saccular epithelium due to body morphology asymmetry and lateralized behaviour. The fact that asymmetry never exceeded 18% even at the individual level suggests an evolutionary canalization of otolith shape symmetry to avoid negative effects on fish hearing and balance. Technically, asymmetry should be accounted for in future studies based on otolith shape. [ABSTRACT FROM AUTHOR]

Insulin-like growth factor (Igf) is the key regulator for development, growth, and reproduction. In most vertebrate species, the Igf family has two forms: Igf1 and Igf2. A novel form of Igf, termed Igf3, was recently discovered in fish. In the present study, we isolated igf3 from the orange-spotted grouper ( Epinephelus coioides ). The orange-spotted grouper igf3 consisted of a full-length cDNA of 1014 nucleotides with an open reading frame (ORF) of 597 bp, encoding for proteins of 199 amino acid residues in length. Tissue distribution analysis showed that igf1 widely expressed with the highest expression in the pituitary and liver. igf2 was expressed highly in all the tissues except the olfactory bulb, while igf3 showed the highest expression in the ovary, and moderate expression in brain areas. The expression profiles of three igf genes during the ovarian development and growth hormone (Gh) and human chorionic gonadotropin (hCG) treatment were also investigated. Three igf genes exhibited different expression patterns during the ovarian development, and showed different responses to the Gh and hCG treatments, appearing to play distinct roles in ovarian development. The present study provides further evidence for the existence of an intraovarian Igf system in orange-spotted grouper. [ABSTRACT FROM AUTHOR]

Recruitment often varies substantially in fish populations, and residual variability may have serial autocorrelation due to environmental effects even after accounting for a stock-recruitment relationship. However, the likely magnitude of variability and autocorrelation in recruitment has yet to be formally estimated. We therefore developed a hierarchical model for recruitment variability and autocorrelation and applied it to data for 154 fish populations. Results were similar when using either the Ricker or Beverton-Holt stock-recruitment model, and showed that autocorrelated recruitment has a marginal standard deviation of 0.74 (SD = 0.35) and a mean autocorrelation of 0.43 (SD = 0.28) when predicting for an unobserved taxonomic order. Estimates differed somewhat among taxonomic orders and stocks, and also supported a hypothesized positive relationship between age at maturity and autocorrelation in recruitment. Our results can be used as a Bayesian prior for recruitment variability in models for data-poor stocks and to distinguish recruitment from other process errors in models for data-rich stocks. Estimates can also be used in the design of future simulation models and management strategy evaluations and in theoretical research regarding life history variation. [ABSTRACT FROM AUTHOR]

We explain in an intuitive and detailed way a predator-prey model that generates cyclic dominance in Fraser River sockeye salmon. In contrast with usual predator-prey models, this model includes four distinct prey lines and thus a combination of continuous and discrete dynamics, reflecting the particular freshwater and marine life cycle features of sockeye salmon ( Oncorhynchus nerka) populations. The predator-prey interaction causing the oscillations takes place in the rearing lakes, rather than in the ocean. The values of most parameters of this model can be estimated from empirical data that are available for the large salmon-rearing lakes in the Fraser River basin. The mechanism that produces the oscillations in this model is compared with other mechanisms that can generate population oscillations, and we argue that predator-prey dynamics is the most likely mechanism to produce the observed patterns. We explain why the period of the oscillation is exactly 4 years, and we explore how the dynamical pattern is affected by changes in external conditions or by management decisions. [ABSTRACT FROM AUTHOR]

Larval Sea LampreysPetromyzon marinuslive burrowed in stream bottoms and then metamorphose into their parasitic stage. Among larvae that metamorphose in a given year (i.e., parasitic cohort), autumn out-migrants (October–December) to the Laurentian Great Lakes can feed on fish for up to 6 months longer than spring out-migrants (March–May), which overwinter in streams without feeding. We evaluated whether the season of out-migration affected growth or survival of newly metamorphosed Sea Lampreys in Lake Huron. Newly metamorphosed individuals (n= 2,718) from three parasitic cohorts were netted during their out-migration from Black Mallard Creek, Michigan, to Lake Huron during autumn 1997 through spring 2000; each out-migrant was injected with a sequentially numbered coded wire tag and was released back into the creek. After up to 18 months of feeding in the Great Lakes, 224 (8.2%) Sea Lampreys were recaptured (in 1999–2001) as upstream-migrating adults in tributaries to Lakes Huron and Michigan. Recovery rates of autumn and spring out-migrants as adults were 9.4% and 7.8%, respectively, and these rates did not significantly differ. Overwinter feeding (i.e., as parasites) by autumn out-migrants did not produce adult mean sizes greater than those of spring out-migrants. Because we detected no growth or survival differences between autumn and spring out-migrants, the capture of newly metamorphosed Sea Lampreys at any point during their out-migration should provide equal reductions in damage to Great Lakes fisheries. The absence of a difference in growth or survival between autumn and spring out-migrants is an aspect of Sea Lamprey life history that yields resiliency to this invasive parasite and complicates efforts for its control in the Great Lakes. Received August 2, 2013; accepted October 26, 2013 [ABSTRACT FROM AUTHOR]

Abstract: Iodine is an important micronutrient for the marine fish metamorphosis and rotifers contain relatively low amounts of iodine compared to copepods, the main natural prey for marine fish larvae. In previous studies, rotifers were enriched with iodine from NaI. However, this source of iodine is poorly retained in rotifers during storage. In the present study rotifers were enriched (3h) with graded levels of thymol iodide (TI), 3-5-diiodosalicylic acid (DISA), chelated iodine (CI), kelp and sodium iodide (NaI) mixed with a commercial enrichment diet (Ori-green®). Thereafter, iodine retention in rotifers enriched with selected iodine sources and concentration and stored (0, 1, 2, 5, 10 and 18h) at high and low temperatures was studied (room temperatures at 24 and 7°C, respectively). Linear regression showed a positive relationship between dietary and rotifer iodine concentration for all iodine sources. Results from the first trial showed that 0.36–2.03% replacement of the enrichment diet with TI, gave copepod iodine levels. Maximum iodine level (446.67mgkg−1 DW) was observed in the rotifers fed with a diet containing 9.7gkg−1 rotifer DW, added iodine from TI. 118mgkg−1 DW iodine was observed in rotifers fed with diet containing 9.7gkg−1 rotifer DW, added iodine from DISA. Rotifers enriched with kelp, gained maximum up to 196mgkg−1 DW iodine in this study. Chelated iodine was a poor source of iodine for rotifer enrichment. Even with 100% replacement of the enrichment diet with CI, rotifers were not able to reach the lower copepod iodine level (50mgkg−1 DW). 0.3gl−1 NaI gave 370mgkg−1 DW iodine in rotifers. Trial 1 indicated that with TI, DISA and NaI, rotifers can be enriched to copepod level with minimal replacement of the enrichment diet. In trial 2, temperature did not affect the rotifer iodine retention. In the first h of storage, rotifer enriched with TI lost 34–62% iodine and rotifers enriched with DISA lost 55–66% iodine while NaI enriched rotifers lost 78–85% iodine. After 18h storage 79–97% loss was observed in rotifers enriched with NaI and 40–56% loss was observed in rotifers enriched with TI. Loss of the other compounds was intermediate. In conclusion, thymol iodide seems to be a good source of iodine for enrichment of rotifers as only <2.5% replacement of the enrichment diet gives copepod iodine levels and after enrichment followed by storage at high or low temperature for 18h, rotifers are able to retain relatively high amounts of iodine in their body. [Copyright &y& Elsevier]

Abstract: We studied the feasibility of weaning common sole (Solea solea L.) larvae at 13days post hatching (dph) using commercial microdiets (MDs) while reducing live-feed utilization. Four dph larvae were fed two kinds of experimental weaning feeding regimens (FRs): control FR-C (AgloNorse, Ewos) where larvae were weaned onto MD at 27 dph; whilst the other FRs provided live feed until 13 dph, employing AgloNorse, Ewos (FR-A), Gemma, Skretting (FR-G) and O.range Large, INVE (FR-O). The trial lasted 29days. No statistical differences among groups were observed in survival rates at the end of the trial. FR-A, FR-G and FR-O showed significantly lower weight and length increase when compared to control, whereas metamorphosis development was not influenced. Fatty acids larvae profile was significantly influenced by FR. The total number of Vibrio spp. was significantly higher in FR-C tanks at 21 dph. Salinity stress test values were not influenced by treatments. In conclusion, a very early weaning at 13 dph using commercial MDs in common sole larvae affects growth performance but not survival rate and metamorphosis development. A shorter live feed utilization improved tank hygiene. [Copyright &y& Elsevier]

Recent advances in crayfish feeding have enabled the development of size grading studies from the start of first-feeding. A 180-day experiment aimed at intensive rearing of Pacifastacus leniusculus was carried out under controlled conditions, evaluating the effects of size grading at two different periods from the onset of exogenous feeding. Stage 2 juveniles were stocked in fibreglass tanks at a density of 100 m2, and fed a dry diet for salmonids combined with restricted amounts of Artemia cysts. Five groups were tested: no grading, grading at 60 days (large and small size) and grading at 100 days (large and small size). After 6 months, no significant differences were found in the survival among groups (mean: 73.06%). The highest final growth (pooled results from upper and lower classes: 17.39 mm carapace length, 1.43 g weight) was achieved by the crayfish sorted at 60 days, showing significant differences from the ungraded group. Smaller crayfish graded at 60 days grew significantly faster than smaller crayfish graded at 100 days. The food conversion ratio was lower in the graded groups (mean: 2.64), showing significant differences from the ungraded group (3.23). This study shows that size grading allows a better performance and an improved feeding efficiency. [ABSTRACT FROM AUTHOR]

Together with docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), arachidonic acid (ARA) is being considered to be an essential fatty acid in marine fish larval diets. The objective of the present study was to determine the importance of dietary ARA levels for larval European sea bass performance, when EPA and DHA are also present in the diet. Eighteen-day-old larvae were fed, for 14 days, gelatine-based microdiets containing the following ARA levels: 0.3%, 0.6% or 1.2%. Elevation of dietary ARA up to 1.2% showed a positive correlation with larval survival and a significant improvement in the specific growth rates, body weight and total length. Arachidonic acid was efficiently incorporated into larval lipids, even at a higher proportion than that in the diets. Increased accumulation of ARA did not affect the incorporation of DHA or EPA from the diet into larval total lipids. A significant positive correlation was found between dietary ARA levels and survival after handling stress, indicating the importance of this fatty acid in sea bass larvae response to acute stressors. The results show the importance of ARA for sea bass larvae, but higher dietary levels should be tested to determine whether there is a negative effect of ARA in sea bass as reported for other species. [ABSTRACT FROM AUTHOR]

The Convention on Biological Diversity (CBD) established a target in 2002 to reduce the rate of biodiversity loss by 2010. Using a newly constructed global database for 207 populations (108 species), we examine whether the 2010 target has been met for marine fishes, while accounting for population biomass relative to maximum sustainable yield, BMSY. Although rate of decline has eased for 59% of populations declining before 1992 (a pattern consistent with a literal interpretation of the target), the percentage of populations below BMSY has remained unchanged and the rate of decline has increased among several top predators, many of which are below 0.5BMSY. Combining population trends, a global multispecies index indicates that marine fishes declined 38% between 1970 and 2007. The index has been below BMSY since the mid-1980s and stable since the early 1990s. With the exception of High Seas pelagic fishes and demersal species in the Northeast Pacific and Australia – New Zealand, the multispecies indices are currently below BMSY in many regions. We conclude that the 2010 CBD target represents a weak standard for recovering marine fish biodiversity and that meaningful progress will require population-specific recovery targets and associated time lines for achieving those targets. [ABSTRACT FROM AUTHOR]

Predation is the largest source of mortality for marine fish and may be an important process in regulating population size. Recent population models have attempted to quantify predation separately from other sources of natural mortality. Building upon such work, a multispecies age-structured assessment model (MSASA) for the Gulf of Alaska was developed, which included arrowtooth flounder (Atheresthes stomias), Pacific cod (Gadus macrocephalus), and walleye pollock (Theragra chalcogramma). Predation mortality was a flexible function of predator and prey abundances that was fitted to stomach-content data. A proof of concept illustration is presented here, assessing model outputs against a set of single-species models. The MSASA model was able to successfully estimate predation between species and integrate it into total mortality. Significant predation occurred on younger pollock and flounder. Results indicate a significant change in predation over time on pollock as a function of increased arrowtooth flounder abundance. Estimating mortality and other parameters for three species simultaneously is complex, and the advantage of greater biological realism of MSASA comes at the expense of greater uncertainty in parameter estimation. La prédation représente la plus importante source de mortalité pour les poissons marins et peut être un mécanisme majeur du contrôle de la taille des populations. Des modèles démographiques récents ont essayé de mesurer la prédation séparément des autres sources de mortalité naturelle. Nous basant sur ces travaux, nous avons mis au point un modèle d’évaluation plurispécifique structuré d’après l’âge (« MSASA ») pour le golfe de l’Alaska qui inclut la plie à grande bouche (Atheresthes stomias), la morue du Pacifique (Gadus macrocephalus) et la goberge de l’Alaska (Theragra chalcogramma). La mortalité due à la prédation est une fonction flexible des abondances de prédateurs et de proies ajustée aux données des contenus stomacaux. Nous faisons ici une démonstration de faisabilité en évaluant les données de sortie du modèle par comparaison à celles d’une série de modèles monospécifiques. Le modèle MSASA réussit à estimer la prédation des différentes espèces et à l’intégrer dans la mortalité totale. Il existe une prédation significative des goberges et plies plus jeunes. Les données indiquent un changement significatif de la prédation des goberges dans le temps en fonction de l’accroissement de l’abondance des plies à grande bouche. L’estimation simultanée de la mortalité et des autres variables chez trois espèces est complexe et l’avantage d’un plus grand réalisme biologique apporté par MSASA se fait au coût d’une incertitude accrue dans l’estimation des variables. [ABSTRACT FROM AUTHOR]

The article discusses the research on two large pre-transitional larval tonguefishes found in near surface waters which overlie oceanic waters off the Galapagos Islands. It states that the tonguefishes, which include Symphurus varius Garman and Symphurus melanurus Clark, were described and compared with larval stages and adults of eastern Pacific species of Symphurus. It says that the large size and oceanic presence of Symphunus melanurus suggests a case of delayed metamorphosis for the species.

Estimated length-weight relationships are presented for 11 marine fish species representing six families, found above the continental shelf and in the pelagial of the Okhotsk Sea. A total of 13,841 specimens were caught by trawls that were equipped with a 1.0 by 1.2 cm mesh webbing inset. The period between 1974 and 2015 comprised mostly spring and autumn months. All length-weight relationships were highly significant ( r2 ≥ .95) on a log scale. None of the species had previous length-weight estimates, and two species had no previous length-length estimates in the FishBase. [ABSTRACT FROM AUTHOR]

The article reports presence of the fish Champsodon vorax in the Aegean Sea. Topics discussed include collection of specimen of C. vorax from the sea, morphological analysis revealing meristic counts on all fins, body color found to be dark brown with blotches on dorsal fin, increased colonization rate of Champsodon in the Mediterranean sea, water circulation pattern and ambient temperature of sea being responsible for increased growth of the fish.

The East China Sea is China's most productive fishing area. Maintaining harvest resulted in two notable sea ranching and restocking programs: the southward translocation of prawn (Penaeus orientalis) to establish a new fishery in Xiangshan Bay, and the release of large yellow croaker (Pseudosciaena crocea) to rebuild depleted populations. Penaeus orientalis were reared and released into Xiangshan Bay from 1986 to 1992. The new habitat supported all life stages, and stocked prawns provided a local put-and-take fishery. Although P. orientalis reproduced naturally, no lasting population was established because of the limited size of the releases and intense fishing pressure. From 2001 to 2006, 2-6 million juvenile P. crocea were released annually in Zhejiang Province, showing that it is feasible to release juvenile P. crocea and that they survive, feed, grow, spawn, and migrate, and are beginning to rebuild the population. Along with extensive fisheries, the East China Sea has thousands of hatcheries and some 1,000,000 aquaculture cages. To expand the industry while avoiding environmental problems associated with near-shore cages, large cages that can withstand storms are being used in deeper, well-flushed waters, resulting in improved product quality. [ABSTRACT FROM AUTHOR]

The Chesapeake Bay has traditionally been one of North America's most productive fishing grounds, supporting the world's largest blue crab fishery. During the last several decades, fishing mortality and environmental degradation led to ∼ 70% drop in the bay's blue crab abundance, 84% decline in its spawning stock, and historically low levels of juvenile recruitment as well as nursery habitats being below carrying capacity. This situation makes the Chesapeake Bay blue crab an appropriate candidate for responsible stock enhancement. A multidisciplinary, multi-institutional program was developed to study the basic biology and life cycle of the blue crab, develop hatchery and nursery technologies for mass production of blue crab juveniles, and assess the potential of using cultured juveniles to enhance blue crab breeding stocks and, in turn, bay-wide abundance and harvests. Basic biology and culture studies enabled closing the life cycle of the blue crab in captivity. Juvenile crabs have been produced year round, with excellent survival. During 2002-2006, over 290,000 cultured crabs were tagged and experimentally released into the bay's nursery habitats. Cultured crabs survived as well as their wild counterparts, increased local populations at release sites by 50-250%, grew quickly to sexual maturity, mated, and migrated from the release sites to spawning grounds, contributing to the breeding stock as soon as 5 to 6 months post-release. Findings reported in this text and other articles in this volume are indicative of the feasibility of our approach of using hatchery juveniles to replenish the blue crab breeding stocks in the Chesapeake Bay. [ABSTRACT FROM AUTHOR]

The article discusses the statistical monitoring of cod fish larvae. Beach-seine monitoring program was used in Norway to determine numbers of hatchery data on yolk-sac larval cod released during spring season. However, no evidence found on the long-tern increase of abundant mature cod found in fjords.

Presents information on three hatcher-scale experiments which were designed to examine both the actions and interactions of cortisol and thyroid hormones in the development of larval marine fish. Information on the materials used in the experiments; Details on the experimental methodology; Detailed information on the experimental results; Discussion on the experiment.

Summary The world’s oceans are home to many fantastic creatures, including about 16,000 species of actinopterygian, or ray-finned, fishes. Notably, 85% of marine fish species come from a single actinopterygian subgroup, the acanthomorph or spiny-rayed fishes. Here, we review eight functional innovations found in marine acanthomorphs that have been instrumental in the adaptive radiation of this group in the marine realm. Jaw protrusion substantially enhances the suction feeding mechanism found in all fish. Fin spines serve as a major deterrent to predators and enhance the locomotor function of fins. Pharyngognathy, a specialization of the second pair of jaws in the pharynx, enhances the ability of fishes to process hard and tough prey. Endothermy allows fishes to function at high levels of physiological performance in cold waters and facilitates frequent movement across strong thermal gradients found in the open ocean. Intramandibular joints enhance feeding for fishes that bite and scrape prey attached to hard surfaces. Antifreeze proteins prevent ice crystal growth in extracellular fluids, allowing fish to function in cold waters that would otherwise freeze them. Air-breathing allowed fishes at the water’s edge to exploit terrestrial habitats. Finally, bioluminescence functions in communication, attracting prey and in hiding from predators, particularly for fishes of the deep ocean. All of these innovations have evolved multiple times in fishes. The frequent occurrence of convergent evolution of these complex functional novelties speaks to the persistence and potency of the selective forces in marine environments that challenge fishes and stimulate innovation. [ABSTRACT FROM AUTHOR]

Summary Sharks, rays, and chimaeras (Class Chondrichthyes; herein ‘sharks’) are the earliest extant jawed vertebrates and exhibit some of the greatest functional diversity of all vertebrates. Ecologically, they influence energy transfer vertically through trophic levels and sometimes trophic cascades via direct consumption and predation risk. Through movements and migrations, they connect horizontally and temporally across habitats and ecosystems, integrating energy flows at large spatial scales and across time. This connectivity flows from ontogenetic growth in size and spatial movements, which in turn underpins their relatively low reproductive rates compared with other exploited ocean fishes. Sharks are also ecologically and demographically diverse and are taken in a wide variety of fisheries for multiple products (e.g. meat, fins, teeth, and gills). Consequently, a range of fisheries management measures are generally preferable to ‘silver bullet’ and ‘one size fits all’ conservation actions. Some species with extremely low annual reproductive output can easily become endangered and hence require strict protections to minimize mortality. Other, more prolific species can withstand fishing over the long term if catches are subject to effective catch limits throughout the species’ range. We identify, based on the IUCN Red List status, 64 endangered species in particular need of new or stricter protections and 514 species in need of improvements to fisheries management. We designate priority countries for such actions, recognizing the widely differing fishing pressures and conservation capacity. We hope that this analysis assists efforts to ensure this group of ecologically important and evolutionarily distinct animals can support both ocean ecosystems and human activities in the future. [ABSTRACT FROM AUTHOR]