Global trophic ecology of yellowfin, bigeye, and albacore tunas: Understanding predation on micronekton communities at ocean-basin scales

Duffy, Leanne M.; Kuhnert, Petra M.; Pethybridge, Heidi; Young, Jock; Olson, Robert J.; Logan, John M.; Goñi, Nicolás; Romanov, Evgeny V.; Allain, Valérie; Staudinger, Michelle D.; Abécassis, Mélanie; Choy, C. Anela; Hobday, Alistair J.; Simier, Monique; Galván‐Magaña, Felipe; Potier, Michel; Ménard, Frédéric

doi:10.1016/j.dsr2.2017.03.003

Cited by 67 publications

(57 citation statements)

References 101 publications

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“…Additionally, diet information gathered from trawl-collected specimens can overestimate feeding rations and skew predator–prey relationships due to post-capture net feeding [ 8 , 61 ]. While a highly valuable source of data, diet from SCA generally provides a short-term snapshot of ingested food items, and both is sample-intensive and requires precise and detailed taxonomic expertise [ 6 , 7 , 43 , 56 ]. ROVs, on the other hand, while well suited for high resolution, in situ observations, are potentially subject to avoidance by at least some taxa that are sensitive to noise and light, and are mobile enough to escape [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

Deep pelagic food web structure as revealed by in situ feeding observations

Choy¹,

Haddock²,

Robison³

2017

Proc. R. Soc. B.

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103

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Food web linkages, or the feeding relationships between species inhabiting a shared ecosystem, are an ecological lens through which ecosystem structure and function can be assessed, and thus are fundamental to informing sustainable resource management. Empirical feeding datasets have traditionally been painstakingly generated from stomach content analysis, direct observations and from biochemical trophic markers (stable isotopes, fatty acids, molecular tools). Each approach carries inherent biases and limitations, as well as advantages. Here, using 27 years (1991–2016) of in situ feeding observations collected by remotely operated vehicles (ROVs), we quantitatively characterize the deep pelagic food web of central California within the California Current, complementing existing studies of diet and trophic interactions with a unique perspective. Seven hundred and forty-three independent feeding events were observed with ROVs from near-surface waters down to depths approaching 4000 m, involving an assemblage of 84 different predators and 82 different prey types, for a total of 242 unique feeding relationships. The greatest diversity of prey was consumed by narcomedusae, followed by physonect siphonophores, ctenophores and cephalopods. We highlight key interactions within the poorly understood ‘jelly web’, showing the importance of medusae, ctenophores and siphonophores as key predators, whose ecological significance is comparable to large fish and squid species within the central California deep pelagic food web. Gelatinous predators are often thought to comprise relatively inefficient trophic pathways within marine communities, but we build upon previous findings to document their substantial and integral roles in deep pelagic food webs.

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Section: Discussionmentioning

confidence: 99%

Deep pelagic food web structure as revealed by in situ feeding observations

Choy¹,

Haddock²,

Robison³

2017

Proc. R. Soc. B.

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103

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“…Interspecific differences in the feeding ecology of tunas have been detected within regions and related to variations in vertical habitat usage and associated prey availability (Duffy et al, ). In this study, bigeye had the highest mean global and regional TPs, reaffirming that this species forages in deeper waters and consumes deeper‐living prey such as ommastrephid squid, paralepidid fishes and decapod shrimps (Duffy et al, ).…”

Section: Discussionmentioning

confidence: 99%

A global meta‐analysis of marine predator nitrogen stable isotopes: Relationships between trophic structure and environmental conditions

Pethybridge

Choy

Logan

et al. 2018

Global Ecol Biogeogr

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Aim:We examined potential environmental drivers of broad-scale spatial patterns in the trophic structure of marine ecosystems as represented by nitroge-n stable isotopes in globally distributed marine predators. Additionally, we assessed the effects of spatial scale on the predictive capabilities of environmental variables.Location: Global oceans. Time period: 2000 to 2015.Major taxa studied: Tunas: Thunnus albacares, Thunnus obesus, Thunnus alalunga. Methods:We undertook a global compilation and meta-analysis of the bulk nitrogen stable isotope ratios (δ 15 N values) of three tuna species (n = 4,281). After adjusting for regional variations in baseline δ 15 N values using a global ocean biogeochemistry model, generalized additive mixed models were employed to infer global-scale oceanographic controls of trophic structure, using cosmopolitan tuna species as a model. Results: For the three tuna species, variation in trophic position estimated using bulk δ 15 N values was largely explained by geographical location and the corresponding oxygen minimum layer depth. Tuna trophic positions declined in areas with reduced oxygen at depth. Food-chain length, as captured by maximum trophic position, was longer in areas of the western Pacific Ocean and shorter in the northern Atlantic and eastern Pacific Oceans. Trophic adaptability of the tuna predators, as indicated by intraspecific variability, was highest in the western and central Pacific Ocean and lowest in the northern AtlanticOcean. Our analysis demonstrated that while tunas share similar functional trophic roles, deeper-foraging tuna species had higher trophic positions globally. The predictive capacity of environmental variables decreased at finer (regional) spatial scales. Main conclusions:Our work suggests that habitat compression resulting from the predicted global expansion of oxygen minimum zones with ocean warming will impact the

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“…In the eastern Atlantic Ocean, around 200 000 tons of BET and YFT are caught each year, leading to an overexploitation of these species (ICCAT 2015). Tunas occupy high trophic positions in pelagic habitats and their biomass reduction induced by fishing raises concerns about the health of both tuna populations and pelagic ecosystems, especially in a global change context (Chust et al 2014, Duffy et al 2017. This is a topical issue within the Gulf of Guinea, a productive ecosystem that supports complex food webs, which has been subject to increased pressure from commercial fisheries, human population growth and pollution from domestic and industrial sources in the adjacent countries (Aryeetey 2002, Ukwe et al 2006.…”

Section: Introductionmentioning

confidence: 99%

“…In the eastern Atlantic Ocean, more than 160 prey taxa have been identified in their stomach content (Dragovich 1970, Dragovich andPotthoff 1972) indicating that diet variability is linked to environmental conditions (e.g. sea surface temperature and mixed-layer depth) (Weng et al 2009, Parrish et al 2015, Duffy et al 2017). In the Atlantic Ocean, tropical tunas take advantage of prey aggregations, such as the mesopelagics lightfish Vinciguerria nimbaria (Ménard and Marchal 2003) and the cigarfish Cubiceps pauciradiatus (Ménard et al 2000, Bard et al 2002.…”

Section: Introductionmentioning

confidence: 99%

Seasonal habitat and length influence on the trophic niche of co-occurring tropical tunas in the eastern Atlantic Ocean

Sardenne

Diaha

Amandé

et al. 2019

Can. J. Fish. Aquat. Sci.

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In the Gulf of Guinea, bigeye tuna (Thunnus obesus; BET) and yellowfin tuna (Thunnus albacares; YFT) are an important part of commercial fisheries and play a prominent ecological role as top predators. Using fatty acid profiles and carbon and nitrogen stable isotopes, we examined their trophic niche partitioning in this understudied region. Trophic niche overlap was high (>70%), similar to percentages in other ocean basins. BET occupied a higher trophic position than YFT and fed on deeper prey (high δ15N values and high proportions of monounsaturated fatty acids). The trophic position of YFT decreased slightly in the last 15 years (δ15N values decreased by ∼0.5‰), suggesting a change in epipelagic communities, as observed in the eastern Pacific Ocean. Ontogenic changes were limited to BET. For both species, the dietary proportion of the diatom marker 20:5(n-3) increased in the seasonal upwelling area, highlighting the influence of seasonal habitat on the diet of tuna. The relatively lipid-rich muscle (∼6% dry mass) of Atlantic tropical tuna suggests a richer diet in this region than that of Indian Ocean tropical tuna and (or) differences in energy allocation strategies.

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Global trophic ecology of yellowfin, bigeye, and albacore tunas: Understanding predation on micronekton communities at ocean-basin scales

Abstract: International audienc

Cited by 67 publications

References 101 publications

Deep pelagic food web structure as revealed by in situ feeding observations

Deep pelagic food web structure as revealed by in situ feeding observations

A global meta‐analysis of marine predator nitrogen stable isotopes: Relationships between trophic structure and environmental conditions

Seasonal habitat and length influence on the trophic niche of co-occurring tropical tunas in the eastern Atlantic Ocean

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