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David L Taylor - One of the best experts on this subject based on the ideXlab platform.
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predation on post settlement winter flounder Pseudopleuronectes americanus by sand shrimp crangon septemspinosa in nw atlantic estuaries
Marine Ecology Progress Series, 2005Co-Authors: David L TaylorAbstract:Assessing predation risk is necessary to evaluate the functional significance of estuaries as critical nursery habitats for juvenile fishes. The objective of this study was to quantify rates of sand shrimp Crangon septemspinosa predation on post-settlement winter flounder Pseudopleuronectes americanus in 3 NW Atlantic estuaries: Narragansett Bay (Rhode Island), Niantic River (Connecticut), and Navesink River/Sandy Hook Bay (New Jersey). Sand shrimp were collected from designated study sites in late spring and summer (2001 and 2002), and their stomach contents were analyzed with immunological assays to detect the presence of juvenile winter flounder in the diet. The results indicate that sand shrimp are possible sources of intense predator-induced mortality for newly settled winter flounder. There was a direct relationship between the incidence of winter flounder in shrimp stomachs and the body size and density of shrimp. The importance of sand shrimp as a mortality fac- tor for winter flounder in the Navesink River/Sandy Hook Bay was minimal due to the low abundance of large shrimp (≥30 mm total length). Conversely, in Narragansett Bay and the Niantic River preda- tion rates were high because of the presence of large shrimp during peak winter flounder settlement periods (May to early June), when the flatfish are small in size and vulnerable to predation. Thus, sand shrimp predation rates on winter flounder depend on the relative spatial and temporal overlap between the settlement of flounder to the benthos and the movement patterns of large shrimp that migrate into shallow estuaries to reproduce and feed.
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effect of temperature on the functional response and foraging behavior of the sand shrimp crangon septemspinosa preying on juvenile winter flounder Pseudopleuronectes americanus
Marine Ecology Progress Series, 2003Co-Authors: David L Taylor, Jeremy S CollieAbstract:Predator-prey dynamics between the sand shrimp Crangon septemspinosa and juvenile winter flounder Pseudopleuronectes americanus were examined in laboratory experiments to assess the joint effects of varying prey density and temperature on shrimp foraging behavior and flounder mortality. The functional response of shrimp to 6 densities of flounder was determined at 2 tempera- tures (10 and 16°C). The behavioral mechanisms underlying the shrimp's functional response were quantified with visual observations and compared to the foraging parameters predicted by continu- ous-time functional response models. Shrimp consumption rates increased significantly with increas- ing flounder density, irrespective of water temperature. At low flounder densities, however, signifi- cantly more flounder were consumed at 16°C than at 10°C. Analysis of proportional mortality of flounder across prey density and general functional response models revealed a sigmoidal, Type III functional response at 10°C, and a hyperbolic, Type II functional response at 16°C. Model parameter estimates and visual observations of shrimp foraging behavior suggest that the variable functional responses at different temperatures are the result of cold temperatures decreasing predator activity at low flounder densities, and conversely, shrimp maintaining high attack rates at low flounder densities when exposed to warm temperatures. These findings indicate that shrimp are capable of driving flounder populations to local extinction during warm water conditions. The recent warming trend experienced in northwest Atlantic estuaries, and its impact on trophic dynamics, may therefore explain the failure of the winter flounder stocks to recover in these areas.
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size dependent predation on post settlement winter flounder Pseudopleuronectes americanus by sand shrimp crangon septemspinosa
Marine Ecology Progress Series, 2003Co-Authors: David L TaylorAbstract:Juvenile flatfish that are large-at-age are assumed to have a survival advantage because of a reduction in predator-induced mortality (bigger-is-better hypothesis), but this general- ization is largely unsubstantiated in fisheries research. This study examined size-dependent preda- tion on post-settlement winter flounder Pseudopleuronectes americanus by the sand shrimp Crangon septemspinosa, and the interactive effects of flounder density and water temperature on the preda- tor-prey interaction. Shrimp were visually observed foraging on flounder, and the major elements of the 'predation sequence' were quantified, from which the susceptibility and gross vulnerability of flounder were estimated. Flounder susceptibility generally decreased with increasing fish size until a complete refuge from shrimp predation was attained at sizes > 25 mm total length (TL). The gross vulnerability of flounder to shrimp predation was dome-shaped when analyzed graphically with respect to prey size. At the extremes of the vulnerability response curve, small flounder (8 to 12 mm TL) benefited from a decreased rate of encounters with shrimp predators, whereas large flounder (18 to 22 mm TL) profited from superior escape abilities and prolonged predator handling time once attacked and captured. Conversely, intermediate-sized flounder (13 to 17 mm TL) suffered the highest rates of mortality, and this was accentuated with increasing temperature and decreasing flounder density. Intermediate-sized flounder (17 mm TL) were the most energetically profitable for shrimp. Below this size, net energy intake of shrimp decreased because of the lower caloric content of smaller flounder. Above this size, the increased metabolic demands associated with foraging on large flounder resulted in a decrease in shrimp net-energy gain. Moreover, shrimp feeding on low densities of flounder suffered a net loss in energy intake, thus possibly explaining the observed density-dependent predation of crangonid species feeding on flatfish. Results from this study chal- lenge the applicability of the bigger-is-better hypothesis to this specific predator-prey interaction.
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a temperature and size dependent model of sand shrimp crangon septemspinosa predation on juvenile winter flounder Pseudopleuronectes americanus
Canadian Journal of Fisheries and Aquatic Sciences, 2003Co-Authors: David L Taylor, Jeremy S CollieAbstract:We investigated the temperature-mediated vulnerability of postsettled winter flounder (Pseudopleuronectes americanus) to sand shrimp (Crangon septemspinosa) predation. Small increases in flounder growth rates substantially decreased predator-induced mortality. Recent warming trends in Northwest Atlantic estuaries can increase flounder survival by accelerating growth and minimizing the duration during which juveniles are susceptible to size-dependent predation. Extreme temperature increases, however, depress growth because a disproportionate amount of energy is devoted to increased metabolism, leaving less for somatic development. Flounder survival is also reduced during warm years because of intensified shrimp predation. Moreover, interannual variations in temperature affect the relative timing of shrimp migration and flounder settlement, thus controlling the spatial and temporal overlap between predator and prey. Predicted flounder abundance and survival were statistically unrelated to observed flounder ...
Audet Céline - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic boat noise reduces feeding success in winter flounder larvae (Pseudopleuronectes americanus)
'Springer Science and Business Media LLC', 2020Co-Authors: Gendron, Gilberte Isabelle Marie, Tremblay Réjean, Jolivet Aurélie, Olivier Frédéric, Chauvaud Laurent, Winkler Gesche, Audet CélineAbstract:The aim of this study was to explore an emerging discipline addressing the impact of anthropogenic noise on larval stages of marine organisms. We assessed the influence of boat noise on the feeding behaviour of the pelagic larvae of winter flounder (Pseudopleuronectes americanus, Walbaum, 1792). The hypothesis was that boat noise influences the feeding behaviour of P. americanus flounder larvae independently of prey density. Aquaria containing P. americanus larvae were placed in water baths in which boat noise was diffused for the “noise” treatment and compared to control aquaria with no sound emissions. Larvae were filmed using cameras placed above the aquaria and their behaviour was recorded. Larvae exposed to anthropogenic noise displayed significantly fewer hunting events than controls, and their stomach volumes were significantly smaller. This noise effect was the same at all prey densities used, suggesting that larval feeding behaviour is negatively impaired by anthropogenic noise. Keywords : Feeding behaviour ; Winter flounder ; Larvae ; Anthropogenic noise ; Vessel noise
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Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectes americanus)
NRC Research Press (a division of Canadian Science Publishing), 2018Co-Authors: Bélanger Michel, Tremblay Réjean, Turcotte François, Lambert Yvan, Litvak M. K., Audet CélineAbstract:Metamorphosis is a critical developmental stage that presents particular challenges in fish aquaculture. The sharp increase in mortality that accompanies this transformation has often been attributed to nutritional deficiencies. Providing live feed (rotifers [Brachionus plicatilis (MĂźller, 1786)], Artemia [Artemia salina (L., 1758)]) during the larval stages is costly and labour-intensive, which explains why much effort has been put on early weaning. However, previous observations in winter flounder (Pseudopleuronectes americanus (Walbaum, 1792)) indicate that juveniles weaned after settlement had better survival than those weaned at the larval stage. In this study, we tested whether late weaning (at settlement [W0], and groups maintained on co-feeding for one [W1], two [W2], or three [W3] months following settlement) could improve juvenile survival and lipid composition. Our results demonstrated that maintaining co-feeding beyond the larval stage was essential for post-settlement survival. Juveniles co-fed until 90 days after settlement were 32.5% heavier. Analyses of fatty acids trophic markers suggested that juveniles preferentially fed on enriched rotifers rather than inert food. No pigmentation or fin erosion problems were observed in any of the weaning treatments, which indicates good rearing conditions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectes americanus)
'Canadian Science Publishing', 2018Co-Authors: Bélanger Michel, Tremblay Réjean, Turcotte François, Lambert Yvan, Litvak, Matthew Kenneth, Audet CélineAbstract:La métamorphose est une étape critique du développement qui présente des défis particuliers en aquaculture. La forte hausse de mortalité associée à cette étape a souvent été attribuée à des carences nutritionnelles. Fournir de la nourriture vivante (le rotifère Brachionus plicatilis Müller, 1786 et l’artémie Artemia salina (Linnaeus, 1758)) au cours des premiers stades de vie est coûteux et exige beaucoup d’efforts ce qui explique l’intérêt pour un sevrage rapide. Cependant, des observations précédentes chez les juvéniles de plie rouge (Pseudopleuronectes americanus (Walbaum, 1792)) indiquent que des juvéniles sevrés au moment du passage à l’habitat benthique ont une meilleure survie que ceux sevrés au stade larvaire. Dans cette étude, nous avons vérifié si un sevrage tardif (au moment du passage à la phase benthique (W0) et chez des groupes maintenus en alimentation mixte pour 1 mois (W1), 2 mois (W2), ou 3 mois (W3) suivant le début de la phase benthique) pouvait accroître la survie et améliorer les teneurs en lipides. Nos résultats indiquent que le maintien de l’alimentation mixte au-delà du stade larvaire est nécessaire pour améliorer la survie après le passage à la phase benthique. Les juvéniles nourris d’un régime mixte jusqu’à 90 jours suivant le passage à la phase benthique avaient une masse de 32,5 % plus élevée. L’analyse de marqueurs trophiques parmi les acides gras donne à penser que les juvéniles se nourrissent préférentiellement de rotifères. L’absence de problèmes de pigmentation ou d’érosion de nageoire au cours des différents traitements indique la présence de conditions d’élevage adéquates. -- Mots-clés : plie rouge ; Pseudopleuronectes americanus ; sevrage ; proie vivante ; classes de lipides ; acides gras ; aquaculture
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Effect of sediment, salinity, and velocity on the behavior of juvenile winter flounder (Pseudopleuronectes americanus)
'Springer Science and Business Media LLC', 2018Co-Authors: Provencher Tamara, Tremblay Réjean, Olivier Frédéric, Audet CélineAbstract:Winter flounder (Pseudopleuronectes americanus) is a benthic flatfish that is economically important for recreational and commercial fishing in North America. In the last twenty years, the species has undergone a drastic decline, mainly due to anthropic influence. The goal of this study was to gain knowledge on habitat preferences and behavior of juvenile winter flounder to improve the management of natural stocks and optimize release sites of juveniles produced for stock enhancement. Three abiotic factors (sediment, current, and salinity) potentially influencing the distribution of flatfish species were tested in a recircurlating flume with juvenile winter flounder. Time budgets of observed behaviors including swimming, orientation, and burying capacity were analyzed. Sediment texture was the only factor that significantly influenced the burying behavior of winter flounder juveniles; shear velocity, salinity, and sediment had no effect on the orientation of juveniles. -- Keywords : Winter flounder ; Sediment ; Salinity ; Current ; Swimming behavior
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Effects of algae-enriched rotifers on winter flounder (Pseudopleuronectes americanus) gene expression during metamorphosis
'Springer Science and Business Media LLC', 2014Co-Authors: Vagner Marie, De Montgolfier Benjamin, Tremblay Réjean, Sévigny Jean‑marie, Audet CélineAbstract:International audienceThe aim of this study was to evaluate the effect of a dietary highly unsaturated fatty acid (HUFA) deficiency on winter flounder Pseudopleuronectes americanus metamorphosis by examining the growth and the expression of genes involved in some key metabolic processes: lipid digestion, oxidative stress, and growth. Three groups of fish were fed rotifers enriched with different blends of microalgae providing different HUFA profiles: (1) a diet comprising a mixture of three microalgae, Nannochloropsis oculata, Isochrysis galbana, and Pavlova lutheri (Cocktail diet), which contained a balanced combination of ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA); (2) the N. oculata diet (nanno diet), with a low level of DHA; and (3) the I. galbana diet (Tiso diet), characterized by low levels of EPA and AA. The results indicate that the need for DHA increased from settlement and for EPA and aa from 15 days after settlement. The lower HUFA content in the Tiso and nanno diets did not affect larval development or lipid reserve accumulation. The superoxide dismutase gene expression suggests a reduced oxidative stress in the Cocktail group, and overall results indicate that gh gene expression could be a valuable indicator of development at the molecular level in response to dietary HUFA quality during metamorphosis in winter flounder
Jeremy S Collie - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature on the functional response and foraging behavior of the sand shrimp crangon septemspinosa preying on juvenile winter flounder Pseudopleuronectes americanus
Marine Ecology Progress Series, 2003Co-Authors: David L Taylor, Jeremy S CollieAbstract:Predator-prey dynamics between the sand shrimp Crangon septemspinosa and juvenile winter flounder Pseudopleuronectes americanus were examined in laboratory experiments to assess the joint effects of varying prey density and temperature on shrimp foraging behavior and flounder mortality. The functional response of shrimp to 6 densities of flounder was determined at 2 tempera- tures (10 and 16°C). The behavioral mechanisms underlying the shrimp's functional response were quantified with visual observations and compared to the foraging parameters predicted by continu- ous-time functional response models. Shrimp consumption rates increased significantly with increas- ing flounder density, irrespective of water temperature. At low flounder densities, however, signifi- cantly more flounder were consumed at 16°C than at 10°C. Analysis of proportional mortality of flounder across prey density and general functional response models revealed a sigmoidal, Type III functional response at 10°C, and a hyperbolic, Type II functional response at 16°C. Model parameter estimates and visual observations of shrimp foraging behavior suggest that the variable functional responses at different temperatures are the result of cold temperatures decreasing predator activity at low flounder densities, and conversely, shrimp maintaining high attack rates at low flounder densities when exposed to warm temperatures. These findings indicate that shrimp are capable of driving flounder populations to local extinction during warm water conditions. The recent warming trend experienced in northwest Atlantic estuaries, and its impact on trophic dynamics, may therefore explain the failure of the winter flounder stocks to recover in these areas.
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a temperature and size dependent model of sand shrimp crangon septemspinosa predation on juvenile winter flounder Pseudopleuronectes americanus
Canadian Journal of Fisheries and Aquatic Sciences, 2003Co-Authors: David L Taylor, Jeremy S CollieAbstract:We investigated the temperature-mediated vulnerability of postsettled winter flounder (Pseudopleuronectes americanus) to sand shrimp (Crangon septemspinosa) predation. Small increases in flounder growth rates substantially decreased predator-induced mortality. Recent warming trends in Northwest Atlantic estuaries can increase flounder survival by accelerating growth and minimizing the duration during which juveniles are susceptible to size-dependent predation. Extreme temperature increases, however, depress growth because a disproportionate amount of energy is devoted to increased metabolism, leaving less for somatic development. Flounder survival is also reduced during warm years because of intensified shrimp predation. Moreover, interannual variations in temperature affect the relative timing of shrimp migration and flounder settlement, thus controlling the spatial and temporal overlap between predator and prey. Predicted flounder abundance and survival were statistically unrelated to observed flounder ...
Taylor, David L. - One of the best experts on this subject based on the ideXlab platform.
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Piscivory in age-0 summer flounder Paralichthys dentatus with a focus on predator-induced mortality of post-settlement winter flounder Pseudopleuronectes americanus
'Inter-Research Science Center', 2019Co-Authors: Taylor, David L., Cribari, Kelly J., Scro AbigailAbstract:We examined the piscivorous diet of age-0 summer flounder Paralichthys dentatus in southern New England tidal rivers, with a focus on their predatory impact on post-settlement winter flounder Pseudopleuronectes americanus. The population density, size-structure, and growth of age-0 summer flounder and winter flounder were evaluated in the Seekonk and Taunton Rivers (Rhode Island and Massachusetts, USA, respectively) between May and August/September 2009 through 2015. For a subsample of summer flounder collected during this time (20−181 mm total length, TL; n = 743), diet was assessed using direct visual analysis and PCR-based assays that detect winter flounder mitochondrial DNA within predator stomach contents. Summer flounder were generalist piscivores consuming 8 distinct fish prey taxa from both epibenthic and pelagic guilds. The most frequently observed fishes in the diet of summer flounder were age-0 winter flounder and herring (Clupeidae) with frequencies of occurrence, %F, of 2.6 and 2.0 %, respectively, and overall %F of fish equal to 13.6 %. Fish were absent in the stomachs of summer flounder \u3c 44 mm TL, beyond which piscivory increased significantly with increasing predator size. Summer flounder 50−153 mm TL preyed on winter flounder ranging from 19−54 mm TL, resulting in predator-to-prey size ratios of 2.2−3.6 (mean ± SD = 2.8 ± 0.3). Incidences of summer flounder predation on winter flounder were positively related to body size ratios, and this relationship was attributed to the enlarged mouth gape and improved prey capture abilities of larger predators. Summer flounder predation on fishes, including winter flounder, also demonstrated significant spatiotemporal variability, reflecting riverine and seasonal differences in flounder population size structure and dynamics in prey composition and availability. Deterministic model simulations estimated that age-0 summer flounder accoun
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Feeding habits and dietary overlap of age-0 winter flounder (Pseudopleuronectes americanus) and summer flounder (Paralichthys dentatus) in southern New England tidal rivers
DOCS@RWU, 2017Co-Authors: Taylor, David L., Gervasi, Carissa L.Abstract:Age-0 winter flounder (Pseudopleuronectes americanus; 20-90 mm in total length [TL]) and summer flounder (Paralichthys dentatus; 19-172 mm TL) were collected from the Seekonk and Taunton Rivers (in Rhode Island and Massachusetts, respectively) from May through September during 2009-2015, and stomach content analysis was used to assess diet composition and resource overlap for these species. Winter and summer flounder underwent ontogenetic dietary shifts. Winter flounder \u3c40 mm TL predominantly fed on copepods, transitioning to amphipods, isopods, and bivalves with increasing size. Polychaetes also were consumed frequently by winter flounder, irrespective of size. The principal prey of summer flounder \u3c60 mm TL were mysid shrimp and copepods, whereas sand shrimp (Crangon septemspinosa), amphipods, and fish were the dominant prey of larger conspecifics. There was minimal dietary overlap for the flounder species when comparisons were made independent of body size, indicating food niche segregation. For winter and summer flounder of equivalent sizes, however, dietary overlap was inversely related to TL. Moderate to high resource overlap occurred for small winter and summer flounder (\u3c40 mm TL) and was attributed to their mutual reliance on copepods and amphipods. Despite evidence of dietary overlap, it is unlikely that shared prey resources were diminished enough to negatively affect either flounder species
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Juvenile Winter Flounder (Pseudopleuronectes americanus) and Summer Flounder (Paralichthys dentatus) Utilization of Southern New England Nurseries: Comparisons Among Estuarine, Tidal River, and Coastal Lagoon Shallow-Water Habitats
DOCS@RWU, 2016Co-Authors: Taylor, David L., Gervasi, Carissa L., Mcnamee Jason, Lake John, Palance, Danial G.Abstract:This study evaluated the relative importance of the Narragansett Bay estuary (RI and MA, USA), and associated tidal rivers and coastal lagoons, as nurseries for juvenile winter flounder, Pseudopleuronectes americanus, and summer flounder, Paralichthys dentatus. Winter flounder (WF) and summer flounder (SF) abundance and growth were measured from May to October (2009–2013) and served as indicators for the use and quality of shallow-water habitats (water depth \u3c1.5–3.0 m). These bioindicators were then analyzed with respect to physiochemical conditions to determine the mechanisms underlying intraspecific habitat selection. WF and SF abundances were greatest in late May and June (maximum monthly mean = 4.9 and 0.55 flounder/m2 for WF and SF, respectively) and were significantly higher in the tidal rivers relative to the bay and lagoons. Habitat-related patterns in WF and SF abundance were primarily governed by their preferences for oligohaline (0.1–5 ppt) and mesohaline (6–18 ppt) waters, but also their respective avoidance of hypoxic conditions (\u3c4 mg DO/L) and warm water temperatures (\u3e25 °C). Flounder habitat usage was also positively related to sediment organic content, which may be due to these substrates having sufficiently high prey densities. WF growth rates (mean = 0.25 ± 0.14 mm/day) were negatively correlated with the abundance of conspecifics, whereas SF growth (mean = 1.39 ± 0.46 mm/day) was positively related to temperature and salinity. Also, contrary to expectations, flounder occupied habitats that offered no ostensible advantage in intraspecific growth rates. WF and SF exposed to low salinities in certain rivers likely experienced increased osmoregulatory costs, thereby reducing energy for somatic growth. Low-salinity habitats, however, may benefit flounder by providing refugia from predation or reduced competition with other estuarine fishes and macroinvertebrates. Examining WF and SF abundance and growth across each species’ broader geographic distribution revealed that southern New England habitats may constitute functionally significant nurseries. These results also indicated that juvenile SF have a geographic range extending further north than previously recognized
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Assessing habitat quality of Mount Hope Bay and Narragansett Bay using growth, RNA:DNA, and feeding habits of caged juvenile Winter Flounder (Pseudopleuronectes americanus Walbaum)
'Humboldt Field Research Institute', 2008Co-Authors: Meng Lesa, Taylor, David L., Serbst Jonathan, Powell J. ChristopherAbstract:Somatic growth rates, RNA:DNA, and feeding habits of juvenile Pseudopleuronectes americanus (Winter Flounder) were used to asses small-scale spatio-temporal variations in the habitat quality of Mount Hope Bay and Narragansett Bay, RI. Three successive caging experiments (14-16 d each) were conducted with flounder (initial size = 25-35 mm total length) in June and July 2003 in shallow water habitats (\u3c1 m) of Spar Island, Common Fence Point, and Hog Island; the first two sites were located in Mount Hope Bay, and the latter in Narragansett Bay. The average growth rate of flounder ranged between 0.51 and 0.95 mm d-1 and was inversely related with increased incidences of hypoxic conditions (i.e., amount of time dissolved oxygen was ≤4.0 mg L -1). RNA:DNA, a surrogate measure of growth and feeding condition, corroborated somatic growth trends, and therefore exhibited similar spatio-temporal variability. In contrast to somatic growth, however, water temperature was the most important factor affecting flounder condition, such that RNA:DNA was inversely related to the amount of time water temperature was \u3e20 °C Benthic core samples indicated that food availability was greatest at Spar Island and was attributable to the numerical dominance of Crepidula fornicata Linnaeus (slipper limpet) during the early summer. Moreover, stomach contents of flounder reflected differences in prey species composition, whereby individuals from Spar Island consumed a higher percentage of molluscs relative to the other sites, where the preferred prey items were harpacticoid copepods and small decapods (primarily brachyuran crabs). Despite the observed discrepancies in feeding habits across sites, the extent of stomach fullness for flounder did not vary spatially (mean fullness = 44-49% across sites). It is concluded that the somatic growth, RNA:DNA, and feeding behavior of juvenile flounder in Mount Hope Bay and Narragansett Bay varies significantly across small spatio-temporal scales in response to changes in dissolved oxygen and thermal conditions
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Predation on winter flounder (Pseudopleuronectes americanus) eggs by the sand shrimp (Crangon septemspinosa)
'Canadian Science Publishing', 2005Co-Authors: Taylor, David L., Danila, Donald J.Abstract:This study estimated rates of sand shrimp (Crangon septemspinosa) predation on winter flounder (Pseudopleuronectes americanus) eggs and examined the effect of temperature on density-dependent mortality of early-stage flounder. In laboratory experiments, shrimp feeding rates on flounder eggs were positively correlated with temperature and shrimp size. Immunological assays of shrimp stomach contents indicated that 7.2% of shrimp collected from the Niantic River (Connecticut) had flounder eggs in their stomachs. Incidence of egg predation was highest in February (20%) and decreased continuously into early April (1.2%). In a deterministic model simulating predator-induced mortality of flounder eggs during a spawning season, shrimp consumed 0.4%-49.7% of the total flounder spawn. Variations in shrimp population abundance and size structure accounted for the greatest variability in egg mortality. Water temperature during the spawning season presumably alters the population dynamics of early-stage flounder. In a long-term survey, the number of yolk-sac flounder larvae in warm years (≥4.3°C) was depressed at high egg densities, indicating strong compensatory processes that increased egg mortality and limited the abundance of larvae. Failure of flounder to produce strong year-classes of larvae during warm years, possibly resulting from altered trophic dynamics, may explain the inability of stocks to recover from previous overexploitation. © 2005 NRC
Tremblay Réjean - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic boat noise reduces feeding success in winter flounder larvae (Pseudopleuronectes americanus)
'Springer Science and Business Media LLC', 2020Co-Authors: Gendron, Gilberte Isabelle Marie, Tremblay Réjean, Jolivet Aurélie, Olivier Frédéric, Chauvaud Laurent, Winkler Gesche, Audet CélineAbstract:The aim of this study was to explore an emerging discipline addressing the impact of anthropogenic noise on larval stages of marine organisms. We assessed the influence of boat noise on the feeding behaviour of the pelagic larvae of winter flounder (Pseudopleuronectes americanus, Walbaum, 1792). The hypothesis was that boat noise influences the feeding behaviour of P. americanus flounder larvae independently of prey density. Aquaria containing P. americanus larvae were placed in water baths in which boat noise was diffused for the “noise” treatment and compared to control aquaria with no sound emissions. Larvae were filmed using cameras placed above the aquaria and their behaviour was recorded. Larvae exposed to anthropogenic noise displayed significantly fewer hunting events than controls, and their stomach volumes were significantly smaller. This noise effect was the same at all prey densities used, suggesting that larval feeding behaviour is negatively impaired by anthropogenic noise. Keywords : Feeding behaviour ; Winter flounder ; Larvae ; Anthropogenic noise ; Vessel noise
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Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectes americanus)
NRC Research Press (a division of Canadian Science Publishing), 2018Co-Authors: Bélanger Michel, Tremblay Réjean, Turcotte François, Lambert Yvan, Litvak M. K., Audet CélineAbstract:Metamorphosis is a critical developmental stage that presents particular challenges in fish aquaculture. The sharp increase in mortality that accompanies this transformation has often been attributed to nutritional deficiencies. Providing live feed (rotifers [Brachionus plicatilis (MĂźller, 1786)], Artemia [Artemia salina (L., 1758)]) during the larval stages is costly and labour-intensive, which explains why much effort has been put on early weaning. However, previous observations in winter flounder (Pseudopleuronectes americanus (Walbaum, 1792)) indicate that juveniles weaned after settlement had better survival than those weaned at the larval stage. In this study, we tested whether late weaning (at settlement [W0], and groups maintained on co-feeding for one [W1], two [W2], or three [W3] months following settlement) could improve juvenile survival and lipid composition. Our results demonstrated that maintaining co-feeding beyond the larval stage was essential for post-settlement survival. Juveniles co-fed until 90 days after settlement were 32.5% heavier. Analyses of fatty acids trophic markers suggested that juveniles preferentially fed on enriched rotifers rather than inert food. No pigmentation or fin erosion problems were observed in any of the weaning treatments, which indicates good rearing conditions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectes americanus)
'Canadian Science Publishing', 2018Co-Authors: Bélanger Michel, Tremblay Réjean, Turcotte François, Lambert Yvan, Litvak, Matthew Kenneth, Audet CélineAbstract:La métamorphose est une étape critique du développement qui présente des défis particuliers en aquaculture. La forte hausse de mortalité associée à cette étape a souvent été attribuée à des carences nutritionnelles. Fournir de la nourriture vivante (le rotifère Brachionus plicatilis Müller, 1786 et l’artémie Artemia salina (Linnaeus, 1758)) au cours des premiers stades de vie est coûteux et exige beaucoup d’efforts ce qui explique l’intérêt pour un sevrage rapide. Cependant, des observations précédentes chez les juvéniles de plie rouge (Pseudopleuronectes americanus (Walbaum, 1792)) indiquent que des juvéniles sevrés au moment du passage à l’habitat benthique ont une meilleure survie que ceux sevrés au stade larvaire. Dans cette étude, nous avons vérifié si un sevrage tardif (au moment du passage à la phase benthique (W0) et chez des groupes maintenus en alimentation mixte pour 1 mois (W1), 2 mois (W2), ou 3 mois (W3) suivant le début de la phase benthique) pouvait accroître la survie et améliorer les teneurs en lipides. Nos résultats indiquent que le maintien de l’alimentation mixte au-delà du stade larvaire est nécessaire pour améliorer la survie après le passage à la phase benthique. Les juvéniles nourris d’un régime mixte jusqu’à 90 jours suivant le passage à la phase benthique avaient une masse de 32,5 % plus élevée. L’analyse de marqueurs trophiques parmi les acides gras donne à penser que les juvéniles se nourrissent préférentiellement de rotifères. L’absence de problèmes de pigmentation ou d’érosion de nageoire au cours des différents traitements indique la présence de conditions d’élevage adéquates. -- Mots-clés : plie rouge ; Pseudopleuronectes americanus ; sevrage ; proie vivante ; classes de lipides ; acides gras ; aquaculture
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Effect of sediment, salinity, and velocity on the behavior of juvenile winter flounder (Pseudopleuronectes americanus)
'Springer Science and Business Media LLC', 2018Co-Authors: Provencher Tamara, Tremblay Réjean, Olivier Frédéric, Audet CélineAbstract:Winter flounder (Pseudopleuronectes americanus) is a benthic flatfish that is economically important for recreational and commercial fishing in North America. In the last twenty years, the species has undergone a drastic decline, mainly due to anthropic influence. The goal of this study was to gain knowledge on habitat preferences and behavior of juvenile winter flounder to improve the management of natural stocks and optimize release sites of juveniles produced for stock enhancement. Three abiotic factors (sediment, current, and salinity) potentially influencing the distribution of flatfish species were tested in a recircurlating flume with juvenile winter flounder. Time budgets of observed behaviors including swimming, orientation, and burying capacity were analyzed. Sediment texture was the only factor that significantly influenced the burying behavior of winter flounder juveniles; shear velocity, salinity, and sediment had no effect on the orientation of juveniles. -- Keywords : Winter flounder ; Sediment ; Salinity ; Current ; Swimming behavior
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Effects of algae-enriched rotifers on winter flounder (Pseudopleuronectes americanus) gene expression during metamorphosis
'Springer Science and Business Media LLC', 2014Co-Authors: Vagner Marie, De Montgolfier Benjamin, Tremblay Réjean, Sévigny Jean‑marie, Audet CélineAbstract:International audienceThe aim of this study was to evaluate the effect of a dietary highly unsaturated fatty acid (HUFA) deficiency on winter flounder Pseudopleuronectes americanus metamorphosis by examining the growth and the expression of genes involved in some key metabolic processes: lipid digestion, oxidative stress, and growth. Three groups of fish were fed rotifers enriched with different blends of microalgae providing different HUFA profiles: (1) a diet comprising a mixture of three microalgae, Nannochloropsis oculata, Isochrysis galbana, and Pavlova lutheri (Cocktail diet), which contained a balanced combination of ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA); (2) the N. oculata diet (nanno diet), with a low level of DHA; and (3) the I. galbana diet (Tiso diet), characterized by low levels of EPA and AA. The results indicate that the need for DHA increased from settlement and for EPA and aa from 15 days after settlement. The lower HUFA content in the Tiso and nanno diets did not affect larval development or lipid reserve accumulation. The superoxide dismutase gene expression suggests a reduced oxidative stress in the Cocktail group, and overall results indicate that gh gene expression could be a valuable indicator of development at the molecular level in response to dietary HUFA quality during metamorphosis in winter flounder
