School of Environmental and Life Sciences, University of Newcastle, Ourimbah, New South Wales, Australia.
NSW Department of Primary Industries, Fisheries Research, Huskisson, New South Wales, Australia.
Rapid Commun Mass Spectrom. 2023 Feb 28;37(4):e9435. doi: 10.1002/rcm.9435.
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.
We evaluated this by dissecting 76 lobsters and comparing δ C and δ 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.
We found the abdomen δ C values to be lower than other tissues by 0.3 ± 0.2‰ for antennae tissue and 0.1 ± 0.2‰ δ C for leg tissues, whereas for δ 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 C and 3.0‰-4.0‰ for δ N.
We show that S. verreauxi can be sampled non-lethally with mathematical corrections applied for δ C, whereas any tissue is suitable for δ 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.
同位素分析可用于根据猎物氮和碳同位素的同化情况来研究捕食者的饮食。最近的研究表明，从龙虾的腿、触角或腹部提取的组织可以提供不同的饮食指示，但这一点从未在 Sagmariasus verreauxi（东方岩龙虾）身上得到评估。现在需要开展工作，以防止对龙虾食物网得出错误的结论，并开展这项工作可能会导致开发非致死性采样方法。非致死性采样对于龙虾具有伦理价值，对于具有保护意义的区域（如海洋保护区）也具有价值。
我们通过解剖 76 只龙虾，并比较了甲壳长度为 104 至 137 毫米的个体的触角、腿和腹部组织中的 δ C 和 δ N 同位素值，来评估这一点。稳定同位素值使用 Europa EA GSL 元素分析仪与 Hydra 20-20 Isoprime IRMS 联用测定。
我们发现，与触角组织相比，腹部组织的 δ C 值低 0.3±0.2‰，与腿组织相比，腹部组织的 δ C 值低 0.1±0.2‰，而 δ N 则没有观察到组织间的显著差异。龙虾的大小或性别没有显著影响，但我们确实观察到月份和组织类型之间的相互作用，表明差异可能具有季节性。重要的是，组织间检测到的同位素变化范围在用于同位素贝叶斯模型中判别因子的不确定性范围内，即 δ C 为 0‰-1.0‰， δ N 为 3.0‰-4.0‰。
我们表明，可以对 S. verreauxi 进行非致死性采样，并应用数学校正进行 δ C 分析，而 δ N 则适用于任何组织。我们的结果表明，步行腿是最合适的，对龙虾的侵入性也最小。非致死性采样的应用为公民科学对理解龙虾食物网的贡献以及在海洋保护区等生态敏感地区开展实地工作提供了途径。
