Yellowfin Tuna

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Felipe Galvanmagana - One of the best experts on this subject based on the ideXlab platform.

  • nitrogen isotopic baselines and implications for estimating foraging habitat and trophic position of Yellowfin Tuna in the indian and pacific oceans
    Deep-sea Research Part Ii-topical Studies in Oceanography, 2015
    Co-Authors: Anne Lorrain, Robert J Olson, Brian N Popp, Brittany S Graham, Felipe Galvanmagana, Valerie Allain, Brian P V Hunt, Michel Potier, Christophe E Menkes, S Kaehler
    Abstract:

    Abstract Assessment of isotopic compositions at the base of food webs is a prerequisite for using stable isotope analysis to assess foraging locations and trophic positions of marine organisms. Our study represents a unique application of stable-isotope analyses across multiple trophic levels (primary producer, primary consumer and tertiary consumer) and over a large spatial scale in two pelagic marine ecosystems. We found that δ 15 N values of particulate organic matter (POM), barnacles and phenylalanine from the muscle tissue of Yellowfin Tuna all showed similar spatial patterns. This consistency suggests that isotopic analysis of any of these can provide a reasonable proxy for isotopic variability at the base of the food web. Secondly, variations in the δ 15 N values of Yellowfin Tuna bulk-muscle tissues paralleled the spatial trends observed in all of these isotopic baseline proxies. Variation in isotopic composition at the base of the food web, rather than differences in Tuna diet, explained the 11‰ variability observed in the bulk-tissue δ 15 N values of Yellowfin Tuna. Evaluating the trophic position of Yellowfin Tuna using amino-acid isotopic compositions across the western Indian and equatorial Pacific Oceans strongly suggests these Tuna occupy similar trophic positions, albeit absolute trophic positions estimated by this method were lower than expected. This study reinforces the importance of considering isotopic baseline variability for diet studies, and provides new insights into methods that can be applied to generate nitrogen isoscapes for worldwide comparisons of top predators in marine ecosystems.

  • biomagnification of mercury and its antagonistic interaction with selenium in Yellowfin Tuna thunnus albacares in the trophic web of baja california sur mexico
    Ecotoxicology and Environmental Safety, 2012
    Co-Authors: Alfredo Ordianoflores, Rene Rosilesmartinez, Felipe Galvanmagana
    Abstract:

    Abstract Mercury and selenium concentrations were determined in muscle of 37 Yellowfin Tuna ( Thunnus albacares ) captured aboard of Mexican purse-seiners boats off western coast of Baja California Sur, between Punta Eugenia and Cabo Falso, from October to December 2006. Also, its prey (mainly, jumbo squid Dosidicus gigas and pelagic red crab Pleuroncodes planipes ) were analyzed from the stomach contents. All the mercury values obtained were lower that mercury content recommended by standard legal limits for seafood adopted by Mexican norms (typically 0.5–1.0 μg g −1 ). Mercury concentrations vary between 0.06 and 0.51 μg g −1 in Yellowfin Tuna, and from 0.01 to 0.20 μg g −1 in its prey, suggesting that mercury can accumulate in prey tissues and that of their predator. Biomagnification factors (BMF) between predator-prey associations were calculated. The BMFs were >1, indicating that mercury biomagnifies along the food web of Yellowfin Tuna. In all species studied there was a molar excess of selenium over mercury. The rank order of mean selenium/mercury molar ratios was for pufferfish (42.62)> diamond squid (15.09)>Yellowfin Tuna (10.29)>pelagic red crab (10.05)>panama lightfish (9.54)> jumbo squid (8.91). The selenium health benefit value (Se-HBV) was calculated to have an improved understanding of the health benefits and risk of fish consumption.

  • bioaccumulation of mercury in muscle tissue of Yellowfin Tuna thunnus albacares of the eastern pacific ocean
    Biological Trace Element Research, 2011
    Co-Authors: Alfredo Ordianoflores, Felipe Galvanmagana, Rene Rosilesmartinez
    Abstract:

    Tuna, like most large pelagic fish, are highly exploited by man, and it is, therefore, important to determine mercury (Hg) levels in these species in order to establish allowable limits for their consumption and/or contamination levels in the environment. In this study, we evaluated Hg accumulation in Yellowfin Tuna (Thunnus albacares) muscle in two different geographic sites of the eastern Pacific Ocean. There was a positive association between Hg content and Tuna size in the equatorial zone (EQZ). Using adjusted sizes, the site of origin was a determinant factor in Hg accumulation. Sex, by contrast, did not affect Hg levels, suggesting that males and females have similar feeding habits. No Hg concentration was over the Hg content thresholds for large marine predators adopted by Mexican norms and by North American authorities (1 μg g−1 w.w.). Hg input due to Yellowfin Tuna consumption represented from 9.84% to 35.87% in Baja California Sur and from 14.78% to 53.87% in EQZ of the provisional tolerable weekly intake adopted by the World Health Organization. The target hazard quotient for Hg was <1 in each group of the population studied, which indicates that consumption of Yellowfin Tuna is not a threat to human health.

  • food web inferences of stable isotope spatial patterns in copepods and Yellowfin Tuna in the pelagic eastern pacific ocean
    Progress in Oceanography, 2010
    Co-Authors: Robert J Olson, Brian N Popp, Brittany S Graham, Gladis A Lopezibarra, Felipe Galvanmagana, Cleridy E Lennertcody, Noemi Bocanegracastillo, Natalie J Wallsgrove, Elizabeth Gier, Vanessa Alatorreramirez
    Abstract:

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and Yellowfin Tuna (Thunnus albacares), and to quantify Yellowfin Tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ15N values of several omnivorous copepod species, we examined isotopic spatial relationships among Yellowfin Tuna and copepods. We found a broad-scale, uniform gradient in δ15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ15N values in the white muscle of Yellowfin Tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ15N values at the base of the food web, the isotopic difference between these two taxa, “ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin Tuna trophic-position estimates based on their bulk δ15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore–offshore, east to west gradient in Yellowfin Tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of Yellowfin Tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin Tuna stomach contents did not show a regular inshore–offshore gradient in trophic position during 2003–2005, but the trophic-position estimates based on both methods had similar scales of variability. We conclude that trophic status of Yellowfin Tuna increased significantly from east to west over the study area based on the spatial pattern of ΔYFT-COP values and the difference between the δ15N values of glutamic acid and glycine, “trophic” and “source” amino acids, respectively. These results provide improved depictions of trophic links and biomass flows for food-web models, effective tools to evaluate climate and fishing effects on exploited ecosystems.

Swaraj Priyaranjan Kunal - One of the best experts on this subject based on the ideXlab platform.

  • mitochondrial dna analysis reveals three stocks of Yellowfin Tuna thunnus albacares bonnaterre 1788 in indian waters
    Conservation Genetics, 2013
    Co-Authors: Swaraj Priyaranjan Kunal, Girish Kumar, Maria Rosalia Menezes, Ram Murti Meena
    Abstract:

    Yellowfin Tuna (Thunnus albacares) is an epipelagic, oceanic species of family Scombridae found in tropical and subtropical region of Pacific, Indian and Atlantic Ocean. It is commercially important fish and accounts for 19 % of total Tuna catches in Indian waters. In present study, population structure of Yellowfin Tuna was examined using sequence analysis of mitochondrial DNA from seven geographically distinct locations along the Indian coast. A 500 bp segment of D-loop region was sequenced and analysed for 321 Yellowfin samples. Hierarchical analysis of molecular variance showed significant genetic differentiation among three groups (VE); (AG); (KO, TU, PO, VI, PB) analyzed (Φ ST  = 0.03844, P ≤ 0.001). In addition, spatial analysis of molecular variance identified three genetically heterogeneous groups of Yellowfin Tuna in Indian waters. Results were further corroborated by significant value of nearest neighbour statistic (S nn = 0.261, P ≤ 0.001). Thus finding of this study rejects the null hypothesis of single panmictic population of Yellowfin Tuna in Indian waters.

Brian N Popp - One of the best experts on this subject based on the ideXlab platform.

  • nitrogen isotopic baselines and implications for estimating foraging habitat and trophic position of Yellowfin Tuna in the indian and pacific oceans
    Deep-sea Research Part Ii-topical Studies in Oceanography, 2015
    Co-Authors: Anne Lorrain, Robert J Olson, Brian N Popp, Brittany S Graham, Felipe Galvanmagana, Valerie Allain, Brian P V Hunt, Michel Potier, Christophe E Menkes, S Kaehler
    Abstract:

    Abstract Assessment of isotopic compositions at the base of food webs is a prerequisite for using stable isotope analysis to assess foraging locations and trophic positions of marine organisms. Our study represents a unique application of stable-isotope analyses across multiple trophic levels (primary producer, primary consumer and tertiary consumer) and over a large spatial scale in two pelagic marine ecosystems. We found that δ 15 N values of particulate organic matter (POM), barnacles and phenylalanine from the muscle tissue of Yellowfin Tuna all showed similar spatial patterns. This consistency suggests that isotopic analysis of any of these can provide a reasonable proxy for isotopic variability at the base of the food web. Secondly, variations in the δ 15 N values of Yellowfin Tuna bulk-muscle tissues paralleled the spatial trends observed in all of these isotopic baseline proxies. Variation in isotopic composition at the base of the food web, rather than differences in Tuna diet, explained the 11‰ variability observed in the bulk-tissue δ 15 N values of Yellowfin Tuna. Evaluating the trophic position of Yellowfin Tuna using amino-acid isotopic compositions across the western Indian and equatorial Pacific Oceans strongly suggests these Tuna occupy similar trophic positions, albeit absolute trophic positions estimated by this method were lower than expected. This study reinforces the importance of considering isotopic baseline variability for diet studies, and provides new insights into methods that can be applied to generate nitrogen isoscapes for worldwide comparisons of top predators in marine ecosystems.

  • food web inferences of stable isotope spatial patterns in copepods and Yellowfin Tuna in the pelagic eastern pacific ocean
    Progress in Oceanography, 2010
    Co-Authors: Robert J Olson, Brian N Popp, Brittany S Graham, Gladis A Lopezibarra, Felipe Galvanmagana, Cleridy E Lennertcody, Noemi Bocanegracastillo, Natalie J Wallsgrove, Elizabeth Gier, Vanessa Alatorreramirez
    Abstract:

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and Yellowfin Tuna (Thunnus albacares), and to quantify Yellowfin Tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ15N values of several omnivorous copepod species, we examined isotopic spatial relationships among Yellowfin Tuna and copepods. We found a broad-scale, uniform gradient in δ15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ15N values in the white muscle of Yellowfin Tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ15N values at the base of the food web, the isotopic difference between these two taxa, “ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin Tuna trophic-position estimates based on their bulk δ15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore–offshore, east to west gradient in Yellowfin Tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of Yellowfin Tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin Tuna stomach contents did not show a regular inshore–offshore gradient in trophic position during 2003–2005, but the trophic-position estimates based on both methods had similar scales of variability. We conclude that trophic status of Yellowfin Tuna increased significantly from east to west over the study area based on the spatial pattern of ΔYFT-COP values and the difference between the δ15N values of glutamic acid and glycine, “trophic” and “source” amino acids, respectively. These results provide improved depictions of trophic links and biomass flows for food-web models, effective tools to evaluate climate and fishing effects on exploited ecosystems.

  • A rapid ontogenetic shift in the diet of juvenile Yellowfin Tuna from Hawaii
    Marine Biology, 2007
    Co-Authors: Brittany S Graham, Dean Grubbs, Kim Holland, Brian N Popp
    Abstract:

    Within the tropical and subtropical oceans, Tuna forage opportunistically on a wide variety of prey. However, little is known about the trophic ecology of the smallest size classes which play an important role in stock assessments and fisheries management. The foraging behavior of Yellowfin Tuna, Thunnus albacares (23.5–154.0 cm FL), collected from nearshore Fish Aggregating Devices (FADs) around Oahu was studied using stable isotope and stomach contents analyses. Emphasis was placed on small juveniles. Yellowfin Tuna changed their diets significantly between 45 and 50 cm forklength (ca. 1.5 kg). Smallest size classes fed on planktonic organisms inhabiting the shallow mixed layer, primarily larval stomatopod and decapod crustaceans, whereas larger Tuna fed on teleosts and adult Oplophorus gracilirostris , a vertically migrating mesopelagic species of shrimp. When interpreting the variation in prey δ ^15N values, we considered both their relative trophic position and δ ^15N values of the nitrogen at the base of the food web. Based on the distinct diet shift of the Yellowfin Tuna, demonstrated by both isotope and stomach content analyses, we propose a critical mass threshold was reached at about 45 cm FL that enabled sufficient endothermic capability to allow Tuna to access prey dwelling in deeper, colder water. These ontogenetic changes in foraging range and commensurate shift in diet of small Tunas would affect their vulnerability to fishing pressure.

Yeunsuk Gu - One of the best experts on this subject based on the ideXlab platform.

  • extracting optimization and physical properties of Yellowfin Tuna thunnus albacares skin gelatin compared to mammalian gelatins
    Food Hydrocolloids, 2005
    Co-Authors: Yeunsuk Gu
    Abstract:

    Abstract This work is to optimize gelatin extraction from dorsal skin of Yellowfin Tuna (Thunnus albacares) using response surface methodology, and to compare physical properties of Yellowfin Tuna skin gelatin with those of two mammalian skin gelatins (bovine and porcine). Central composite design was adopted in gelatin processing for extracting optimization. Concentration of NaOH (X1), treatment time (X2), extraction temperature (X3) and extraction time (X4) were chosen for independent variables. Dependent variables were gel strength (Y1) and gelatin content (Y2). Optimal conditions were X1=1.89(%), X2=2.87 (days), X 3 =58.15 (° C ) and X4=4.72 (h), and predicted values of multiple response optimal conditions were Y1=429.1 (Bloom) and Y2=89.7 (%). In order to investigate physical properties of Yellowfin Tuna skin gelatin, gel strength, gelling and melting points, and dynamic viscoelastic properties were measured. The gel strength of Yellowfin Tuna skin gelatin (426 Bloom) was higher than bovine and porcine gelatins (216 Bloom and 295 Bloom, respectively), while gelling and melting points were lower. Dynamic viscoelastic properties of Yellowfin Tuna skin gelatin did not change at 20 °C, but increase at 10 °C as a similar pattern with mammalian gelatins.

Brittany S Graham - One of the best experts on this subject based on the ideXlab platform.

  • nitrogen isotopic baselines and implications for estimating foraging habitat and trophic position of Yellowfin Tuna in the indian and pacific oceans
    Deep-sea Research Part Ii-topical Studies in Oceanography, 2015
    Co-Authors: Anne Lorrain, Robert J Olson, Brian N Popp, Brittany S Graham, Felipe Galvanmagana, Valerie Allain, Brian P V Hunt, Michel Potier, Christophe E Menkes, S Kaehler
    Abstract:

    Abstract Assessment of isotopic compositions at the base of food webs is a prerequisite for using stable isotope analysis to assess foraging locations and trophic positions of marine organisms. Our study represents a unique application of stable-isotope analyses across multiple trophic levels (primary producer, primary consumer and tertiary consumer) and over a large spatial scale in two pelagic marine ecosystems. We found that δ 15 N values of particulate organic matter (POM), barnacles and phenylalanine from the muscle tissue of Yellowfin Tuna all showed similar spatial patterns. This consistency suggests that isotopic analysis of any of these can provide a reasonable proxy for isotopic variability at the base of the food web. Secondly, variations in the δ 15 N values of Yellowfin Tuna bulk-muscle tissues paralleled the spatial trends observed in all of these isotopic baseline proxies. Variation in isotopic composition at the base of the food web, rather than differences in Tuna diet, explained the 11‰ variability observed in the bulk-tissue δ 15 N values of Yellowfin Tuna. Evaluating the trophic position of Yellowfin Tuna using amino-acid isotopic compositions across the western Indian and equatorial Pacific Oceans strongly suggests these Tuna occupy similar trophic positions, albeit absolute trophic positions estimated by this method were lower than expected. This study reinforces the importance of considering isotopic baseline variability for diet studies, and provides new insights into methods that can be applied to generate nitrogen isoscapes for worldwide comparisons of top predators in marine ecosystems.

  • food web inferences of stable isotope spatial patterns in copepods and Yellowfin Tuna in the pelagic eastern pacific ocean
    Progress in Oceanography, 2010
    Co-Authors: Robert J Olson, Brian N Popp, Brittany S Graham, Gladis A Lopezibarra, Felipe Galvanmagana, Cleridy E Lennertcody, Noemi Bocanegracastillo, Natalie J Wallsgrove, Elizabeth Gier, Vanessa Alatorreramirez
    Abstract:

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and Yellowfin Tuna (Thunnus albacares), and to quantify Yellowfin Tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ15N values of several omnivorous copepod species, we examined isotopic spatial relationships among Yellowfin Tuna and copepods. We found a broad-scale, uniform gradient in δ15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ15N values in the white muscle of Yellowfin Tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ15N values at the base of the food web, the isotopic difference between these two taxa, “ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin Tuna trophic-position estimates based on their bulk δ15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore–offshore, east to west gradient in Yellowfin Tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of Yellowfin Tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin Tuna stomach contents did not show a regular inshore–offshore gradient in trophic position during 2003–2005, but the trophic-position estimates based on both methods had similar scales of variability. We conclude that trophic status of Yellowfin Tuna increased significantly from east to west over the study area based on the spatial pattern of ΔYFT-COP values and the difference between the δ15N values of glutamic acid and glycine, “trophic” and “source” amino acids, respectively. These results provide improved depictions of trophic links and biomass flows for food-web models, effective tools to evaluate climate and fishing effects on exploited ecosystems.

  • A rapid ontogenetic shift in the diet of juvenile Yellowfin Tuna from Hawaii
    Marine Biology, 2007
    Co-Authors: Brittany S Graham, Dean Grubbs, Kim Holland, Brian N Popp
    Abstract:

    Within the tropical and subtropical oceans, Tuna forage opportunistically on a wide variety of prey. However, little is known about the trophic ecology of the smallest size classes which play an important role in stock assessments and fisheries management. The foraging behavior of Yellowfin Tuna, Thunnus albacares (23.5–154.0 cm FL), collected from nearshore Fish Aggregating Devices (FADs) around Oahu was studied using stable isotope and stomach contents analyses. Emphasis was placed on small juveniles. Yellowfin Tuna changed their diets significantly between 45 and 50 cm forklength (ca. 1.5 kg). Smallest size classes fed on planktonic organisms inhabiting the shallow mixed layer, primarily larval stomatopod and decapod crustaceans, whereas larger Tuna fed on teleosts and adult Oplophorus gracilirostris , a vertically migrating mesopelagic species of shrimp. When interpreting the variation in prey δ ^15N values, we considered both their relative trophic position and δ ^15N values of the nitrogen at the base of the food web. Based on the distinct diet shift of the Yellowfin Tuna, demonstrated by both isotope and stomach content analyses, we propose a critical mass threshold was reached at about 45 cm FL that enabled sufficient endothermic capability to allow Tuna to access prey dwelling in deeper, colder water. These ontogenetic changes in foraging range and commensurate shift in diet of small Tunas would affect their vulnerability to fishing pressure.