Element concentrations and fatty acid profiles in American lobster (Homarus americanus) from the Bay of Fundy and Gulf of St. Lawrence

Recent investigations suggested a northward and eastward habitat shift of American lobster (Homarus americanus) from the Bay of Fundy (BoF) to waters of the Gulf of St Lawrence (GSL). In this context, we conducted comparative analyses of fatty acids (FA) and 16 elements of physiological measures across lobster tissues (hepatopancreas, muscle, shell) through multivariate statistical methods High levels of n-3 polyunsaturated FA (PUFA): EPA (C20:5n3) and DHA (C22:6n3) and planktonic based diet for GSL lobsters suggests higher quality in addition to anti-inflammatory markers (FA ratios). In contrast, BoF lobsters recorded higher concentrations of C18:1n9, C20:3n6, and C18:2n6 indicators of inflammation, carnivorous diet and oxidative stress. Similarly, Principal Component Analyses (PCA) displayed strong clustering of toxic elements (Hg, Cd) with pro-inflammatory FA in BoF. This pattern could be related to environmental conditions and altered food sources differences in the two ecosystems of GSL and BoF. Furthermore, inflammatory signs in BoF are always associated with shell disease in lobsters. Finally, abundance invasive species, particularly green crab (Carcinus maenas) in BoF act as both a physiological stressor and an ecological competitor for lobsters in BoF that are not present in GSL. Control of the invasive organism could enhance lobster abundance, health and habitat stability. Our findings reinforce the idea that local environmental stressors and biotic interactions with lobster influence abundance and health and drive the lobster distributional habitat shift toward less desirable southeastern Atlantic areas to more balanced ecosystems currently existent in the more northwest Atlantic areas.

近期研究表明，美洲螯龙虾（American lobster, *Homarus americanus*）的栖息范围正从芬迪湾（Bay of Fundy, BoF）向圣劳伦斯湾（Gulf of St Lawrence, GSL）海域北向东向迁移。基于此研究背景，本研究通过多变量统计方法，对美洲螯龙虾不同组织（肝胰腺、肌肉、外壳）内的脂肪酸（fatty acids, FA）及16项生理相关元素开展了对比分析。圣劳伦斯湾螯龙虾体内的n-3多不饱和脂肪酸（n-3 polyunsaturated FA, PUFA）——二十碳五烯酸（EPA, C20:5n3）与二十二碳六烯酸（DHA, C22:6n3）——含量较高，且食性以浮游生物为主，这不仅体现出其品质更优，同时也反映出抗炎相关指标（脂肪酸比值）的优势。与之形成对照的是，芬迪湾螯龙虾体内的C18:1n9、C20:3n6及C18:2n6浓度更高，这些物质分别为炎症、肉食性食性与氧化应激的指示物。主成分分析（Principal Component Analyses, PCA）结果同样显示，芬迪湾螯龙虾体内的有毒元素（汞Hg、镉Cd）与促炎性脂肪酸呈现出显著的聚类特征。该分布模式可能与芬迪湾与圣劳伦斯湾两个生态系统的环境差异以及食物来源改变有关。此外，芬迪湾螯龙虾的炎症相关症状往往与其外壳病害存在关联。最后，芬迪湾内大量存在的入侵物种——尤其是欧洲绿蟹（green crab, *Carcinus maenas*）——会对当地螯龙虾同时构成生理胁迫与生态竞争，而圣劳伦斯湾并无此类入侵物种。对该入侵物种进行管控，有助于提升螯龙虾的种群数量、健康水平与栖息地稳定性。本研究结果进一步印证了以下观点：当地环境胁迫因子以及与螯龙虾相关的生物交互作用，会影响螯龙虾的种群数量与健康状态，并推动其栖息范围从环境欠佳的大西洋东南部区域，向当前大西洋西北部生态系统更为平衡的区域迁移。