Futia Matthew H, Marsden J Ellen
Rubenstein Ecosystem Science Laboratory, University of Vermont, Burlington, Vermont, USA.
J Fish Biol. 2025 Aug;107(2):613-627. doi: 10.1111/jfb.70071. Epub 2025 May 2.
Hatchery practices are a critical tool of fisheries management to supplement diminished fish populations and restore extirpated species. However, stocking programs that successfully restore self-sustaining populations are rare. Unintentional artificial selection and domestication of hatchery-reared fish are potential limitations to the success of stocked individuals by selecting for behaviours that are poorly suited for natural conditions. Here, we compared seasonal movement behaviours between an established population of hatchery origin (stocked) and naturally produced (wild) lake trout (Salvelinus namaycush) in Lake Champlain at a range of sizes, including immature and mature fish. Fifty-six stocked and 34 wild lake trout were implanted with acoustic transmitters, including 45 transmitters with temperature and pressure (depth) sensors, to evaluate three-dimensional movement. Movement behaviours were assessed based on the number of distinct lake regions used, proportional time spent among lake regions, average daily distance travelled and depth distribution. Overall, horizontal and vertical movements were similar between stocked and wild lake trout across sizes, although individuals tended to occupy shallower depths at larger sizes. Seasonal differences in movement behaviours were observed and in some cases were dependent on origin. For all lake trout, average daily movement was greatest during fall and least during summer. Depth occupied, however, had an opposite trend, with the deepest average depths during summer and shallowest during fall and winter. The proportion of time spent among lake regions and variability in depth occupied also varied seasonally but only for wild fish, and included less time spent in individual regions and greater depth variability during fall compared to other seasons. While origin had insignificant effects in most models we evaluated, model predictions consistently suggested stocked lake trout had slightly smaller movements than wild fish. These results suggest that hatchery practices may have long-term, unintended effects on fish behaviour yet overall differences are likely subtle.
孵化场养殖是渔业管理的一项关键手段，用于补充数量减少的鱼类种群并恢复已灭绝的物种。然而，成功恢复自我维持种群的放流计划却很少见。孵化场养殖的鱼类无意间的人工选择和驯化是放流个体成功的潜在限制因素，因为所选择的行为可能不太适合自然条件。在此，我们比较了尚普兰湖中一个已建立的孵化场来源（放流）种群和自然产出（野生）的湖鳟（Salvelinus namaycush）在不同大小阶段（包括未成熟和成熟个体）的季节性移动行为。56条放流湖鳟和34条野生湖鳟被植入了声学发射器，其中45个发射器带有温度和压力（深度）传感器，以评估三维移动情况。移动行为根据所使用的不同湖区数量、在各湖区花费的比例时间、日均移动距离和深度分布来评估。总体而言，不同大小的放流湖鳟和野生湖鳟在水平和垂直移动方面相似，不过个体在较大尺寸时往往占据较浅的深度。观察到了移动行为存在季节性差异，在某些情况下还取决于来源。对于所有湖鳟来说，日均移动在秋季最大，夏季最小。然而，所占据的深度呈现相反趋势，夏季平均深度最深，秋季和冬季最浅。在各湖区花费的时间比例以及所占据深度的变异性也存在季节性变化，但仅针对野生鱼类，与其他季节相比，秋季在各个区域花费的时间更少，深度变异性更大。虽然在我们评估的大多数模型中来源的影响不显著，但模型预测始终表明放流湖鳟的移动略小于野生鱼类。这些结果表明，孵化场养殖可能对鱼类行为产生长期的、意想不到的影响，不过总体差异可能很细微。
