scholarly journals Yellowfin tuna (Thunnus albacares) foraging habitat and trophic position in the Gulf of Mexico based on intrinsic isotope tracers

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246082
Author(s):  
Meliza Le-Alvarado ◽  
Alfonsina E. Romo-Curiel ◽  
Oscar Sosa-Nishizaki ◽  
Oscar Hernández-Sánchez ◽  
Leticia Barbero ◽  
...  
Keyword(s):  
Amino Acids ◽  
Gulf Of Mexico ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Management Strategies ◽  
Isotope Analysis ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Important Species ◽  
One Year

Yellowfin tuna (YFT, Thunnus albacares) is a commercially important species targeted by fisheries in the Gulf of Mexico (GM). Previous studies suggest a high degree of residency in the northern GM, although part of the population performs movements to southern Mexican waters. Whether YFT caught in southern waters also exhibit residency or migrate to the northern gulf is currently uncertain, and little is known regarding their trophic ecology. The isotopic composition (bulk & amino acids) of YFT muscle and liver tissues were compared to a zooplankton-based synoptic isoscape from the entire GM to infer feeding areas and estimate Trophic Position (TP). The spatial distribution of δ15Nbulk and δ15NPhe values of zooplankton indicated two distinct isotopic baselines: one with higher values in the northern GM likely driven by denitrification over the continental shelf, and another in the central-southern gulf, where nitrogen fixation predominates. Based on the contribution of the two regional isotopic baselines to YFT tissues, broad feeding areas were inferred, with a greater contribution of the northern GM (over a one-year time scale by muscle), and to a lesser extent in the central-southern GM (over the ca. 6-month scale by liver). This was corroborated by similarities in δ15NPhe values between YFT and the northern GM. TP estimates were calculated based on stable isotope analysis of bulk (SIA) and compound-specific isotope analysis (CSIA-AA) of the canonical source and trophic amino acids. Mean TP based on SIA was 4.9 ± 1.0 and mean TP based on CSIA-A was 3.9 ± 0.2. YFT caught within the Mexican region seem to feed in northern and in central and southern GM, while feeding in the northern GM has a temporal component. Thus, management strategies need to consider that YFT caught in US and Mexican waters are a shared binational resource that exhibit feeding migrations within the GM.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

Trophic ecology of the chihuil sea catfish (Bagre panamensis) in the south-east Gulf of California, México

2017 ◽  
Vol 98 (4) ◽  
pp. 885-893 ◽  
Author(s):  
Víctor M. Muro-Torres ◽  
Felipe Amezcua ◽  
Raul E. Lara-Mendoza ◽  
John T. Buszkiewicz ◽  
Felipe Amezcua-Linares
Keyword(s):  
Gulf Of California ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Demersal Fish ◽  
Trophic Levels ◽  
High Plasticity ◽  
Combined Use ◽  
Ecosystem Based Fisheries Management

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.

scholarly journals Analysis of sizes and state of ovarian maturity in yellowfin tuna (Thunnus albacares) captured in the Gulf of Mexico

2021 ◽  
Vol 9 (10) ◽  
pp. 214-227
Author(s):  
Eduardo Alfredo Zarza Meza ◽  
Fabiola Garcés Díaz ◽  
Rodrigo Cuervo Gonzalez
Keyword(s):  
Gulf Of Mexico ◽  
Fork Length ◽  
Yellowfin Tuna ◽  
Production Costs ◽  
Maturity Stage ◽  
Thunnus Albacares ◽  
Progressive Development ◽  
The Pacific ◽  
Tuna Fishing ◽  
Ovarian Maturity

The yellowfin tuna Thunnus albacares is the second most important fishery in Mexico, due to its production costs and commercial value”  The species is fished on both coast of the country, with the Pacific Ocean presenting productions lightly higher than that of the Gulf of Mexico where, in spite of the above statement, tuna catches have recently shown a downward trend. For this reason, analysis is required of the size and stage of ovarian maturity and it is necessary to determine whether capture size is the primary reason behind the decline in the yellowfin tuna fishery Three tuna fishing trips were conducted in the Gulf of Mexico in order to gather data pertaining to fork length (Lf) and gonads Histological sections were obtained from the latter for analysis and determination of maturity stage. The results showed that males were predominant (40%) among the individuals for which the sex could be differentiated in the catches of T. albacares. The Lf values in the catch, were between 75 and 162 cm. However, variations in this parameter were found between sexes. The relationship between length and weight showed that the males are larger than the females, however, the equationgiven by the parameters of a=0.9406 and b= 3.4504, demonstrated growth of positive allometric type in both sexes. There was progressive development in the state of ovarian maturity over the months of capture. Chromatin nuclear (CN) was the most frequent phase within primary ovarian development (November, February, March), stages were present, although these did not present a direct relationship to fork length.

scholarly journals Trophic Relations of the Red-Necked Grebe on Lakes in the Western Boreal Forest: A Stable-Isotope Analysis

The Condor ◽  
2004 ◽  
Vol 106 (3) ◽  
pp. 638-651 ◽  
Author(s):  
Cynthia A. Paszkowski ◽  
Beverly A. Gingras ◽  
Kayedon Wilcox ◽  
Paul H. Klatt ◽  
William M. Tonn
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Gut Contents ◽  
Isotopic Ratios ◽  
Trophic Relations ◽  
Podiceps Grisegena

Abstract We compared trophic ecology of grebes inferred from stable-isotope analysis to that from gut contents, and compared isotopic ratios of Red-necked Grebes (Podiceps grisegena) from lakes differing in their food webs. Analyses of different grebe tissues (egg yolk and albumen, pectoral and leg muscle, breast and primary feathers) also allowed us to assess the effectiveness of these tissues at representing grebe trophic relations. Isotopic ratios from pectoral and leg muscles were similar, based on comparisons within individual birds. Enriched values of δ15N and δ13C suggested that breast and primary feathers were molted over winter, and therefore reflected a marine food web. Albumen and yolk of grebe eggs and muscle tissues from downy chicks, however, matched isotopic characteristics of the local food web, indicating that female Red-necked Grebes use nutrients from the breeding lake for egg formation. Eggs, therefore, can provide excellent material for isotopic analysis aimed at assessing trophic relations of Red-necked Grebes on breeding lakes. Gut contents and stable isotopes both indicated that grebes from lakes with fish consumed a mixed diet of fish and macroinvertebrates and occupied the highest trophic level, at or above the level of piscivorous fishes. In contrast, grebes from lakes lacking fish occupied a lower trophic position. Relaciones Tróficas de Podiceps grisegena en Lagos del Bosque Boreal del Oeste: Un Análisis de Isótopos Estables Resumen. Comparamos la ecología trófica de Podiceps inferida a partir de análisis de isótopos estables con la de contenidos estomacales y comparamos las relaciones isotópicas de P. grisegena entre lagos que difieren en sus redes tróficas. Los análisis de diferentes tejidos de P. grisegena (yema y albumen del huevo, músculo pectoral y de la pierna, plumas del pecho y primarias) también nos permitieron evaluar la efectividad de estos tejidos para representar las relaciones tróficas de P. grisegena. Las relaciones isotópicas de los músculos pectorales y de las piernas basadas en comparaciones realizadas para cada ave individual fueron similares. Valores enriquecidos de δ15N y δ13C sugirieron que las aves mudaron las plumas del pecho y las primarias durante el invierno, y por lo tanto reflejaron una red trófica marina. El albumen y la yema del huevo de P. grisegena y los tejidos musculares de pichones emplumados, sin embargo, coincidieron con las características isotópicas de la red alimenticia local, indicando que las hembras de P. grisegena usan nutrientes del lago donde nidifican para la formación de los huevos. Los huevos, por lo tanto, pueden constituir un material excelente para análisis isotópicos centrados en evaluar las relaciones tróficas de P. grisegena en los lagos donde se reproducen. Los contenidos estomacales y los isótopos estables indicaron que los individuos de P. grisegena provenientes de lagos con peces consumieron una dieta mixta de peces y macroinvertebrados y ocuparon la posición trófica más alta, al mismo nivel o por arriba de los peces piscívoros. En contraste, los individuos provenientes de lagos sin peces ocuparon una posición trófica menor.

scholarly journals Abyssal deposit feeders are secondary consumers of detritus and rely on nutrition derived from microbial communities in their guts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sonia Romero-Romero ◽  
Elizabeth C. Miller ◽  
Jesse A. Black ◽  
Brian N. Popp ◽  
Jeffrey C. Drazen
Keyword(s):  
Amino Acids ◽  
Trophic Level ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Essential Amino Acids ◽  
Abundant Species ◽  
Abyssal Plain ◽  
Gut Contents ◽  
Deposit Feeders ◽  
Secondary Consumers

AbstractTrophic ecology of detrital-based food webs is still poorly understood. Abyssal plains depend entirely on detritus and are among the most understudied ecosystems, with deposit feeders dominating megafaunal communities. We used compound-specific stable isotope ratios of amino acids (CSIA-AA) to estimate the trophic position of three abundant species of deposit feeders collected from the abyssal plain of the Northeast Pacific (Station M; ~ 4000 m depth), and compared it to the trophic position of their gut contents and the surrounding sediments. Our results suggest that detritus forms the base of the food web and gut contents of deposit feeders have a trophic position consistent with primary consumers and are largely composed of a living biomass of heterotrophic prokaryotes. Subsequently, deposit feeders are a trophic level above their gut contents making them secondary consumers of detritus on the abyssal plain. Based on δ13C values of essential amino acids, we found that gut contents of deposit feeders are distinct from the surrounding surface detritus and form a unique food source, which was assimilated by the deposit feeders primarily in periods of low food supply. Overall, our results show that the guts of deposit feeders constitute hotspots of organic matter on the abyssal plain that occupy one trophic level above detritus, increasing the food-chain length in this detritus-based ecosystem.

scholarly journals Trophic position derived from amino-acid nitrogen isotopes reflect physiological status of both predator and prey over four decades

2021 ◽  
Author(s):  
Agnes ML Karlson ◽  
Caroline Ek ◽  
Douglas Jones
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Baltic Sea ◽  
Food Webs ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Physiological Status ◽  
Ecological Knowledge ◽  
Ecological Data ◽  
Isotope Analyses

AbstractNitrogen isotope analyses of amino-acids (δ15N-AA) are increasingly used to decipher food webs. Interpretation of δ15N-AA in consumers relies on the assumption that physiological status has a negligible influence on the trophic enrichment factor (TEF). Recent experiments have shown that this is not always the case and there is a need to validate derived trophic position (TP) estimates using ecological data. We analyzed δ15N-AA in cod and herring (1980-2019) from the Baltic Sea, a species-poor system where dramatic reduction in condition status of cod has occurred. We expected that TEFcod-herring in trophic AAs would increase during periods of poor cod growth, resulting in inflated TP estimates. We found that TEF and TP estimates were negatively linked to individual condition status, prey fat content and the hypoxic state of the ecosystem. Statistically adjusting for these variables resulted in lower cod TP, highlighting the importance of including ecological knowledge when interpreting TP.Scientific Significance StatementNitrogen stable isotope analyses in amino acids are increasingly used in ecology to understand how environmental change impacts food-webs. Specifically, it is used to more accurately calculate trophic position (TP) of consumers. Controlled experiments have shown that physiological status can alter amino acid isotope composition and TP interpretation, but field studies are lacking. We use 40 years of archived material to demonstrate that TP estimates in Baltic Sea cod and its prey herring are directly related to physiological status. This has important implications for interpreting the real trophic ecology of consumers under environmental stress. By simultaneously measuring condition status in both predator and prey it is possible to adjust for them as confounding variables and decipher actual consumer TP.

scholarly journals Diet Composition and Isotopic Analysis of Nine Important Fisheries Resources in the Eastern Adriatic Sea (Mediterranean)

2021 ◽  
Vol 8 ◽  
Author(s):  
Barbara Zorica ◽  
Daria Ezgeta-Balić ◽  
Olja Vidjak ◽  
Vedran Vuletin ◽  
Marija Šestanović ◽  
...  
Keyword(s):  
Trophic Ecology ◽  
Adriatic Sea ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Isotopic Analysis ◽  
Horse Mackerel ◽  
Size Spectrum ◽  
Fisheries Resources

We examined how the trophic ecology of nine economically important marine taxa varied across three distinct areas of the Adriatic Sea. These taxa included three species of demersal fishes (European hake Merluccius merluccius, red mullet Mullus barbatus, black-bellied angler Lophius budegassa) and two species of decapod crustaceans (Norway lobster Nephrops norvegicus, deep-water rose shrimp Parapenaeus longirostris) and four species of pelagic fishes (sardine Sardina pilchardus, anchovy Engraulis encrasicolus, Mediterranean horse mackerel Trachurus mediterraneus, Atlantic horse mackerel Trachurus trachurus). We used two complementary methods that differed in their temporal context to examine and compare diet. Stomach contents analysis was used to describe the short term diet while stable isotope analysis was used compare long-term assimilated diet. Results showed that although there were spatial differences in what each species consumed, and in their trophic and isotopic niches, each species fed at similar trophic position across locations, indicating similar ecological function. Comparisons of biomass-weighted trophic position (δ15N) and consumer body size (log2 mass) showed evidence for a common isotopic size spectrum across areas, indicating the existence of a size-structured food web. In turn this allowed us to provide a first estimate of the predator–prey body mass ratio (PPMR) for this area (655:1). Results obtained within this study, in future, could be used for ecological modeling and improved long-term management of the Adriatic Sea’s marine resources.

Sign in / Sign up

Export Citation Format

Share Document