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Marine Fish (marine + fish)
Terms modified by Marine Fish Selected AbstractsDocumenting Loss of Large Trophy Fish from the Florida Keys with Historical PhotographsCONSERVATION BIOLOGY, Issue 3 2009LOREN McCLENACHAN arrecifes de coral; ecología histórica; directrices cambiantes; peces de arrecife; sobrepesca Abstract:,A loss of large vertebrates has occurred in aquatic and terrestrial ecosystems, but data to measure long-term population changes are sparse. Historical photographs provide visual and quantitative evidence of changes in mean individual size and species composition for groups of marine fish that have been targeted by sport fishing. I measured such trends for 13 groups of recreationally caught "trophy" reef fish with photographs taken in Key West, Florida, from 1956 to 2007. The mean fish size declined from an estimated 19.9 kg (SE 1.5) to 2.3 kg (SE 0.3), and there was a major shift in species composition. Landings from 1956 to 1960 were dominated by large groupers (Epinephelus spp.), and other large predatory fish were commonly caught, including sharks with an average length of just <2 m. In contrast, landings in 2007 were composed of small snappers (Lutjanus spp. and Ocyurus chrysurus) with an average length of 34.4 cm (SE 0.62), and the average length of sharks declined by more than 50% over 50 years. Major declines in the size of fish caught were not reflected in the price of fishing trips, so customers paid the same amount for a less-valuable product. Historical photographs provide a window into a more pristine coral reef ecosystem that existed a half a century ago and lend support to current observations that unfished reef communities are able to support large numbers of large-bodied fish. Resumen:,Una pérdida de vertebrados mayores ha ocurrido en ecosistemas acuáticos y terrestres, pero los datos para medir los cambios poblaciones a largo plazo son escasos. Las fotografías históricas proporcionan evidencia visual y cuantitativa de cambios en el tamaño individual promedio y de la composición de especies en grupos de peces marinos que han sido blanco de la pesca deportiva. Medí esas tendencias en 13 grupos de peces de arrecife capturados recreativamente como "trofeos" mediante fotografías tomadas en Key West, Florida, desde 1956 a 2007. El peso promedio de los peces declinó de unos 19.9 kg (ES 1.5) a 2.3 kg (ES 0.3), y hubo un cambio mayor en la composición de especies. Las capturas entre 1956 y 1960 estuvieron dominadas por meros (Epinephelus spp.) grandes, y otros peces depredadores eran capturados comúnmente, incluyendo tiburones con una longitud promedio de poco menos de 2m. En contraste, las capturas en 2007 fueron compuestas de pargos (Lutjanus spp. y Ocyurus chrysurus) pequeños con una longitud promedio de 34.4 cm (ES 0.62), y la longitud promedio de los tiburones declinó más de 50% en 50 años. La gran declinación en el tamaño de los peces capturados no se reflejó en los precios de los viajes de pesca, así que los clientes pagaron la misma cantidad por un producto menos valioso. Las fotografías históricas proporcionan una visión de un ecosistema arrecifal coralino prístino que existió hace medio siglo y proporcionan soporte a los comentarios actuales de que las comunidades arrecifales no explotadas son capaces de soportar numerosos peces de talla grande. [source] Co-occurrence of ectoparasites of marine fishes: a null model analysisECOLOGY LETTERS, Issue 1 2002Nicholas J. Gotelli We used null model analysis to test for nonrandomness in the structure of metazoan ectoparasite communities of 45 species of marine fish. Host species consistently supported fewer parasite species combinations than expected by chance, even in analyses that incorporated empty sites. However, for most analyses, the null hypothesis was not rejected, and co-occurrence patterns could not be distinguished from those that might arise by random colonization and extinction. We compared our results to analyses of presence,absence matrices for vertebrate taxa, and found support for the hypothesis that there is an ecological continuum of community organization. Presence,absence matrices for small-bodied taxa with low vagility and/or small populations (marine ectoparasites, herps) were mostly random, whereas presence,absence matrices for large-bodied taxa with high vagility and/or large populations (birds, mammals) were highly structured. Metazoan ectoparasites of marine fishes fall near the low end of this continuum, with little evidence for nonrandom species co-occurrence patterns. [source] Linear alkylbenzenes in muscle tissues of white croaker near a large ocean outfall in southern California, USAENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2001Charles R. Phillips Abstract Muscle tissues of a bottom-dwelling marine fish, white croaker (Genyonemus lineatus), collected near a large wastewater outfall in southern California, USA, were analyzed for long-chain linear alkylbenzenes (LABs). Total LABs (summed concentrations of C11 through C14 isomers) were highest (166,748 ng g,1 wet wt) in individuals collected in the immediate vicinity of the Orange County Sanitation District (OCSD; Fountain Valley, CA, USA) outfall diffuser, whereas relatively lower concentrations occurred in fish from mid-shelf and inshore locations at distances of 2.5 and 5 km, respectively, from the outfall. Fish tissue LAB concentrations were roughly proportional to sediment LAB concentrations at the respective collection sites. The extent of LAB degradation, as determined by ratios of internal to external C12 isomers, did not appear to relate to LAB concentrations or sampling location. Tissue DDT and PCB concentrations were not significantly correlated with LABs and, thus, did not appear to relate to recent exposures to sewage residues from the OCSD discharge. Measurements of LAB concentrations in fish tissues may be widely applicable as a monitoring tool for interpreting exposures to sewage discharges. [source] Identification, structure and differential expression of novel pleurocidins clustered on the genome of the winter flounder, Pseudopleuronectes americanus (Walbaum)FEBS JOURNAL, Issue 18 2003Susan E. Douglas Antimicrobial peptides form one of the first lines of defense against invading pathogens by killing the microorganisms and/or mobilizing the host innate immune system. Although over 800 antimicrobial peptides have been isolated from many different species, especially insects, few have been reported from marine fish. Sequence analysis of two genomic clones (15.6 and 12.5 kb) from the winter flounder, Pseudopleuronectes americanus (Walbaum) resulted in the identification of multiple clustered genes for novel pleurocidin-like antimicrobial peptides. Four genes and three pseudogenes (,) are encoded in these clusters, all of which have similar intron/exon boundaries but specify putative antimicrobial peptides differing in sequence. Pseudogenes are easily detectable but have incorrect initiator codons (ACG) and often contain a frameshift(s). Potential promoters and binding sites for transcription factors implicated in regulation of expression of immune-related genes have been identified in upstream regions by comparative genomics. Using reverse transcription-PCR assays, we have shown for the first time that each gene is expressed in a tissue-specific and developmental stage-specific manner. In addition, synthetic peptides based on the sequences of both genes and pseudogenes have been produced and tested for antimicrobial activity. These data can be used as a basis for prediction of antimicrobial peptide candidates for both human and nonhuman therapeutants from genomic sequences and will aid in understanding the evolution and transcriptional regulation of expression of these peptides. [source] Genetic population structure of marine fish: mismatch between biological and fisheries management unitsFISH AND FISHERIES, Issue 4 2009Henning Reiss Abstract An essential prerequisite of a sustainable fisheries management is the matching of biologically relevant processes and management action. In fisheries management and assessment, fish stocks are the fundamental biological unit, but the reasoning for the operational management unit is often indistinct and mismatches between the biology and the management action frequently occur. Despite the plethora of population genetic data on marine fishes, to date little or no use is made of the information, despite the fact that the detection of genetic differentiation may indicate reproductively distinct populations. Here, we discuss key aspects of genetic population differentiation in the context of their importance for fisheries management. Furthermore, we evaluate the population structure of all 32 managed marine fish species in the north-east Atlantic and relate this structure to current management units and practice. Although a large number of studies on genetic population structure have been published in the last decades, data are still rare for most exploited species. The mismatch between genetic population structure and the current management units found for six species (Gadus morhua, Melanogrammus aeglefinus, Merlangius merlangus, Micromesistius poutassou, Merluccius merluccius and Clupea harengus), emphasizes the need for a revision of these units and questions the appropriateness of current management measures. The implementation of complex and dynamic population structures into novel and less static management procedures should be a primary task for future fisheries management approaches. [source] Fish venom: pharmacological features and biological significanceFISH AND FISHERIES, Issue 2 2009Gisha Sivan Abstract Nearly 1200 species of marine fish are venomous and they account for two-third of the population of venomous vertebrates. Fish venoms are focused as a potential source of pharmacological agents and physiological tools that have evolved to target vital processes in the human body that appear to have more electivity than many drugs. Fish venoms possess cardiovascular, neuromuscular, oedematic and cytolytic activity. Lethal toxins have been isolated and purified, with some having LD50 values comparable to that of snake venoms. Cardiovascular activity seems to be the dominant effect of fish venoms in experimental models. Piscine venom acts both pre- and post-junctionally to produce depolarization of cell membranes. Studies on cytolytic activity of fish venom found that it produces lysis by forming hydrophilic pores in cell membranes which then result in cell lysis. Almost all fish venoms with neuromuscular activity also possesses cytolytic activity, and it is very likely that the two activities are related. Fish venom is known to induce intense and sustained edematogenic response. As piscine venoms have evolved for the same purpose, they show a number of similarities pharmacologically and it seems likely that most of the biological activities of any given toxin can be traced back to its cytolytic activity. A variety of toxins have been isolated from piscine venom. Although there is a complex balance between the components present in the venom of different fish, all of them seem to share similar activity , functionally and pharmacologically as well as structurally. [source] A new approach to prioritizing marine fish and shellfish populations for conservationFISH AND FISHERIES, Issue 4 2001Einar Eg Nielsen Abstract There has been increasing awareness of the vulnerability of marine organisms to population extirpation and species extinction. While very few documented cases of species extinction exist in the marine environment, it is anticipated that managers will face the dilemma of prioritizing populations of marine fish and shellfish for protection in the near future. Current prioritization procedures have been developed from salmonid models with the intent of applying them to all marine organisms, and in some cases to freshwater and terrestrial taxa. In this review we provide evidence for the relevance of such a process for marine species and further suggest five broad categories of marine organisms that have distinctive traits influencing their genetic structure. The current prioritization models have been adapted to account for each of these species groups. Emphasis is placed on ,Classical Marine Species' which represent the opposite end of the continuum from the salmon model, displaying high within-population genetic variance. From this category, three cod (Gadus morhua) stocks were selected to evaluate a revised scheme developed specifically for ,Classical Marine Species' that includes performance measures such as (i) reduction in number of spawning populations; (ii) reduction of Ne : Nc (ratio of effective to census population size); (iii) changes in life-history traits; (iv) critical density for spawning success; and (v) patchy vs. continuous distribution pattern. When the salmonid scheme was applied, the cod examples were allocated low values, indicating that they were not under threat. However, when the revised scheme was applied, all three cod stocks were allocated high values, indicating that the revised scheme was more reflective of the particular life-history traits of this category of organisms. [source] Low-temperature-driven early spawning migration of a temperate marine fishJOURNAL OF ANIMAL ECOLOGY, Issue 2 2004David W. Sims Summary 1It is often assumed that the timing of annual migrations of marine fish to spawning grounds occurs with very little change over time. However, it is unclear how much migration is influenced by climate change in marine species that spawn at sea but spend most time in estuarine conditions, especially as thermal regimes in estuaries may differ significantly from those in the open sea. 2Migration phenology was studied in a population of flounder, Platichthys flesus (L.) off south-west England using high-temporal resolution trawling data over a 13-year period. 3Flounder migrated from their estuarine habitat to spawning grounds at sea some 1,2 months earlier in years that were up to 2 °C cooler. Flounder arrived on the spawning grounds over a shorter time period (2,6 days) when colder than normal conditions prevailed in the estuary, compared to warmer years (12,15 days). This suggests that they were responding to low temperatures by exhibiting a more synchronous, population-level early migration. 4The timing of migration was earlier when the largest differences in temperatures between near-estuary and offshore environments occurred, differences that were related significantly to cold, negative phases of the North Atlantic Oscillation (NAO). 5Flounder migration phenology appears to be driven to a large extent by short-term, climate-induced changes in the thermal resources of their overwintering habitat. This suggests that climate fluctuations characterizing the NAO may have significant effects on the timing of the peak abundance of fish populations generally, which, in turn, may have implications for fisheries management. [source] Ammonia in estuaries and effects on fishJOURNAL OF FISH BIOLOGY, Issue 6 2005F. B. Eddy This review aims to explore the biological responses of fish in estuaries to increased levels of environmental ammonia. Results from laboratory and field studies on responses of fish to varying salinity and their responses increased ammonia will be evaluated, although studies which examine responses to ammonia, in relation to varying salinity, pH and temperature together are rare. In a survey of British estuaries the continuous measurement of total ammonia showed values that ranged from background levels increasing up to c. 10 mg N l,1 although higher values have been noted sporadically. In outer estuaries pH values tended to stabilize towards sea water values (e.g. c. pH 8). Upper reaches of estuaries are influenced by the quality of their fresh waters sources which can show a wide range of pH and water quality values depending on geological, climatic and pollution conditions. In general the ammonia toxicity (96 h LC50) to marine species (e.g. 0·09,3·35 mg l,1 NH3) appears to be roughly similar to freshwater species (e.g. 0·068,2·0 mg l,1 NH3). Ammonia toxicity is related to differences between species and pH rather than to the comparatively minor influences of salinity and temperature. In the marine environment the toxicity of ionized ammonia should be considered. The water quality standard for freshwater salmonids of 21 ,g l,1 NH3,N was considered to be protective for most marine fish and estuarine fish although the influence of cyclical changes in pH, salinity and temperature were not considered. During ammonia exposures, whether chronic or episodic, estuarine fish may be most at risk as larvae or juveniles, at elevated temperatures, if salinity is near the seawater value and if the pH value of the water is decreased. They are also likely to be at risk from ammonia intoxication in waters of low salinity, high pH and high ammonia levels. These conditions are likely to promote ammonia transfer from the environment into the fish, both as ionized and unionized ammonia, as well as promoting ammonia retention by the fish. Fish are more likely to be prone to ammonia toxicity if they are not feeding, are stressed and if they are active and swimming. Episodic or cycling exposures should also be considered in relation to the rate at which the animal is able to accumulate and excrete ammonia and the physiological processes involved in the transfer of ammonia. In the complex environment of an estuary, evaluation of ammonia as a pollutant will involve field and laboratory experiments to determine the responses of fish to ammonia as salinity and temperature vary over a period of time. It will also be necessary to evaluate the responses of a variety of species including estuarine residents and migrants. [source] Distribution of genetic variation in farmed and natural stocks of european eelJOURNAL OF FISH BIOLOGY, Issue 2004J. M. Pujolar European eel (Anguilla anguilla; Teleostei) is a valuable commercial species. However, over the past 25 years, the population of European eel has been declining to such a degree that major concerns have been raised for its long-term conservation. Since little information is available on the life-cycle and genetic structure of European eel, it has been difficult to evaluate the existence of any population substructuring. Molecular genetic methods contribute to a better knowledge of the demography and population structure in marine fish. In addition, management strategies and conservation goals must consider information on genetic substructuring as well as on life history patterns. The aim of the study is to provide more detailed knowledge on the genetic variability, demography and population substructuring of European eel by analysing and comparing natural and farmed individuals. Natural eel samples have been obtained in two geographical sites (Netherlands, France) including temporal samples in a short-scale (within years) and a long-scale (between years). Simultaneously, farmed glass eels have been grown in two separate batches during one year. Batches have been monitored and genetic samples have been obtained during the year. A combination of selection-sensitive (allozymes) and selection-neutral markers (microsatellites) has been used in the study since selection seems to play an important role in the determination of the quality of future eel spawners. Results suggest a positive correlation between growth and genetic variability since individuals attaining a large length and mass present significant higher heterozygosities. [source] Activity of the antimicrobial polypeptide piscidin 2 against fish ectoparasitesJOURNAL OF FISH DISEASES, Issue 6 2008A Colorni Abstract The antiparasitic effects of piscidin 2, an antimicrobial polypeptide (AMPP) first isolated from mast cells of hybrid striped bass, were tested against three protistan ectoparasites of marine fish (the ciliates Cryptocaryon irritans and Trichodina sp., and the dinoflagellate Amyloodinium ocellatum) and one ciliate ectoparasite of freshwater fish (Ichthyophthirius multifiliis). I. multifiliis was the most susceptible parasite, with all theronts killed at 6.3 ,g mL,1 piscidin 2. The most resistant parasite was Trichodina, where a few cells were killed at 12.5 ,g mL,1, but several were still alive even at 100 ,g mL,1. C. irritans was of intermediate sensitivity, with some theronts killed at 12.5 ,g mL,1 and all killed at 25 ,g mL,1. High parasite density apparently exhausted the piscidin 2 before it could attain its maximal effect, but surviving parasites were often visibly damaged. The lower efficacy of piscidin 2 against marine parasites compared with the freshwater ciliate might be related to the inhibitory effects of high sea water cation levels. The tissue concentration of piscidins estimated in healthy hybrid striped bass gill (40 ,g mL,1) suggests that piscidin 2 is lethal to the parasites tested at physiological concentrations and is thus an important component of innate defence in fish expressing this type of AMPP. [source] Distribution of infectious pancreatic necrosis virus (IPNV) in wild marine fish from Scottish waters with respect to clinically infected aquaculture sites producing Atlantic salmon, Salmo salar L.JOURNAL OF FISH DISEASES, Issue 3 2008I S Wallace Abstract This study represents the first large-scale investigation of IPNV in Scottish wild marine fish. Kidney samples were taken from 30 627 fish comprising 37 species and 45 isolations were made from nine different species, illustrating these as reservoirs of IPNV in Scottish waters. The estimated prevalence of IPNV in the Scottish marine environment was low at 0.15% (90% confidence intervals, (CI) of 0.11,0.19%). This was significantly greater in fish caught less than 5.0 km from IPN-positive fish farms in Shetland, at 0.58% (90% CI of 0.45,0.77%). This prevalence persisted and did not significantly decrease over the 16-month period of study. The estimated prevalence of IPNV for each positive species was less than 1% with the statistically non-significant exceptions of flounder, Platichthys flesus (L.), at 12.5% (90% CI of 0.64,47.06%) and saithe, Pollachius virens (L.), at 1.11% (90% CI of 0.49,2.19%). The 45 isolates were titrated and all but two were below the detection limit of the test (<55 PFU g,1). Titres of 3.8 × 102 PFU g,1 and 2.8 × 101 PFU g,1 were calculated from common dab, Limanda limanda (L.), and saithe, respectively. This study provides evidence that clinical outbreaks of IPN in farmed Atlantic salmon may cause a localized small increase in the prevalence of IPNV in wild marine fish. [source] Investigation of wild caught whitefish, Coregonus lavaretus (L.), for infection with viral haemorrhagic septicaemia virus (VHSV) and experimental challenge of whitefish with VHSVJOURNAL OF FISH DISEASES, Issue 7 2004H F Skall Abstract One hundred and forty-eight wild whitefish, Coregonus lavaretus (L.), were caught by electrofishing and sampled for virological examination in December 1999 and 2000, during migration from the brackish water feeding grounds to the freshwater spawning grounds, where the whitefish may come into contact with farmed rainbow trout. All samples were examined on cell cultures. No viruses were isolated. Three viral haemorrhagic septicaemia virus (VHSV) isolates of different origin were tested in infection trials by immersion and intraperitoneal (IP) injection, using 1.5 g farmed whitefish: an isolate from wild caught marine fish, a farmed rainbow trout isolate with a suspected marine origin and a classical freshwater isolate. The isolates were highly pathogenic by IP injection where 99,100% of the whitefish died. Using an immersion challenge the rainbow trout isolates were moderately pathogenic with approximately 20% mortality, whereas the marine isolate was virtually non-pathogenic. At the end of the experiment it was possible to isolate VHSV from survivors infected with the marine and suspected marine isolates. Because of the low infection rate in wild whitefish in Denmark, the role of whitefish in the spread of VHSV in Denmark is probably not significant. The experimental studies, however, showed that whitefish are potential carriers of VHSV as they suffer only low mortality after infection but continue to carry virus. [source] Ribosomal DNA sequences indicate isolated populations of Ichthyophonus hoferi in geographic sympatry in the north-eastern Pacific OceanJOURNAL OF FISH DISEASES, Issue 10 2002C D Criscione Abstract Infections of Ichthyophonus hoferi, a cosmopolitan parasite of marine fish, have recently been reported in rockfish, Sebastes spp., from the north-eastern Pacific. Because I. hoferi also infects Pacific herring, Clupea pallasi Valenciennes, and salmonids in this region, we wanted to determine if Ichthyophonus parasites from rockfishes, Pacific herring and chinook salmon, Oncorhynchus tshawytscha (Walbaum), were the same. Small subunit ribosomal deoxyribonucleic acid sequence data revealed two haplotypes that were fixed among host species in geographic sympatry, one from rockfish and the other from both Pacific herring and salmon. These isolated populations of Ichthyophonus could be part of the same species that are ecologically separated because of host behaviours, or they could be distinct species that are host specific. Dietary patterns of the hosts indicate that ecological separation among hosts is possible, but the presence of distinct species may better explain the observed Ichthyophonus haplotype association with host species. [source] Gill disease of marine fish caused by infection with Neoparamoeba pemaquidensisJOURNAL OF FISH DISEASES, Issue 9 2001B L Munday Amoebic gill disease (AGD) of maricultured salmonids, turbot, Scophthalmus maximus (L.), European seabass, Dicentrarchus labrax (L.), and sharpsnout seabream, Diplodus puntazzo (Cetti), caused by Neoparamoeba pemaquidensis has been reported from Australia (Tasmania), Ireland, France, Chile, North America (Washington State and California) and Spain. Of the salmonids, Atlantic salmon, Salmo salar L., appears to be the most susceptible with rainbow trout, Oncorhynchus mykiss (Walbaum), also suffering significant disease. Only minor outbreaks have been reported in coho, O. kisutch (Walbaum), and chinook salmon, O. tshawytscha (Walbaum). The disease now accounts for 10,20% of production costs of Atlantic salmon in Tasmania and has lead to temporary abandonment of culture of this species in parts of Spain. It is of lesser, but still significant, importance in other countries. Much is known about the pathology of AGD but the pathophysiology of the disease is poorly understood. There is evidence that non-specific immunity is involved in fish acquiring resistance to AGD, but no unequivocal evidence exists for protection as a result of specific immune responses. To date, for salmonids, the only effective treatment for AGD is a freshwater bath. Control procedures based on modification of management strategies have been minimal and virtually unresearched. [source] MICROBIOLOGICAL AND PATHOGENIC CONTAMINANTS OF SEAFOOD IN GREECEJOURNAL OF FOOD QUALITY, Issue 1 2007C. PAPADOPOULOU ABSTRACT A total of 360 samples, including 105 marine fish, 25 prawns, 50 squid, 50 octopus, 30 mussels and 100 freshwater fish were examined microbiologically for the presence of microorganisms potentially pathogenic. All samples were examined following standard microbiological procedures. The isolated microorganisms were: Aeromonas hydrophilia (38,93%), Klebsiella ozonae (1,40%), Escherichia coli (14,87%), Yersinia enterocolitica (0,40%), Hafnia alvei (0,36.6%), Enterobacter agglomerans (0,42%), Citrobacter freundii (0,46%), Proteus vulgaris (15,80%), Proteus mirabilis (7,82%), Morganella morganii (0,30%), Pseudomonas fluorescens (0,34%), Pseudomonas putida (0,6%), Plesiomonas shigelloides (0,4%), Listeria innocua (1,3.3%), Vibrio parahaemolyticus (0,2%), Clostridium perfringens (0,1%), Staphylococcus aureus (0,80%) and Candida quillermondi (0,1%), Candida albicans (0,1%), Penicillium oxalicum (0,1%) and Penicillium italicum (0,12%). [source] Chemical Characterization of Liver Lipid and Protein from Cold-Water Fish SpeciesJOURNAL OF FOOD SCIENCE, Issue 6 2006Peter J. Bechtel ABSTRACT:, The largest US harvests of marine fish for human consumption are from Alaska waters. Livers from these fish are combined with other fish offal and made into fish meal and oil or discarded. The purpose of this study was to characterize liver lipids and proteins from important commercial species including walleye pollock (WP), pink salmon (PS), Pacific halibut (PH), flat head sole (FS), and spiny head rock fish (RF), and underutilized species including arrow tooth flounder (AF) and big mouth sculpin (BS). Liver lipid content ranged from 50.3% in WP to 3.3% in PS. Protein content ranged from 7.7% in WP to 18.4% in BS. PS livers had the highest content of ,-3 fatty acids at 336 mg/g of oil and AF had the lowest content at 110 mg/g of oil. There were significant differences in the content of 9 amino acids with methionine and lysine values ranging from 2.66% to 3.43% and 7.19% to 9.45% of the total amino acids, respectively. Protein from the cold water marine fish livers was of high quality and the oils contained substantial quantities of ,-3 fatty acids. Fish livers had distinct chemical properties and can be used for the development of unique food ingredients. [source] Relating the ontogeny of functional morphology and prey selection with larval mortality in Amphiprion frenatusJOURNAL OF MORPHOLOGY, Issue 6 2010Justin Anto Abstract Survival during the pelagic larval phase of marine fish is highly variable and is subject to numerous factors. A sharp decline in the number of surviving larvae usually occurs during the transition from endogenous to exogenous feeding known as the first feeding stage in fish larvae. The present study was designed to evaluate the link between functional morphology and prey selection in an attempt to understand how the relationship influences mortality of a marine fish larva, Amphiprion frenatus, through ontogeny. Larvae were reared from hatch to 14 days post hatch (DPH) with one of four diets [rotifers and newly hatched Artemia sp. nauplii (RA); rotifers and wild plankton (RP); rotifers, wild plankton, and newly hatched Artemia nauplii (RPA); wild plankton and newly hatched Artemia nauplii (PA)]. Survival did not differ among diets. Larvae from all diets experienced mass mortality from 1 to 5 DPH followed by decreased mortality from 6 to 14 DPH; individuals fed RA were the exception, exhibiting continuous mortality from 6 to 14 DPH. Larvae consumed progressively larger prey with growth and age, likely due to age related increase in gape. During the mass mortality event, larvae selected small prey items and exhibited few ossified elements. Cessation of mass mortality coincided with consumption of large prey and ossification of key elements of the feeding apparatus. Mass mortality did not appear to be solely influenced by inability to establish first feeding. We hypothesize the interaction of reduced feeding capacities (i.e., complexity of the feeding apparatus) and larval physiology such as digestion or absorption efficiency contributed to the mortality event during the first feeding period. J. Morphol., 2010. © 2010 Wiley-Liss, Inc. [source] Gonadal morphogenesis and sex differentiation in intraovarian embryos of the viviparous fish Zoarces viviparus (Teleostei, Perciformes, Zoarcidae): A histological and ultrastructural studyJOURNAL OF MORPHOLOGY, Issue 9 2006Tina H. Rasmussen Abstract It is essential to know the timing and process of normal gonadal differentiation and development in the specific species being investigated in order to evaluate the effect of exposure to endocrine-disrupting chemicals on these processes. In the present study gonadal sex differentiation and development were investigated in embryos of a viviparous species of marine fish, the eelpout, Zoarces viviparus, during their intraovarian development (early September to January) using light and electron microscopy. In both sexes of the embryos at the time of hatching (September 20) the initially undifferentiated paired bilobed gonad contains primordial germ cells. In the female embryos, ovarian differentiation, initiated 14 days posthatch (dph), is characterized by the initial formation of the endoovarian cavity of the single ovary as well as by the presence of some early meiotic oocytes in a chromatin-nucleolus stage. By 30 dph, the endoovarian cavity has formed. By 44 dph and onward, the ovary and the oocytes grow in size and at 134 dph, just prior to birth, the majority of the oocytes are at the perinucleolar stage of primary growth and definitive follicles have formed. In the presumptive bilobed testis of the male embryos, the germ cells (spermatogonia), in contrast to the germ cells of the ovary, remain quiescent and do not enter meiosis during intraovarian development. However, other structural (somatic) changes, such as the initial formation of the sperm duct (30 dph), the presence of blood vessels in the stromal areas of the testis (30 dph), and the appearance of developing testicular lobules (102 dph), indicate testicular differentiation. Ultrastructually, the features of the primordial germ cells, oogonia, and spermatogonia are similar, including nuage, mitochondria, endoplasmic reticulum, and Golgi complexes. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Identification and pathogenicity of Vibrio ponticus affecting cultured Japanese sea bass, Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes)LETTERS IN APPLIED MICROBIOLOGY, Issue 1 2007Z.Y. Xie Abstract Aims:, To rapidly determine the causative agent of mass death in Lateolabrax japonicus in Zhelin Bay of Guangdong Province in China in April 2004. Methods and Results:, Thirty-six strains, numbered sequentially from RP01 to RP36, were isolated from six diseased fish. All of the strains were identified as being of the same vibrio species according to the results of universal primer PCR combined with DGGE (UPPCR-DGGE). RP30 was one of these strains that was randomly selected and analysed by using a morphological, physiological and biochemical plate, Biolog GN2 Microplate System and API 20E system. Furthermore, RP30, 16S rDNA was sequenced and aligned in Genbank. Its virulence to Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was also tested. RP30 is most closely related to four Vibrio ponticus strains (99·3% similarity). LD50s were 2·5 (×103 CFU per fish for intraperitoneal inoculation (IP) and 3·2 (×103 CFU per fish for intramuscular inoculation (IM), respectively. Conclusions:, The investigated pathogenic agent of Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was V. ponticus. Significance and Impact of the Study:, UPPCR-DGGE is very helpful in epidemiologic investigation. Interestingly, this is the first report that V. ponticus infects cultured marine fish. DGGE was likewise first introduced to epidemiologic investigation of fish disease. [source] Vibrio harveyi: a significant pathogen of marine vertebrates and invertebratesLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2006B. Austin Abstract Vibrio harveyi, which now includes Vibrio carchariae as a junior synonym, is a serious pathogen of marine fish and invertebrates, particularly penaeid shrimp. In fish, the diseases include vasculitis, gastro-enteritis and eye lesions. With shrimp, the pathogen is associated with luminous vibriosis and Bolitas negricans. Yet, the pathogenicity mechanisms are imprecisely understood, with likely mechanisms involving the ability to attach and form biofilms, quorum sensing, various extracellular products including proteases and haemolysins, lipopolysaccharide, and interaction with bacteriophage and bacteriocin-like substances. [source] Use of chemical tracers to assess diet and persistent organic pollutants in Antarctic Type C killer whalesMARINE MAMMAL SCIENCE, Issue 3 2008Margaret M. Krahn Abstract Measuring chemical tracers in tissues of marine predators provides insight into the prey consumed and the predator's contaminant exposure. In this study, samples from Type C killer whales (Orcinus orca) biopsied in Antarctica were analyzed for chemical tracers (i.e., stable isotopes of carbon and nitrogen, fatty acids, and persistent organic pollutants [POPs]). Profiles of these individual tracers were very different from those of killer whale populations that have been studied in the eastern North and eastern Tropical Pacific. For example, ,13C and ,15N stable isotope values and most POP concentrations were significantly lower in the Antarctic population. In addition, multivariate statistical analyses of both fatty acid and POP profiles found distinctly different patterns for Antarctic Type C whales compared to those from whales in the other populations. Similar assays were conducted on four species of Antarctic marine fish considered potential prey for Type C killer whales. Results were consistent with a diet of fish for Type C whales, but other species (e.g., low trophic-level marine mammals or penguins) could not be eliminated as supplemental prey. [source] Protection of red sea bream Pagrus major against red sea bream iridovirus infection by vaccination with a recombinant viral proteinMICROBIOLOGY AND IMMUNOLOGY, Issue 3 2010Hajime Shimmoto ABSTRACT Megalocytivirus infections cause serious mass mortality in marine fish in East and Southeast Asian countries. In this study the immunogenicity of crude subunit vaccines against infection by the Megalocytivirus RSIV was investigated. Three capsid proteins, 18R, 351R and a major capsid protein, were selected for use as crude subunit vaccines. High homology among Megalocytivirus types was found in the initial sequence examined, the 351R region. Red sea bream (Pagrus major) juveniles were vaccinated by intraperitoneal injection of recombinant formalin-killed Escherichia coli cells expressing these three capsid proteins. After challenge infection with RSIV, fish vaccinated with the 351R-recombinant bacteria showed significantly greater survival than those vaccinated with control bacteria. The 351R protein was co-expressed with GAPDH from the bacterium Edwardsiella tarda in E. coli; this also protected against viral challenge. A remarkable accumulation of RSIV was observed in the blood of vaccinated fish, with less accumulation in the gills and spleen tissues. Thus, the 351R-GAPDH fusion protein is a potential vaccine against Megalocytivirus infection in red sea bream. [source] Phylogeography of the common goby, Pomatoschistus microps, with particular emphasis on the colonization of the Mediterranean and the North SeaMOLECULAR ECOLOGY, Issue 2 2004E. S. Gysels Abstract The phylogeographical patterns of a small marine fish, the common goby, Pomatoschistus microps, were assessed at 12 sites along the northeastern Atlantic coasts and the western Mediterranean Sea. A combination of two genetic markers was employed: cellulose acetate allozyme electrophoresis (CAGE) and sequence analysis of a 289 bp fragment of the mitochondrial locus cytochrome b. Both markers were congruent in revealing significant differences between samples (global FST = 0.247 for the allozymes and ,ST = 0.437 for the mitochondrial DNA data) and a pattern of isolation-by-distance. Phylogeographical analyses yielded a shallow branching structure with four groups. Three of those were confined to the Atlantic basin and showed a star-like pattern. The fourth group contained a central haplotype occurring at the edges of the species' distribution, accompanied by a few more rare variants, which were restricted to the Mediterranean Sea. A genetic break was observed around the British Isles, with distinct haplotypes dominating at either side of the English Channel. A significantly negative correlation between the degree of genetic diversity and latitude was recorded both for mitochondrial DNA (mtDNA) and allozymes in the Atlantic basin. Gene flow analysis suggested that recolonization of the North Sea and the coasts of western Scotland and Ireland may have taken place from a glacial refugium in the Southern Bight of the North Sea. These results are discussed in the perspective of possible postglacial migration routes of marine fish along the northeastern Atlantic coasts. [source] Isolation and characterization of microsatellite loci in the deep-sea marine fish, the roundnose grenadier (Coryphaenoides rupestris)MOLECULAR ECOLOGY RESOURCES, Issue 5 2008HALVOR KNUTSEN Abstract We developed polymerase chain reaction primers for eight dinucleotide microsatellite loci in the marine deep sea fish, roundnose grenadier (Coryphaenoides rupestris). All markers were obtained from a partial genomic DNA library, and characterized in 90 unrelated individuals from one putative population sampled on the Mid-Atlantic Ridge. The number of alleles ranged from two to 61 with an average of 21 per locus. The observed heterozygosity levels ranged from 0.301 to 0.987 with an average of 0.672. Several of the markers amplified multiple alleles from either the Atlantic cod (Gadus morhua) or the deep-sea fish roughhead grenadier (Macrourus berglax). [source] Presence of Rhodopsin and Porphyropsin in the Eyes of 164 Fishes, Representing Marine, Diadromous, Coastal and Freshwater Species,A Qualitative and Comparative Study,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2008Mina Toyama There are two types of visual pigments in fish eyes; most marine fishes have rhodopsin, while most freshwater fishes have porphyropsin. The biochemical basis for this dichotomy is the nature of the chromophores, retinal (A1) and 3-dehydroretinal (A2), each of which is bound by an opsin. In order to study the regional distribution of these visual pigments, we performed a new survey of the visual pigment chromophores in the eyes of many species of fish. Fish eyes from 164 species were used to examine their chromophores by high-performance liquid chromatography,44 species of freshwater fish, 20 of peripheral freshwater fish (coastal species), 10 of diadromous fish and 90 of seawater fish (marine species) were studied. The eyes of freshwater fish, limb freshwater fish and diadromous fish had both A1 and A2 chromophores, whereas those of marine fish possessed only A1 chromophores. Our results are similar to those of previous studies; however, we made a new finding that fish which live in freshwater possessed A1 if living near the sea and A2 if living far from the sea if they possessed only one type of chromophore. [source] Stable isotopic evidence for diet at the Imperial Roman coastal site of Velia (1st and 2nd Centuries AD) in Southern ItalyAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Oliver E. Craig Abstract Here we report on a stable isotope palaeodietary study of a Imperial Roman population interred near the port of Velia in Southern Italy during the 1st and 2nd centuries AD. Carbon and nitrogen stable isotope analyses were performed on collagen extracted from 117 adult humans as well as a range of fauna to reconstruct individual dietary histories. For the majority of individuals, we found that stable isotope data were consistent with a diet high in cereals, with relatively modest contributions of meat and only minor contributions of marine fish. However, substantial isotopic variation was found within the population, indicating that diets were not uniform. We suggest that a number of individuals, mainly but not exclusively males, had greater access to marine resources, especially high trophic level fish. However, the observed dietary variation did not correlate with burial type, number of grave goods, nor age at death. Also, individuals buried at the necropolis at Velia ate much less fish overall compared with the contemporaneous population from the necropolis of Portus at Isola Sacra, located on the coast close to Rome. Marine and riverine transport and commerce dominated the economy of Portus, and its people were in a position to supplement their own stocks of fish with imported goods in transit to Rome, whereas at Velia marine exploitation existed side-by-side with land-based economic activities. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Comparison of Small Subunit Ribosomal RNA Gene and Internal Transcribed Spacer Sequences Among Isolates of the Intranuclear Microsporidian Nucleospora salmonisTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 4 2000STEPHANE J. GRESOVIAC ABSTRACT. Nucleospora salmonis is an intranuclear microsporidian associated with a proliferative disorder of the lymphoid cells of captive salmonid fish in the northwestern and northeastern regions of North America, in France, and in Chile. Newer diagnostic approaches have used the polymerase chain reaction (PCR) to detect the parasite in fish tissues. The target sequences for these assays lie in the small subunit ribosomal RNA (ssu rRNA) gene or internal transcribed spacer (ITS) as determined from N. salmonis from chinook salmon (Oncorhynchus tshawytscha) from the Pacific Northwest of North America. The lack of sequence data on parasites from diverse geographic origins and hosts led us to compare several isolates of N. salmonis. There was a high degree of similarity in the ssu rDNA sequences (> 98%) among all the isolates of N. salmonis examined, regardless of host or geographic origin. The greatest sequence differences were found between isolates from the Pacific regions of America. Isolates from Chile shared sequences with one or both geographic groups from North America. A similar distribution of sequence types was observed when ITS-1 sequences of selected isolates were analyzed. Sequence data from two N. salmonis -like isolates from marine non-salmonid fish showed one closely related and the second less closely related to N. salmonis isolates from salmonid fish. These results provide evidence for a homogeneous group of aquatic members of the genus Nucleospora found among salmonid fish (N. salmonis) that can be detected using diagnostic PCR assays with ssu rDNA target sequences. The presence of parasites related to N. salmonis among marine fish suggests a potentially broad host and geographic distribution of members of the family Enterocytozoonidae. [source] A method to determine protein digestibility of microdiets for larval and early juvenile fishAQUACULTURE NUTRITION, Issue 6 2009J.M. HANSEN Abstract A method to evaluate protein quality using in vivo methods was developed for larval fish. FluoSpheres® fluorescent microspheres (10 ,m) were incorporated into two test diets, our standard zein microdiet (ZMD) and a microdiet with identical ingredients except for the replacement of high quality fish meal with the same product cooked for 24 h at 80 °C (ZMD-CF). Several trials were performed to design a reliable method to test digestibility using FluoSpheres® as a marker. The developed in vivo technique was tested on 35 days posthatch (dph) larval Atlantic cod (Gadus morhua L.) and two tropical fish species in the early juvenile stage. The method took into account loss of total protein to the faecal pellet and water column. Apparent digestibility of protein in larval cod fed ZMD was significantly higher than that of larvae fed ZMD-CF (P < 0.05). A growth study to validate differences between the two diets showed significant differences in growth and survival of larvae fed ZMD versus ZMD-CF (P < 0.05). Further validation of our results was indicated through the use of a pH-stat method using enzymes extracted from 35 dph larval cod guts. This novel technique will be advantageous for researchers to evaluate feed ingredients for larval marine fish and is adaptable to many different areas of larval fish nutrition. [source] Fatty acid requirements in ontogeny of marine and freshwater fishAQUACULTURE RESEARCH, Issue 5 2010Douglas R. Tocher Abstract Essential fatty acid (EFA) requirements vary qualitatively and quantitatively with both species and during ontogeny of fish, with early developmental stages and broodstock being critical periods. Environment and/or trophic level are major factors, with freshwater/diadromous species generally requiring C18 polyunsaturated fatty acids (PUFA) whereas marine fish have a strict requirement for long-chain PUFA, eicosapentaenoic, docosahexaenoic and arachidonic acids. Other than marine fish larvae, defining precise quantitative or semi-quantitative EFA requirements in fish have received less attention in recent years. However, the changes to feed formulations being forced upon the aquaculture industry by the pressing need for sustainable development, namely the replacement of marine fish meal and oils with plant-derived products, have reintroduced EFA into the research agenda. It is particularly important to note that the physiological requirements of the fish to prevent deficiency pathologies and produce optimal growth may not parallel the requirements for maintaining nutritional quality. For instance, salmonids can be successfully cultured on vegetable oils devoid of long-chain n-3 PUFA but not without potentially compromising their health benefits to the human consumer. Solving this problem will require detailed knowledge of the biochemical and molecular basis of EFA requirements and metabolism. [source] | ||||||||||||||||