Diet of spiny lobsters from Mahé Island reefs, Seychelles inferred by trophic tracers

Sardenne, Fany; Bodin, Nathalie; Barret, Leo; Blamey, Laura K.; Govinden, Rodney; Gabriel, Kettyna; Mangroo, Rosabella; Munaron, Jean-Marie; Loc’h, François Le; Bideau, Antoine; Grand, Fabienne Le; Sabino, Magali; Bustamante, Paco; Rowat, David

doi:10.1016/j.rsma.2021.101640

Cited by 4 publications

(15 citation statements)

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Section: Discussionmentioning

confidence: 99%

“…When interpreting diets using isotopic Bayesian analysis, diet‐tissue offsets of 0‰–1.0‰ for δ 13 C 19 and 3.0‰–4.0‰ for δ 15 N 11,12 are typically employed. Importantly, our results show that variances in δ 13 C and δ 15 N among the leg, antennae and abdomen tissues of lobsters are within the range of uncertainty typically used in estimating predator diets via Bayesian modelling 11,12,19 . Given our results show that using leg or antennae appendage tissue will not misrepresent lobster food source or trophic level, this confirms the viability of non‐lethal sampling S. verreauxi diets via limb removal.…”

Section: Discussionmentioning

confidence: 99%

“…Stable isotope analysis is possible because “stable” heavy isotopes of carbon ( 13 C) and nitrogen ( 15 N) do not undergo radioactive decay and are retained in tissues over their lighter isotopes ( 12 C and 14 N, respectively, 9 ), and due to this, stable isotopes can be used to measure how energy is transferred through food webs. Given animals acquire the stable isotope composition of their muscle tissues from their diets, isotope analysis allows the structure of food chains and ecosystem linkages through trophic levels to be formally assessed 11–13 . Isotopic changes are shown by delta notation “δ,” which is the convention for reporting ratios of 13 C: 12 C (δ 13 C) and 15 N: 14 N (δ 15 N) isotopes present in tissues, rather than an actual measurement for the isotopes themselves.…”

Section: Introductionmentioning

confidence: 99%

“…Isotopic changes are shown by delta notation “δ,” which is the convention for reporting ratios of 13 C: 12 C (δ 13 C) and 15 N: 14 N (δ 15 N) isotopes present in tissues, rather than an actual measurement for the isotopes themselves. Because isotope ratios derived from prey sources change through time with feeding, if a change in diet occurs, this will be matched by a change in the isotope profile of the consumer's muscle tissue 12,14,15 . In ecological studies, significant changes in δ 13 C often indicate a change in the basal or immediate food source in predator diets, 12,16 whereas significant changes in δ 15 N are more frequently associated with a change in trophic level 11,12 .…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, different tissues can display different rates of isotopic turnover 18,19 . Indeed, previous studies which sampled a range of different tissue types to investigate diets have shown that tissue type can affect the conclusions drawn about predator diets 12,20–22 …”

Section: Introductionmentioning

confidence: 99%

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Non‐lethal sampling does not misrepresent trophic level or dietary sources for Sagmariasus verreauxi (eastern rock lobster)

Day

Knott

Swadling

et al. 2022

Rapid Comm Mass Spectrometry

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Isotope analysis can be used to investigate the diets of predators based on assimilation of nitrogen and carbon isotopes from prey. Recent work has shown that tissues taken from legs, antennae or abdomen of lobsters can give different indications of diet, but this has never been evaluated for Sagmariasus verreauxi (eastern rock lobster). Work is now needed to prevent erroneous conclusions being drawn about lobster food webs, and undertaking this work could lead to developing non-lethal sampling methodologies. Non-lethal sampling for lobsters is valuable both ethically and for areas of conservation significance such as marine reserves.Method: We evaluated this by dissecting 76 lobsters and comparing δ 13 C and δ 15 N isotope values in antennae, leg and abdomen tissue from the same individuals ranging from 104 to 137 mm carapace length. Stable isotope values were determined using a Europa EA GSL elemental analyser coupled with Hydra 20-20 Isoprime IRMS.Results: We found the abdomen δ 13 C values to be lower than other tissues by 0.3 ± 0.2‰ for antennae tissue and 0.1 ± 0.2‰ δ 13 C for leg tissues, whereas for δ 15 N, no significant difference between tissues was observed. There was no significant effect of lobster size or sex, though we did observe interactions between month and tissue type, indicating that differences may be seasonal. Importantly, the detected range of isotopic variability between tissues is within the range of uncertainty used for discrimination factors in isotopic Bayesian modelling of 0‰-1.0‰ for δ 13 C and 3.0‰-4.0‰ for δ 15 N. Conclusions:We show that S. verreauxi can be sampled non-lethally with mathematical corrections applied for δ 13 C, whereas any tissue is suitable for δ 15 N. Our results indicate that a walking leg is most favourable and would also be the least intrusive for the lobster. The application of non-lethal sampling provides avenues for the contribution of citizen science to understanding lobster food webs and to undertake fieldwork in ecologically sensitive areas such as marine reserves.

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Section: Discussionmentioning

confidence: 99%