Wild Marine Fish Research Articles

Draft Genome Sequence of the Fish Pathogen Mycobacterium pseudoshottsii Strain JCM15466, a Species Closely Related to M.marinum.

Mycobacterium pseudoshottsii is a slowly growing photochromogenic mycobacterium and fish pathogen isolated from wild marine fishes. M. pseudoshottsii closely resembles M. marinum, which is a human and animal pathogen. Here, we report the draft genome sequence of M. pseudoshottsii strain JCM15466, originally isolated from striped bass, Morone saxatilis.

Using mercury isotopes to understand the bioaccumulation of Hg in the subtropical Pearl River Estuary, South China

Coastal and estuarine regions are important areas of mercury pollution. Therefore, it is important to properly characterize the sources and bioaccumulation processes of mercury in these regions. Here, we present mercury stable isotopic compositions in 18 species of wild marine fish collected from the Pearl River Estuary (PRE), south China. Our results showed variations in mass-independent fractionation (Δ199Hg: +0.05 ± 0.10‰ to +0.59 ± 0.30‰) with a Δ199Hg/Δ201Hg of ∼1.26, suggesting that aqueous MeHg underwent photo-degradation prior to incorporation into the food chain. For the results, we discovered small but significant differences of Δ199Hg values among herbivorous, demersal, and carnivorous fish, indicating that different feeding guilds of fish may have incorporated MeHg with various degrees of photo-demethylation. The consistent mercury isotope compositions between fish feeding habitat and mercury sources in the estuary provide potentially important findings on the transformation and bioaccumulation of this toxic metal in subtropical coastal environments.

Marine Fish Farming and the Blue Revolution: Culturing Cod Fisheries

The Blue Revolution promises to transform wild marine fish into docile domesticates, fish hunters into harvesters. As commercially fished marine species continue to face extinction in the wild due to over-fishing, pollution, global climate change and a host of other anthropo-genic assaults, ‘culture’ has emerged as a keyword in the field of marine fisheries management. Like the terrestrial dreams and grandiose visions of their Green comrades a half-century earlier, Blue revolutionaries advocate the application of scientific expertise, industrial technology and transnational capital in their oceanic culturing projects. These culturing projects influence and seek to transform human identity and ways of living as much as the genetic make-up, behaviours and metabolism of the wild fish species that are targeted for domestication.

Immunological and health-state parameters in the Patagonian rockfish Sebastes oculatus. Their relation to chemical stressors and seasonal changes.

We present the results of a field study that evaluates whether exposure to anthropogenic pollution impacts immunological and health-state parameters of wild marine fish during the breeding and non-breeding periods. We assessed aspects of innate immunity (bactericidal capacity, bacterial agglutination, and leukocyte profile) and general health-related parameters (neutrophil to lymphocyte ratio, hematocrit, and condition factor) in the Patagonian rockfish (Sebastes oculatus) sampled from polluted (exposed) and reference (control) sites during winter (i.e., coolest temperatures and active reproductive period) and in summer (i.e., warmest temperatures and non-reproductive period). Results showed lower bactericidal competence, hematocrit, and condition factor in fish from exposed sites independently of season, whereas lymphocytes were higher and monocytes lower at the exposed site only during summer. Moreover, fish sampled during winter displayed lower bactericidal competence, hematocrit, and condition factor than those sampled in summer independently of site, whereas the opposite pattern was found for bacterial agglutination. These results could be explained by life-history theory, which predicts a re-allocation of resources between reproduction and other physiological functions (including immunity) during the most energetically demanding season. The present results show an alteration in immunological and health-state parameters of wild marine fish exposed to anthropogenic pollution independently of season, which could potentially result in higher susceptibility to disease and in turn population decline.

Epidemiological characterization of VNNV in hatchery-reared and wild marine fish on Hainan Island, China, and experimental infection of golden pompano (Trachinotus ovatus) juveniles.

The current epidemiological situation of viral nervous necrosis virus (VNNV) on Hainan Island was investigated. A total of 490 hatchery-reared fish and 652 wild fish were sampled for VNNV detection from March 2013 to May 2014. Positive detection rates of 84.53% (153/181) and 0.97 % (3/309) were obtained in diseased and healthy hatchery-reared samples, respectively, by conventional RT-PCR. However, using more-sensitive nested RT-PCR, the positive detection rates in healthy hatchery-reared fish reached up to 64.08% (198/309), suggesting that asymptomatic VNNV carriers commonly exist among larvae and juveniles breeding on Hainan Island. In wild-fish samples, 2.6% (17/652) and 34.2% (223/652) positive detection rates were observed using RT-PCR and nested RT-PCR, respectively, indicating that wild fish may be a potential reservoir for VNNV. Phylogenetic analysis showed that all 52 VNNV isolates from cultured fish belong to the RGNNV genotype, but 2 out of 48 VNNV isolates from wild fish samples were found to be of the SJNNV genotype. This study is the first to confirm the existence of SJNNV-genotype VNNV in China. Golden pompano, an important fish species for culture, was selected as a fish model to investigate the optimal conditions for RGNNV disease progression in artificial infection experiments. The effects of temperature, salinity, and fish size were evaluated. Results showed that 28 °C and 20 ‰ are the optimal infection temperature and salinity, respectively, and golden pompano juveniles with small body sizes are more susceptible to RGNNV. These findings are highly consistent with those conditions involved in the natural outbreak of RGNNV.

Phenotypic plasticity in wild marine fishes associated with fish-cage aquaculture

Two opportunistic fish species associated with fish farms, bogue (Boops boops) and salema (Sarpa salpa), were studied to infer whether changes in their feeding habits may cause a phenotypic response in body and otolith shape. Specimens were collected close to aquaculture cage sites, called ‘wild-farmed fish’, and from control sites far away from these areas, called ‘wild fish’. The fish body shapes were examined with geometric morphometric analysis using 21 landmarks. The otolith contours were analysed using wavelet function, whereas otolith weights were used as indicators of fish growth rates. Statistically significant differences were observed in body shape between wild-farmed fish and wild fish of both species. The wild-farmed fish had a smaller head and eye, and in bogue also a slighter snout curvature and head depth. Otolith shape and weight did not differ between groups in bogue. By contrast, there were significant differences in otolith shape and weight between groups in salema. A complementary study in salema indicated that the wild-farmed fishes grew more in weight and accumulated higher concentrations of ‘terrestrial fatty acids’ (linoleic and alpha-linolenic acids), which are used in fish feeds. Our findings clearly demonstrated an influence of coastal sea cages on metabolism of some wild fishes.

Studies on Diseases caused by Isopods in relation to Bacterial Infection Among Some Wild Marine Fishes at Suez Canal Area

A total number 200 different marine fish species represented as 100 Elsarah (Nemipterus japonicus ) and 100 Mias (Pomatomus saltatrix L.) were collected seasonally from Suez and Ismailia provinces respectively . The infested marine fishes revealed no pathognomonic signs.They were investigated for detection of Isopoda parasites. It was revealed that 50% of the examined marine fishes was infested.The detected species were Irona nanodies from Nemipterus japonicus with a prevalence 60% , and Lironeca ovalis from Pomatomus saltatrix L with a prevalence 40%.The histopathological alterations were recorded and discussed.The secondary bacterial invasion was manifested by the isolation of Pseudomonas aeruginosa where it was experimentally infected into Tilapia zillii and reisolated again.

Characterization of Isolates of Streptococcus agalactiae from Diseased Farmed and Wild Marine Fish from the U.S. Gulf Coast, Latin America, and Thailand.

We examined Lancefield serogroup B Streptococcus isolates recovered from diseased, cultured hybrid Striped Bass (Striped Bass Morone saxatilis × White Bass M. chrysops) and wild and cultured Gulf Killifish Fundulus grandis from coastal waters of the U.S. Gulf of Mexico (Gulf coast) and compared those isolates to strains from tilapias Oreochromis spp. reared in Mississippi, Thailand, Ecuador, and Honduras and to the original Gulf coast strain identified by Plumb et al. ( 1974 ). The isolates were subjected to phylogenetic, biochemical, and antibiotic susceptibility analyses. Genetic analysis was performed using partial sequence comparison of (1) the 16S ribosomal RNA (rRNA) gene; (2) the sipA gene, which encodes a surface immunogenic protein; (3) the cspA gene, which encodes a cell surface-associated protein; and (4) the secY gene, which encodes components of a general protein secretion pathway. Phylogenies inferred from sipA, secY, and cspA gene sequence comparisons were more discriminating than that inferred from the 16S rRNA gene sequence comparison. The U.S. Gulf coast strains showed a high degree of similarity to strains from South America and Central America and belonged to a unique group that can be distinguished from other group B streptococci. In agreement with the molecular findings, biochemical and antimicrobial resistance analyses demonstrated that the isolates recovered from the U.S. Gulf coast and Latin America were more similar to each other than to isolates from Thailand. Three laboratory challenge methods for inducing streptococcosis in Gulf Killifish were evaluated-intraperitoneal (IP) injection, immersion (IMM), and immersion plus abrasion (IMMA)-using serial dilutions of S. agalactiae isolate LADL 97-151, a representative U.S. Gulf coast strain. The dose that was lethal to 50% of test fish by 14 d postchallenge was approximately 2 CFU/fish via IP injection. In contrast, the fish that were challenged via IMM or IMMA presented cumulative mortality less than 40% by 14 d postchallenge.

Heavy metal concentrations in wild fishes captured from the South China Sea and associated health risks

Heavy metal concentrations were measured in 29 marine wild fish species from the South China Sea. Concentrations (wet weight) were 0.51–115.81ng/g (Cd), 0.54–27.31ng/g (Pb), 0.02–1.26μg/g (Cr), 8.32–57.48ng/g (Ni), 0.12–1.13μg/g (Cu), 2.34–6.88μg/g (Zn), 2.51–22.99μg/g (Fe), and 0.04–0.81μg/g (Mn), respectively. Iron concentrations in all and Mn in some fish species were higher than the acceptable daily upper limit, suggesting human consumption of these wild fish species may pose a health risk. Human health risk assessment, however, indicated no significant adverse health effects with consumption.

Heavy metals in wild marine fish from South China Sea: levels, tissue- and species-specific accumulation and potential risk to humans

Heavy metal pollution in marine fish has become an important worldwide concern, not only because of the threat to fish in general, but also due to human health risks associated with fish consumption. To investigate the occurrence of heavy metals in marine fish species from the South China Sea, 14 fish species were collected along the coastline of Hainan China during the spring of 2012 and examined for species- and tissue-specific accumulation. The median concentrations of Cd, Cr, Cu, Zn, Pb and As in muscle tissue of the examined fish species were not detectable (ND), 2.02, 0.24, 2.64, 0.025, and 1.13 mg kg(-1) wet weight, respectively. Levels of Cu, Zn, Cd and Cr were found to be higher in the liver and gills than in muscle, while Pb was preferentially accumulated in the gills. Differing from other heavy metals, As did not exhibit tissue-specific accumulation. Inter-species differences of heavy metal accumulation were attributed to the different habitat and diet characteristics of marine fish. Human dietary exposure assessment suggested that the amounts of both Cr and As in marine wild fish collected from the sites around Hainan, China were not compliant with the safety standard of less than 79.2 g d(-1) for wild marine fish set by the Joint FAO/WHO Expert Committee on Food Additives. Further research to identify the explicit sources of Cr and As in marine fish from South China Sea should be established.

Comparison of mercury bioaccumulation between wild and mariculture food chains from a subtropical bay of Southern China.

Bioaccumulation and trophic transfer of mercury (Hg) both in the natural marine ecosystem and the mariculture ecosystem were studied at Daya Bay, a subtropical bay in Southern China. Averaged Hg concentrations in sediment, phytoplankton, macrophyte, shrimp, crab, shellfish, planktivorous fish, carnivorous fish, farmed pompano, farmed snapper, compound feed and trash fish were 0.074, 0.054, 0.044, 0.098, 0.116, 0.171, 0.088, 0.121, 0.210, 0.125, 0.038 and 0.106μgg(-1)dw, respectively. These Hg levels were at the low-middle ends of the global range. Positive correlation between Hg concentrations in farmed fish and fish weights/sizes was observed, whereas no clear correlation between Hg concentrations and lipid contents was found. Hg concentrations followed macrophyte<phytoplankton<sediment<planktivorous fish<shrimp<crab<carnivorous fish<shellfish, and commercial feed<trash fish<farmed fish. Hg was biomagnified along the marine food chain in the ecosystem of Daya Bay. Hg levels in the farmed fish were higher than those in the wild fish primarily because of the higher Hg level in fish feed and the smaller size of marine wild fish.

An Updated Checklist Of Parasitic Helminths Of Marine Fish From Turkey

Abstract An updated checklist carried out indicated the occurrence of 161 helminth species from wild marine fish species in Turkey, which includes 49 monogeneans, 63 digeneans, 18 cestodes, 17 nematodes, 11 acanthocephalans and three annelids, from 88 different fish (86 native, two migratory) species. Since the publication of the checklist of helminth parasites of marine fishes in Turkey over nine years ago (Öktener, 2005), there have been a number of new records. This update includes these additional records and has allowed the correction of those errors and omissions that were present in the previous version. The parasite species list is arranged by phylum and class, providing parasite species name, host fish, location of host fish capture and author, and date of published record. The host list consists of all parasite species listed by host species. All parasites and their hosts are confirmed with the recent systematic accounts and full taxonomic account.

Characteristics of nonylphenol and bisphenol A accumulation by fish and implications for ecological and human health

Fish populations constitute an important part of aquatic ecosystems. Thus, their accumulation of nonylphenol (NP) and bisphenol A (BPA) may pose risks to ecosystems and human health. This study analyzed the concentrations of NP and BPA in four types of fishes (i.e., wild/farmed freshwater fishes and wild/farmed marine fishes). Wild freshwater fishes contained higher concentrations of NP and BPA than the other three types of fishes. The concentrations of NP in the wild freshwater fishes ranged from 1.01 to 277μg/kg ww, with bioconcentration factors (BCFs) and biota–sediment accumulation factors (BSAFs) ranging from 74.0 to 2.60×104L/kg and from 0.003 to 18.3, respectively. The wild freshwater fishes contained relatively low amounts of BPA, varying from ND to 25.2μg/kg ww, with the BCFs and BSAFs ranging from 1.00 to 274L/kg and from 0.003 to 3.40, respectively. Five fish species particularly showed high BCFs and BSAFs, indicating that they could be an important source of NP for higher trophic levels, most likely resulting in ecological risks. The demersal fishes showed a greater ability to accumulate NP than the pelagic ones. The fact that the 95th percentile values of the risk quotient (RQ) for NP and BPA were higher than the acceptable threshold indicated that these two compounds would have adverse effects on aquatic organisms in Taiwanese rivers. The consumption of wild marine fishes had the highest 95th percentile values of hazard quotient (HQ) for NP and BPA among the four types of fishes, particularly for the population aged 0–3years. However, the 95th percentile values of HQ for NP and BPA were all less than 1, suggesting that exposure to NP and BPA through fish consumption posed no remarkable risk to human health in Taiwan.

Screening for viral hemorrhagic septicemia virus in marine fish along the Norwegian coastal line.

Viral hemorrhagic septicemia virus (VHSV) infects a wide range of marine fish species. To study the occurrence of VHSV in wild marine fish populations in Norwegian coastal waters and fjord systems a total of 1927 fish from 39 different species were sampled through 5 research cruises conducted in 2009 to 2011. In total, VHSV was detected by rRT-PCR in twelve samples originating from Atlantic herring (Clupea harengus), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and silvery pout (Gadiculus argenteus). All fish tested positive in gills while four herring and one silvery pout also tested positive in internal organs. Successful virus isolation in cell culture was only obtained from one pooled Atlantic herring sample which shows that today's PCR methodology have a much higher sensitivity than cell culture for detection of VHSV. Sequencing revealed that the positive samples belonged to VHSV genotype Ib and phylogenetic analysis shows that the isolate from Atlantic herring and silvery pout are closely related. All positive fish were sampled in the same area in the northern county of Finnmark. This is the first detection of VHSV in Atlantic herring this far north, and to our knowledge the first detection of VHSV in silvery pout. However, low prevalence of VHSV genotype Ib in Atlantic herring and other wild marine fish are well known in other parts of Europe. Earlier there have been a few reports of disease outbreaks in farmed rainbow trout with VHSV of genotype Ib, and our results show that there is a possibility of transfer of VHSV from wild to farmed fish along the Norwegian coast line. The impact of VHSV on wild fish is not well documented.

A survey of wild marine fish identifies a potential origin of an outbreak of viral haemorrhagic septicaemia in wrasse, Labridae, used as cleaner fish on marine Atlantic salmon, Salmo salar L., farms.

Viral haemorrhagic septicaemia virus (VHSV) was isolated from five species of wrasse (Labridae) used as biological controls for parasitic sea lice predominantly, Lepeophtheirus salmonis (Krøyer, 1837), on marine Atlantic salmon, Salmo salar L., farms in Shetland. As part of the epidemiological investigation, 1400 wild marine fish were caught and screened in pools of 10 for VHSV using virus isolation. Eleven pools (8%) were confirmed VHSV positive from: grey gurnard, Eutrigla gurnardus L.; Atlantic herring, Clupea harengus L.; Norway pout, Trisopterus esmarkii (Nilsson); plaice, Pleuronectes platessa L.; sprat, Sprattus sprattus L. and whiting, Merlangius merlangus L. The isolation of VHSV from grey gurnard is the first documented report in this species. Nucleic acid sequencing of the partial nucleocapsid (N) and glycoprotein (G) genes was carried out for viral characterization. Sequence analysis confirmed that all wild isolates were genotype III the same as the wrasse and there was a close genetic similarity between the isolates from wild fish and wrasse on the farms. Infection from these local wild marine fish is the most likely source of VHSV isolated from wrasse on the fish farms.

Strong winds, upwelling, and teeming shores

Climate Change Climate warming has produced stronger winds along some coasts, a result of growing differences in temperature and pressure between land and sea. These winds cause cold nutrient-rich seawater to rise to the surface, affecting climate and fueling marine productivity. Sydeman et al. examined data from the five major world regions where upwelling is occurring. Particularly in the California, Humboldt, and Benguela upwelling systems, winds have become stronger over the past 60 years. These regions represent up to a fifth of wild marine fish catches and are hot spots of biodiversity. Science , this issue p. [77][1] [1]: /lookup/doi/10.1126/science.1251635

Infections of nervous necrosis virus in wild and cage-reared marine fish from South China Sea with unexpected wide host ranges.

The concerns about the impact of the nervous necrosis virus (NNV) infections in wild fish have been raised. This paper presents the results of quarterly surveys of NNV in wild and cage-reared marine fish from South China Sea. Samples of 892 wild fish belonging to 69 species and 381 cage-reared fish belonging to 11 species were collected and were detected by seminested PCR and nested PCR. In the case of seminested PCR, the positive signal was detected in 3.0% and 3.1% samples of wild and cage-reared fish, respectively. However, by nested RT-PCR, the positive signal was observed in 42.3% and 63.0% samples of wild and cage-reared fish, respectively. If the fish species were considered, the positive signal was detected in 21.7% and 72.7% species of wild and cage-reared fish by seminested PCR assay, respectively. However, by nested RT-PCR, the positive signal was observed in 65.2% and 100% species of wild and cage-reared fish, respectively. The nucleotide sequences of the nested PCR products were determined. Phylogenetic tree showed that all the obtained viral isolates belonged to the red-spotted grouper nervous necrosis virus (RGNNV) genotype. Thirty-five species of the marine fish were the new hosts of NNV.

Effect of Anisakis simplex (sl) larvae on the spoilage rate and shelf-life of fish mince products under laboratory conditions

Wild caught marine fish are commonly infected with anisakid nematodes lodging in the intestinal linings or in the fish muscle. One of the most commonly found nematode parasites in marine fish is Anisakis simplex. During production of mince from the muscle of wild caught Anisakis-infected fish, the larvae would be disrupted during mince production. Any bacteria within or on the surface of such larvae are during the mincing process evenly distributed throughout the mince, and could thus possibly affect the spoilage rate of the final products. To explore if or how any bacteria associated with muscle-invading Anisakis larvae may affect the spoilage rate of fish mince, a controlled storage trial was conducted. Fillets of farmed Atlantic cod (Gadus morhua), exclusively fed on dried and heat-treated compound feed and hence expectably free from Anisakis larvae, were aseptically collected and homogenised. Fish mince aliquots were added different volumes of Anisakis homogenate based on larvae which were freshly sampled from the visceral cavity of NE Atlantic blue whiting (Micromesistius poutassou). The volumes of added parasite homogenate (parasite(þ)-samples) reflected different infection intensities from 15 (low) to 50 (high) larvae per 100 g fish fillet, representing an actual Anisakis intensity range in the flesh of blue whiting. The samples were kept at 4 � C for 15 days and subjected to microbiological, sensory and chemical evaluation at 3 days intervals. Upon visual examination and plate count measurements (PC) on Iron Agar Lyngby (IAL), the samples without any parasite additives (no[parasite]) spoiled differently and more rapidly than any of the parasite(þ)-samples. However, H2S-producing bacteria were only recorded in the latter samples, which were also the only ones that showed increased levels of the spoilage indicator substance trimethylamine (TMA). Moreover, the parasite(þ)-samples changed their sensory characteristics at a later stage compared to the no[parasite]-samples. Although some cultures of H2Sproducing bacteria were found on IAL, molecular identification by PCR-DGGE of the actual bacteria was not conclusive. Psychrobacter sp. which has no or only little spoilage activity, was identified in all samples until trial day 9, but was probably outgrown by the stronger spoilers Pseudomonas fluorescence/fragi and Photobacterium phosphoreum. Thus, and somewhat unexpected, our findings indicate that e under the present trial conditions e fish mince contaminated with bacteria which originate from Anisakis larvae, spoiled less rapidly than samples without any parasite-related bacteria present. Moreover, the shelf-life of fish mince was apparently not reduced by the presence of bacteria transferred to the mince by Anisakis larvae.

Survey of viral haemorrhagic septicaemia virus in wild fishes in the southeastern Black Sea.

Species diversity in the Black Sea ecosystem has been declining rapidly over the last 2 decades. To assess the occurrence and distribution of viral haemorrhagic septicaemia virus (VHSV) in various wild fish species, a wild marine fish survey was carried out in 2009, 2010, and 2011. The pooled or individual samples of kidney, liver, and spleen of 5025 specimens, belonging to 17 fish species, were examined virologically using cell culture. The cells showing cytopathic effects (CPE) were subjected to ELISA and multiplex reverse transcriptase polymerase chain reaction (RT-mPCR), for VHSV and infectious pancreatic necrosis virus (IPNV), after blind passaging to determine the virus species causing CPE. The virus species and possibility of co-infection with IPNV were verified by the RT-mPCR developed in this study. Twelve species of fish (pontic shad Alosa immaculata, red mullet Mullus barbatus, three-bearded rockling Gaidropsarus vulgaris, black scorpionfish Scorpaena porcus, Mediterranean horse mackerel Trachurus mediterraneus, whiting Merlangius merlangus euxinus, stargazer Uranoscopus scaber, pilchard Sardina pilchardus, garfish Belone belone, round goby Neogobius melanostomus, thornback ray Raja clavata, and anchovy Engraulis encrasicolus) tested positive for VHSV Genotype Ie (VHSV-Ie). Except whiting, pilchard, and round goby, the rest are new host records for VHSV. The extent and spread of VHSV-Ie was significantly higher among bottom fish than among pelagic fish. Sensitivity and specificity of the RT-mPCR developed was sufficiently high, suggesting that this assay may be used for both diagnostic and surveillance testing. According to the RT-mPCR results, IPNV was not present in wild fish. These results support the hypothesis that the VHSV-Ie genotype, highly prevalent among fish species in the Black Sea, may have a serious impact on the population dynamics of wild fish stocks.

Individual variations in fatty acid composition and concentration as indicators of the nutritional condition of wild pointhead flounder larvae

We investigated the fatty acid compositions and concentrations of wild marine fish larvae with a highly accurate method because our knowledge of them has been seriously limited compared with cultured larvae. This study presents estimates of the fatty-acid-based nutritional condition of individual larvae in the field. Because the pointhead flounder Cleisthenes pinetorum displays relatively high stock size fluctuations, we investigated the developmental change in the fatty acid compositions of the body trunk, head, and eye and the annual fluctuations in the fatty acid concentrations in the trunk. We show that the process of fatty acid accumulation is not uniform across body parts and that the trunk is a better indicator of larval nutritional status than other parts because there is less time lag. Starved larvae with simultaneously high docosahexaenomic acid ratios and low total fatty acid concentrations, as observed in laboratory experiments, are rare in the wild. Thus, starved larvae must be removed rapidly by predators before they can experience a relatively long period of starvation in the wild. Fatty acid accumulation was greater in the larvae of the 2005 year class than in those of the 2006 year class in their first feeding stage, according to the optimal model derived with generalized linear model. A previous study indicated that the 2005 year class showed stronger recruitment than the 2006 year class. We conclude that the fatty acid analysis of wild larvae is a useful index of their nutritional status and mortality, especially in the first feeding stage.