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Tsutomu Hattori - One of the best experts on this subject based on the ideXlab platform.
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movement of juvenile walleye pollock theragra chalcogramma from a spawning Ground to a Nursery Ground along the pacific coast of hokkaido japan
Fisheries Oceanography, 2004Co-Authors: Satoshi Honda, Tatsuki Oshima, Akira Nishimura, Tsutomu HattoriAbstract:The movement of juvenile walleye pollock, Theragra chalcogramma, from the Funka Bay spawning Ground to the Doto Nursery Ground along the Pacific coast of Hokkaido was observed during spring through summer of 2000 and 2001. A positive relationship between the size of the juveniles and the position of the eastern front of their distribution indicated a relationship between the hatching period and the timing of the eastward movement of juveniles toward the Doto area. Based on the bathymetric distribution of juvenile pollock on the continental shelf in Hidaka Bay, the coastal current is suggested to play a role in the easterly movement of juveniles. However, further supporting evidence from physical and biological oceanographic studies is necessary to confirm this hypothesis.
Rachid Amara - One of the best experts on this subject based on the ideXlab platform.
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are estuarine fish opportunistic feeders the case of a low anthropized Nursery Ground the canche estuary france
Estuaries and Coasts, 2015Co-Authors: Jonathan Selleslagh, Rachid AmaraAbstract:Stomach contents of the main fish species (i.e. sprat Sprattus sprattus, sea-bass Dicentrarchus labrax, common goby Pomatoschistus microps and flounder Platichthys flesus) in the Canche Nursery Ground (France) were examined from May 2006 to March 2007 according to food availability (i.e. macrozoobenthos and zooplankton) to analyse diet composition, trophic competition and prey selection. Overall, 44 prey fish species were identified from the 684 stomach contents examined. Fish diet was characterized by a wide diversity of prey, a relatively high feeding activity (vacuity index ranged between 16.9 and 29.0 % according to species) and spatiotemporal changes, except for D. labrax which did not vary between periods or estuarine zones. Copepods Temora longicornis and Euterpina acutifrons were the most important items in the diet of S. sprattus; for D. labrax, the dominant prey was the amphipod Gammarus sp., while Platichthys flesus and Pomatoschistus microps showed a more similar trophic niche (similarity percentage = 39 %) with diets consisting of nematodes and amphipods. Spatiotemporal sharing of trophic resources by fish and high food resources in the Canche estuary was examined, and very limited diet overlap was observed, indicating that competition for food resources was limited. Differences between the available preys and fish diets demonstrated that fish do not select the most abundant food resources. S. sprattus showed a selection for Tachidius sp. and cladocerans; D. labrax for Gammarus sp., Hediste diversicolor and to a lesser extent nematodes and Corophium sp.; Pomatoschistus microps for nematodes and Gammarus sp.; and Platichthys flesus for nematodes, Gammarus sp., H. diversicolor and Corophium sp. It was concluded that the studied fish exhibit a specialist rather than opportunistic feeding strategy.
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Convergent signs of degradation in both the capacity and the quality of an essential fish habitat: state of the Seine estuary (France) flatfish nurseries
Hydrobiologia, 2007Co-Authors: O. Le Pape, Rachid Amara, C. Gilliers, P. Riou, J. Morin, Y. DésaunayAbstract:The Bay of Seine is a potentially important Nursery Ground, especially for flatfish. This area, however, is also strongly anthropogenically influenced. A composite approach was chosen to compare the flatfish Nursery function of the Seine estuary with other coastal and estuarine areas and to determine the impact of anthropogenic disturbances. It emerges that alteration of the Nursery function in the Seine estuary is related to the loss of Nursery habitat and to a lower quality of the residual surfaces. These observations stressed the importance of habitat destruction and decreased quality of remaining habitat for fish stocks renewal.
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0 group flatfish growth conditions on a Nursery Ground bay of canche eastern english channel
Hydrobiologia, 2004Co-Authors: Rachid AmaraAbstract:The settlement and growth conditions of three 0-group flatfish species, sole (Solea solea L.), plaice (Pleuronectes platessa L.) and dab (Limanda limanda L.) in the Bay of Canche, French coast of the Eastern English Channel, were investigated during summer 1997. 0-group dab were the more abundant of the three species (75.4%) followed by plaice (21%) and sole (3.6%). Analyses of fish size distribution indicated that settlement of plaice occurred before sole and dab. Growth of sole was faster than that of plaice, which in turn was faster than that of dab (0.68, 0.43 and 0.33 mm d−1 respectively). Sole differed from plaice and dab by their larger mean length attained at the end of their first summer stay in the Nursery Ground. Growth performances of 0-group sole and plaice were analysed by comparing estimated growth in the field with predicted maximum growth according to temperature-growth rate models from experimental studies of growth with unlimited food supply. The data of this study suggest that plaice growth may have been limited during late summer, whereas sole growth does appear to have been determined only by water temperature.
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seasonal ichthyodiversity and growth patterns of juvenile flatfish on a Nursery Ground in the southern bight of the north sea france
Environmental Biology of Fishes, 2003Co-Authors: Rachid AmaraAbstract:The demersal fish community on a flatfish Nursery Ground, of the Southern Bight of the North Sea, was sampled monthly between May 1998 and 1999. The studied coastal area is a multispecific Nursery area. Although 32 fish species were caught, only nine species had a major influence on the variation in total densities through the year and can be considered as key species. Juvenile sole and plaice exhibited similar seasonal growth patterns with rapid growth during late spring and summer, a growth arrest during autumn and winter and a restart of growth in March. Comparisons of observed growth in length with predicted maximal growth under optimal food conditions suggested that during the summer, growth of 0-group sole and plaice was only determined by prevailing mean water temperature. During autumn and winter, while growth in length of sole followed model predictions, observed length of plaice was less than model predictions, suggesting growth limitation. Analyses of the factors that may be responsible for differences between observed and expected length growth indicated that autumn and winter growth arrest of plaice was not only related to low winter water temperature. It is suggested that for visual feeders such as plaice, the interaction of decreasing food availability and day length during autumn and winter can reduce the access to food resource and therefore feeding success and growth.
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Feeding ecology and growth of O‐group flatfish (sole, dab and plaice) on a Nursery Ground (Southern Bight of the North Sea)
Journal of Fish Biology, 2001Co-Authors: Rachid Amara, Pascal Laffargue, J. M. Dewarumez, C. Maryniak, Françoise Lagardère, C. LuzacAbstract:The food composition of O-group sole Solea solea, dab Limanda limanda and plaice Pleuronectes platessa on a Nursery Ground at Gravelines, France, included 17-25 taxa. Sole (new settlers) fed mainly on harpacticoid copepods and when ≥ 50 mm in size, on polychaetes (Terebellidae). Dab (
S Enriquezbrionnes - One of the best experts on this subject based on the ideXlab platform.
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Nursery Ground age structure and abundance of juvenile squat lobster pleuroncodes monodon on the continental shelf off central chile
Marine Ecology Progress Series, 1995Co-Authors: Victor A Gallardo, B Ernst, M Baltazar, J I Canete, S EnriquezbrionnesAbstract:Newly settled individuals and juveniles of several benthic decapod crustaceans spend their first months or years in Nursery habitats different from those of the adult population. It was unknown if this was the case for the squat lobster Pleuroncodes monodon, an exploited crustacean which inhabits the continental shelf off central Chile, and of which 2 adult populations exist, the larger Achira (35' 10' S to 36' 15' S) and the smaller Biobio (36' 35' S to 36' 50' S). We report here the presence of a large Nursery area of the species, connecting both adult populations; the habitat is dominated by extensive sulphide microbial communities which fluorish at very low oxygen concentrations. We inferred the existence of northerly and southerly migration routes from the Nursery Ground to the adult populations, with juvenile year classes migrating as they advance through age classes. The juvenile population was composed of 2 year classes: 0 yr old (newly settled mdividuals) and 1 yr old juveniles; thus juveniles seemed to spend their first year of life in the Nursery area. Total abundance was estimated as 3290 x lo6 individuals (asymmetric 95 % confidence interval: 2153 to 7039 x lo6), although the above figure is a lower bound because the sampling did not cover the whole Nursery area. We hypothesize that the Biobio adult population is not self-sustaining, but depends on a surplus production of juveniles from the Achira population.
Satoshi Honda - One of the best experts on this subject based on the ideXlab platform.
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movement of juvenile walleye pollock theragra chalcogramma from a spawning Ground to a Nursery Ground along the pacific coast of hokkaido japan
Fisheries Oceanography, 2004Co-Authors: Satoshi Honda, Tatsuki Oshima, Akira Nishimura, Tsutomu HattoriAbstract:The movement of juvenile walleye pollock, Theragra chalcogramma, from the Funka Bay spawning Ground to the Doto Nursery Ground along the Pacific coast of Hokkaido was observed during spring through summer of 2000 and 2001. A positive relationship between the size of the juveniles and the position of the eastern front of their distribution indicated a relationship between the hatching period and the timing of the eastward movement of juveniles toward the Doto area. Based on the bathymetric distribution of juvenile pollock on the continental shelf in Hidaka Bay, the coastal current is suggested to play a role in the easterly movement of juveniles. However, further supporting evidence from physical and biological oceanographic studies is necessary to confirm this hypothesis.
Akira Nishimura - One of the best experts on this subject based on the ideXlab platform.
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Abiotic and biotic factors affecting recruitment variability of walleye pollock (Theragra chalcogramma) off the Pacific coast of Hokkaido, Japan
Fisheries Oceanography, 2013Co-Authors: Tetsuichiro Funamoto, Orio Yamamura, Tokihiro Kono, Tomonori Hamatsu, Akira NishimuraAbstract:Abiotic and biotic factors affecting the recruitment variability of the Japanese Pacific stock (JPS) of walleye pollock (Theragra chalcogramma) were examined using a bivariate regression and multivariate combined model. Of the abiotic variables around Funka Bay (spawning Ground), February sea surface temperature (SST) and wind direction index showed significant bivariate relationships with recruitment. February SST was positively related to recruitment, suggesting that warmer water temperature in February favors JPS recruitment. On the other hand, the relationship between February wind direction index and recruitment predicts high JPS recruitment under predominant northwest winds in February. For the biotic variables in the Doto area (Nursery Ground), significant and negative bivariate relationships with recruitment were observed for catch per unit effort of Kamchatka flounder (Atheresthes evermanni), Pacific cod (Gadus macrocephalus), and walleye pollock, implying an important impact of predation by these Groundfishes on JPS recruitment. The overall model incorporating these abiotic and biotic factors successfully reproduced the variability in JPS recruitment. Temperature and wind conditions around the spawning Ground along with predator condition in the Nursery Ground appear to play a dominant role in the recruitment dynamics of JPS. Based on these results and prior knowledge, we propose a new hypothesis to explain the processes controlling JPS recruitment.
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movement of juvenile walleye pollock theragra chalcogramma from a spawning Ground to a Nursery Ground along the pacific coast of hokkaido japan
Fisheries Oceanography, 2004Co-Authors: Satoshi Honda, Tatsuki Oshima, Akira Nishimura, Tsutomu HattoriAbstract:The movement of juvenile walleye pollock, Theragra chalcogramma, from the Funka Bay spawning Ground to the Doto Nursery Ground along the Pacific coast of Hokkaido was observed during spring through summer of 2000 and 2001. A positive relationship between the size of the juveniles and the position of the eastern front of their distribution indicated a relationship between the hatching period and the timing of the eastward movement of juveniles toward the Doto area. Based on the bathymetric distribution of juvenile pollock on the continental shelf in Hidaka Bay, the coastal current is suggested to play a role in the easterly movement of juveniles. However, further supporting evidence from physical and biological oceanographic studies is necessary to confirm this hypothesis.
