The Experts below are selected from a list of 19491 Experts worldwide ranked by ideXlab platform
Aaron B Carlisle - One of the best experts on this subject based on the ideXlab platform.
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effects of Trophic Ecology and habitat use on maternal transfer of contaminants in four species of young of the year lamniform sharks
Marine Environmental Research, 2013Co-Authors: Kady Lyons, Aaron B Carlisle, Antonella Preti, Christopher G Mull, Mary Ellen Blasius, John Osullivan, Chuck Winkler, Christopher G LoweAbstract:Organic contaminant and total mercury concentrations were compared in four species of lamniform sharks over several age classes to examine bioaccumulation patterns and gain insights into Trophic Ecology. Contaminants found in young of the year (YOY) sharks were assumed to be derived from maternal sources and used as a proxy to investigate factors that influence maternal offloading processes. YOY white (Carcharodon carcharias) and mako (Isurus oxyrinchus) sharks had comparable and significantly higher concentrations of PCBs, DDTs, pesticides, and mercury than YOY thresher (Alopias vulpinus) or salmon (Lamna ditropis) sharks. A significant positive relationship was found between YOY contaminant loads and maternal Trophic position, suggesting that Trophic Ecology is one factor that plays an important role in maternal offloading. Differences in organic contaminant signatures and contaminant concentration magnitudes among species corroborated what is known about species habitat use and may be used to provide insights into the feeding Ecology of these animals.
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Using stable isotope analysis to understand the migration and Trophic Ecology of northeastern Pacific white sharks (Carcharodon carcharias)
PLoS ONE, 2012Co-Authors: Aaron B Carlisle, Christopher R. Perle, Paul E. Kanive, Sora L. Kim, Taylor K. Chapple, Salvador J Jorgensen, Brice X. Semmens, Scot D Anderson, Daniel J Madigan, Barbara A BlockAbstract:The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the Trophic Ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the Trophic Ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.
Daniel J Madigan - One of the best experts on this subject based on the ideXlab platform.
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New insights into the Trophic Ecology of young white sharks (Carcharodon carcharias) in waters off the Baja California Peninsula, Mexico
Marine Biology, 2020Co-Authors: Elena Tamburin, Daniel J Madigan, Fernando R. Elorriaga-verplancken, Colombo Estupiñan-montaño, Alberto Sánchez-gonzález, Mauricio Hoyos Padilla, Michelle Wcisel, Felipe Galván-magañaAbstract:White sharks ( Carcharodon carcharias ) are described as generalist predators, with a demonstrated ontogenetic dietary shift which occurs between subadult and adult life stages. Trophic Ecology studies on white shark have been focused mainly on large and mature individuals, necessitating studies of young white shark Trophic Ecology to better understand their resource use. This study provides new insights into young white shark diet in the North eastern Pacific Ocean using stable isotope analysis in muscle tissues. We analyzed δ^13C and δ^15N values of young white shark muscle ( n = 21) from Sebastián Vizcaino Bay (SBV) during 2015–2018. We found changes in prey composition across early [neonates, young-of-the-years (YOYs), juveniles] white shark life stages, with significant changes in isotopic composition throughout early ontogeny. Mixing model results indicate a high use of coastal areas for foraging, mainly for juvenile stages and the substantial contribution of pelagic preys (e.g., S. japonicus , Prionotus spp., Cynoscion spp., S. sagax, etc.) in YOYs, white shark diet also indicates an important role of offshore foraging. This change in isotopic composition likely represents the shift from the embryo’s typical maternally derived isotopic signature, incorporated in offshore foraging regions, to the postpartum isotopic composition incorporated by foraging neonates in inshore nursery habitats. This study provides relevant information regarding young white shark feeding preferences, reinforces the importance of coastal areas as critical habitat for the development and the successful foraging of this species, and also provides indirect insights on the feeding habits of the adult female of white sharks, which constitutes a baseline for further research.
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Using stable isotope analysis to understand the migration and Trophic Ecology of northeastern Pacific white sharks (Carcharodon carcharias)
PLoS ONE, 2012Co-Authors: Aaron B Carlisle, Christopher R. Perle, Paul E. Kanive, Sora L. Kim, Taylor K. Chapple, Salvador J Jorgensen, Brice X. Semmens, Scot D Anderson, Daniel J Madigan, Barbara A BlockAbstract:The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the Trophic Ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the Trophic Ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.
Felipe Galván-magaña - One of the best experts on this subject based on the ideXlab platform.
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New insights into the Trophic Ecology of young white sharks (Carcharodon carcharias) in waters off the Baja California Peninsula, Mexico
Marine Biology, 2020Co-Authors: Elena Tamburin, Daniel J Madigan, Fernando R. Elorriaga-verplancken, Colombo Estupiñan-montaño, Alberto Sánchez-gonzález, Mauricio Hoyos Padilla, Michelle Wcisel, Felipe Galván-magañaAbstract:White sharks ( Carcharodon carcharias ) are described as generalist predators, with a demonstrated ontogenetic dietary shift which occurs between subadult and adult life stages. Trophic Ecology studies on white shark have been focused mainly on large and mature individuals, necessitating studies of young white shark Trophic Ecology to better understand their resource use. This study provides new insights into young white shark diet in the North eastern Pacific Ocean using stable isotope analysis in muscle tissues. We analyzed δ^13C and δ^15N values of young white shark muscle ( n = 21) from Sebastián Vizcaino Bay (SBV) during 2015–2018. We found changes in prey composition across early [neonates, young-of-the-years (YOYs), juveniles] white shark life stages, with significant changes in isotopic composition throughout early ontogeny. Mixing model results indicate a high use of coastal areas for foraging, mainly for juvenile stages and the substantial contribution of pelagic preys (e.g., S. japonicus , Prionotus spp., Cynoscion spp., S. sagax, etc.) in YOYs, white shark diet also indicates an important role of offshore foraging. This change in isotopic composition likely represents the shift from the embryo’s typical maternally derived isotopic signature, incorporated in offshore foraging regions, to the postpartum isotopic composition incorporated by foraging neonates in inshore nursery habitats. This study provides relevant information regarding young white shark feeding preferences, reinforces the importance of coastal areas as critical habitat for the development and the successful foraging of this species, and also provides indirect insights on the feeding habits of the adult female of white sharks, which constitutes a baseline for further research.
Barbara A Block - One of the best experts on this subject based on the ideXlab platform.
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Using stable isotope analysis to understand the migration and Trophic Ecology of northeastern Pacific white sharks (Carcharodon carcharias)
PLoS ONE, 2012Co-Authors: Aaron B Carlisle, Christopher R. Perle, Paul E. Kanive, Sora L. Kim, Taylor K. Chapple, Salvador J Jorgensen, Brice X. Semmens, Scot D Anderson, Daniel J Madigan, Barbara A BlockAbstract:The white shark (Carcharodon carcharias) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the Trophic Ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ(13)C) and nitrogen (δ(15)N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ(13)C and δ(15)N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the Trophic Ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.
Frida Ben Rais Lasram - One of the best experts on this subject based on the ideXlab platform.
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Trophic Ecology of Scopoli’s shearwaters during breeding in the Zembra Archipelago (northern Tunisia)
Marine Biology, 2019Co-Authors: Intissar Thabet, Karen Bourgeois, François Loc’h, Aida Abdennadher, Jean-marie Munaron, Manel Gharsalli, Mohamed Salah Romdhane, Frida Ben Rais LasramAbstract:While breeding, seabirds are central-place foragers requiring resources to sustain high-energy requirements. Therefore, during this period, they are particularly sensitive to food-resource availability, which can vary within and between years. Intra- and inter-annual variations in Scopoli’s shearwater ( Calonectris diomedea ) Trophic Ecology were investigated at its largest colony (Zembra Island, 37°07′33″N, 10°48′23″E, Mediterranean Sea). Carbon and nitrogen isotope values were analysed in the blood (adults and chicks) and feathers (adult wing) during pre-laying, incubation, and chick-rearing in 2015 and 2016 to assess variations in stable isotope composition, isotopic niches, Trophic levels, and diet inferred from isotope mixing models. Scopoli’s shearwaters showed variations in isotopes throughout the breeding season and among years, with incubation showing the highest δ^13C and δ^15N values, Trophic levels, inter-annual isotopic niche consistency, and the most specific and narrowest isotopic niche. The difference in blood δ^13C values between adults and chicks suggested Trophic habitat segregation: adults feed inshore, while chicks are fed more oceanic prey. Stable-isotope mixing models based on three potential prey groups revealed that the diet could consist mainly of pelagic fish and crustaceans throughout the breeding season, whereas non-pelagic fish and cephalopods could be consumed more sporadically, mainly during incubation. Feather δ^15N values suggested that the adult diets contained more zooplankton in 2014. These results demonstrated the Scopoli’s shearwater Trophic Ecology plasticity in response to the variable nutritional demands of breeding phases and changes in prey availability. Scopoli’s shearwaters may, thus, be valuable bio-indicators of small pelagic fish populations considered critically depleted in the Mediterranean.
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Trophic Ecology of Scopoli's shearwaters during breeding in the Zembra Archipelago (northern Tunisia)
Marine Biology, 2019Co-Authors: Intissar Thabet, Karen Bourgeois, Aida Abdennadher, Jean-marie Munaron, Manel Gharsalli, Mohamed Salah Romdhane, François Le Loc’h, Frida Ben Rais LasramAbstract:While breeding, seabirds are central-place foragers requiring resources to sustain high-energy requirements. Therefore, during this period, they are particularly sensitive to food-resource availability, which can vary within and between years. Intra- and inter-annual variations in Scopoli's shearwater (Calonectris diomedea) Trophic Ecology were investigated at its largest colony (Zembra Island, 37 degrees 07'33 '' N, 10 degrees 48'23 '' E, Mediterranean Sea). Carbon and nitrogen isotope values were analysed in the blood (adults and chicks) and feathers (adult wing) during pre-laying, incubation, and chick-rearing in 2015 and 2016 to assess variations in stable isotope composition, isotopic niches, Trophic levels, and diet inferred from isotope mixing models. Scopoli's shearwaters showed variations in isotopes throughout the breeding season and among years, with incubation showing the highest delta C-13 and delta N-15 values, Trophic levels, inter-annual isotopic niche consistency, and the most specific and narrowest isotopic niche. The difference in blood delta C-13 values between adults and chicks suggested Trophic habitat segregation: adults feed inshore, while chicks are fed more oceanic prey. Stable-isotope mixing models based on three potential prey groups revealed that the diet could consist mainly of pelagic fish and crustaceans throughout the breeding season, whereas non-pelagic fish and cephalopods could be consumed more sporadically, mainly during incubation. Feather delta N-15 values suggested that the adult diets contained more zooplankton in 2014. These results demonstrated the Scopoli's shearwater Trophic Ecology plasticity in response to the variable nutritional demands of breeding phases and changes in prey availability. Scopoli's shearwaters may, thus, be valuable bio-indicators of small pelagic fish populations considered critically depleted in the Mediterranean.
