Does prey size matter? Novel observations of feeding in the leatherback turtle (
            <i>Dermochelys coriacea</i>
            ) allow a test of predator–prey size relationships

Fossette, Sabrina; Gleiss, Adrian C.; Casey, James P.; Lewis, Andrew R.; Hays, Graeme C.

doi:10.1098/rsbl.2011.0965

Cited by 36 publications

(27 citation statements)

References 16 publications

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“…This is a rather low trophic position for a large marine mega-vertebrate, yet not surprising considering that leatherback turtles consume gelatinous prey [3], [32], [33]. In the eastern Pacific, leatherbacks forage largely on the sea nettle ( Chrysaora fuscescens ) [40, S. Benson, unpubl.…”

Section: Discussionmentioning

confidence: 99%

Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

et al. 2012

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Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea) across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ15N values of bulk skin, with distinct “low δ15N” and “high δ15N” groups. δ15N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ15N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation efforts in light of this species’ imminent risk of extinction in the Pacific.

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Section: Discussionmentioning

confidence: 99%

Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

et al. 2012

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“…A recent update on the optimal foraging theory suggests that imprint from past experience and hunger aversion can also make consumers prefer abundant resources to those rare ones even if the abundant resources are less profitable than the rare ones [25,26]. The component of adaptive interaction switch in the model reflects this updated optimal foraging process of both profit seeking and hunger aversion as the decision of a switch depends on both the benefit (b ji a ij v ij ) and the abundance (R j ) of exploited resources.…”

Section: Discussionmentioning

confidence: 99%

“…Consumers prefer to select highly profitable resources rather than consuming all resources available to them as specified in optimal foraging theory [24]. Concurrently, they will exploit abundant resources over rare ones to avoid risk [25,26]. This adaptive behaviour of interaction switching could well be the predominant process that pushes an ecological network towards becoming compartmentalized or nested, forming a potentially stable and resilient complex community [18,27].…”

Section: Introductionmentioning

confidence: 99%

A hybrid behavioural rule of adaptation and drift explains the emergent architecture of antagonistic networks

2015

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Ecological processes that can realistically account for network architectures are central to our understanding of how species assemble and function in ecosystems. Consumer species are constantly selecting and adjusting which resource species are to be exploited in an antagonistic network. Here we incorporate a hybrid behavioural rule of adaptive interaction switching and random drift into a bipartite network model. Predictions are insensitive to the model parameters and the initial network structures, and agree extremely well with the observed levels of modularity, nestedness and node-degree distributions for 61 real networks. Evolutionary and community assemblage histories only indirectly affect network structure by defining the size and complexity of ecological networks, whereas adaptive interaction switching and random drift carve out the details of network architecture at the faster ecological time scale. The hybrid behavioural rule of both adaptation and drift could well be the key processes for structure emergence in real ecological networks.

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“…western Pacific) and life history stages (i.e. offshore; Fossette et al 2012, Heaslip et al 2012 Examining leatherback diets presents several challenges, as gelatinous zooplankton are understudied compared to other mid-trophic level taxa. This limitation can partially be attributed to the difficulties associated with the collection of fragile gelatinous taxa that are easily destroyed by common sampling techniques (e.g.…”

Section: Introductionmentioning

confidence: 99%

Re-examining trophic dead ends: stable isotope values link gelatinous zooplankton to leatherback turtles in the California Current

Hetherington¹,

Kurle²,

Benson³

et al. 2019

Mar. Ecol. Prog. Ser.

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Predator-prey interactions provide essential information for tracing energy flow through food webs and evaluating the structure and function of ecosystems. In pelagic environments, these interactions are often difficult to discern, which is problematic for identifying specific energy pathways that support populations of protected species. We examined the trophic ecology of an endangered population of leatherback turtles Dermochelys coriacea and their gelatinous prey in the California Current-Large Marine Ecosystem (CC-LME). We combined carbon and nitrogen bulk stable isotope analysis and compound-specific isotope analysis of amino acids (CSIA-AA) with Bayesian statistical approaches to examine the diets of leatherbacks and their prey (scyphozoans and thaliaceans) sampled in the CC-LME. Our objectives were to evaluate (1) temporal changes in leatherback trophic position, (2) the contribution of different gelatinous prey to leather back diets, and (3) trophic structure of the leatherback food web by estimating trophic positions and isotopic niches of leatherbacks and their potential prey. Leatherback trophic positions did not change over time, although carbon isotope values suggest a temporary shift in leatherback habitat in 2005, coincident with anomalous upwelling conditions. Bayesian mixing models suggest that carnivorous sea nettles Chrysaora fuscescens were the largest contributor to leatherback diet, followed by filter-feeding thaliaceans. Isotope analyses provided useful and ecologically realistic estimates of trophic structure, where trophic positions were lowest for thaliaceans, intermediate for scyphozoans, and highest for leatherbacks. Overall, our findings provide information on leatherback foraging ecology over a 13 yr period and the trophic structure of gelatinous zooplankton that support the leatherback population in the CC-LME.

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Does prey size matter? Novel observations of feeding in the leatherback turtle ( Dermochelys coriacea ) allow a test of predator–prey size relationships

Cited by 36 publications

References 16 publications

Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

Stable Isotope Tracking of Endangered Sea Turtles: Validation with Satellite Telemetry and δ15N Analysis of Amino Acids

A hybrid behavioural rule of adaptation and drift explains the emergent architecture of antagonistic networks

Re-examining trophic dead ends: stable isotope values link gelatinous zooplankton to leatherback turtles in the California Current

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