Data from Natural geochemical markers reveal environmental history and population connectivity of common cuttlefish in the Atlantic Ocean and Mediterranean Sea

Natural markers (δ13C and δ18O stable isotopes) in the cuttlebones of the European common cuttlefish (Sepia officinalis) were determined for individuals collected across a substantial portion of their range in the Northeast Atlantic Ocean (NEAO) and Mediterranean Sea. Cuttlebone δ13C and δ18O were quantified for core and edge material to characterize geochemical signatures associated with early (juvenile) and recent (sub-adult/adult) life-history periods, respectively. Regional shifts in cuttlebone δ13C and δ18O values were detected across the 12 sites investigated. Individuals collected from sites in the NEAO displayed more enriched δ13C and δ18O values relative to sites in the Mediterranean Sea, with the latter also showing salient differences in both markers among western, central and eastern collection areas. Classification success based on cuttlebone δ13C and δ18O values to four geographical regions (NEAO, western, central and eastern Mediterranean Sea) was relatively high, suggesting that environmental conditions in each region were distinct and produced area-specific geochemical signatures on the cuttlebones of S. officinalis. A modified δ13C and δ18O baseline was developed from sites proximal to the Strait of Gibraltar in both the NEAO and Mediterranean Sea to assess potential mixing through this corridor. Nearly, all (95%) of δ13C and δ18O signatures of S. officinalis collected in the area of the NEAO closest to the Strait of Gibraltar (Gulf of Cadiz) matched the signatures of specimens collected in the western Mediterranean, signifying potential movement and mixing of individuals through this passageway. This study extends the current application of these geochemical markers for assessing the natal origin and population connectivity of this species and potentially other taxa that inhabit this geographical area.

本研究对东北大西洋（Northeast Atlantic Ocean, NEAO）与地中海的大部分分布区域内采集的欧洲普通乌贼（Sepia officinalis）个体的乌贼骨中的天然标记物（δ13C与δ18O稳定同位素）进行了测定。研究分别对乌贼骨的核心组织与边缘组织中的δ13C和δ18O进行定量分析，以分别表征对应于早期（幼体阶段）和近期（亚成体/成体阶段）生活史时期的地球化学特征。在本次调研的12个采样点中，均检测到乌贼骨δ13C与δ18O值的区域差异。相较于地中海区域的采样点，东北大西洋采样点采集的个体其δ13C与δ18O值更为富集；同时地中海区域的采样点在两类标记物上也呈现出西部、中部与东部采集区域间的显著差异。基于乌贼骨δ13C与δ18O值对四个地理区域（东北大西洋、地中海西部、中部与东部）的个体进行分类的准确率相对较高，这表明各区域的环境条件存在差异，并在欧洲普通乌贼的乌贼骨上形成了区域专属的地球化学特征。本研究以东北大西洋与地中海区域内靠近直布罗陀海峡（Strait of Gibraltar）的采样点为基础，构建了修正后的δ13C与δ18O基准值，用于评估个体通过该海峡通道的潜在种群混合情况。在东北大西洋最靠近直布罗陀海峡的区域（加的斯湾，Gulf of Cadiz）采集的欧洲普通乌贼个体，其δ13C与δ18O特征中有95%与地中海西部采集的样本特征相匹配，这表明个体可通过该通道进行移动与种群混合。本研究拓展了这类地球化学标记物的现有应用场景，可用于评估该物种乃至该地理区域内其他栖息类群的出生地起源与种群连通性。