Bouchard C, Nicolas D
UMR 1224 ECOBIOP, Université de Pau et des Pays de l'Adour, Saint-Pée-sur-Nivelle, France.
Tour du Valat Research Institute, Arles, France.
J Fish Biol. 2023 Nov;103(5):1113-1121. doi: 10.1111/jfb.15514. Epub 2023 Aug 9.
Migration speed can have important evolutionary consequences as it can affect the timing of arrival, remaining energy reserves, and habitat choice. Environmental conditions and individual phenotypic traits can impact the migration speed of individuals. In this way, estimating migration speed is of particular importance, especially for species under strong management strategies and colonizing highly diversified habitats, as is the case for the European eel. However, estimating the migration speed of glass eels, which is the life stage when eels colonize continental habitats, presents challenges due to typically low re-capture probabilities and difficulties in tagging individuals. Using recruitment time series at two sites, one at the sea connection and another inland, we estimated the temporal lag between the two migration peaks to compute migration speed. Because we worked on the Mediterranean coasts and in a lagoon, the weak tidal amplitudes may inhibit individuals from efficiently performing the selective tidal stream transport. We obtained migration speed values coherent with the few values available in the literature for Atlantic estuaries. The values we obtained that are lower than those obtained for Atlantic estuaries are also coherent with the weak tides along the Mediterranean coasts and lead to necessary further studies to understand the migratory behavior of glass eels in such hydro-systems.
洄游速度可能会产生重要的进化后果，因为它会影响到达时间、剩余能量储备和栖息地选择。环境条件和个体表型特征会影响个体的洄游速度。因此，估计洄游速度尤为重要，特别是对于处于严格管理策略下且在高度多样化栖息地中定殖的物种，欧洲鳗鲡就是如此。然而，估计玻璃鳗（即鳗鲡定殖到大陆栖息地的生命阶段）的洄游速度存在挑战，因为通常重捕概率较低且给个体标记存在困难。利用两个地点（一个在与海洋相连处，另一个在内陆）的补充时间序列，我们估计了两个洄游高峰之间的时间滞后以计算洄游速度。由于我们在地中海沿岸和一个泻湖开展研究，微弱的潮汐幅度可能会阻碍个体有效地进行选择性潮汐流运输。我们获得的洄游速度值与文献中关于大西洋河口的少数可用值一致。我们获得的低于大西洋河口的值也与地中海沿岸微弱的潮汐相符，并导致有必要进行进一步研究以了解玻璃鳗在这种水文系统中的洄游行为。
