Kimmel Jacob G, Buchinger Tyler J, Larson Douglas L, Baker Edward A, Zorn Troy G, Scribner Kim T, Li Weiming
Department of Fisheries and Wildlife, Michigan State University, 480 Wilson Road, East Lansing MI 48824, USA.
Michigan Department of Natural Resources, Marquette Fisheries Research Station, 484 Cherry Creek Road, Marquette, Michigan, 49855, USA.
Conserv Physiol. 2023 Jul 3;11(1):coad045. doi: 10.1093/conphys/coad045. eCollection 2023.
Many migratory fishes are thought to navigate to natal streams using olfactory cues learned during early life stages. However, direct evidence for early-life olfactory imprinting is largely limited to Pacific salmon, and other species suspected to imprint show life history traits and reproductive strategies that raise uncertainty about the generality of the salmonid-based conceptual model of olfactory imprinting in fishes. Here, we studied early-life olfactory imprinting in lake sturgeon (), which have a life cycle notably different from Pacific salmon, but are nonetheless hypothesized to home via similar mechanisms. We tested one critical prediction of the hypothesis that early-life olfactory imprinting guides natal homing in lake sturgeon: that exposure to odorants during early-life stages results in increased activity when exposed to those odorants later in life. Lake sturgeon were exposed to artificial odorants (phenethyl alcohol and morpholine) during specific developmental windows and durations (limited to the egg, free-embryo, exogenous feeding larvae and juvenile stages), and later tested as juveniles for behavioral responses to the odorants that were demonstrative of olfactory memory. Experiments revealed that lake sturgeon reared in stream water mixed with artificial odorants for as little as 7 days responded to the odorants in behavioral assays over 50 days after the initial exposure, specifically implicating the free-embryo and larval stages as critical imprinting periods. Our study provides evidence for olfactory imprinting in a non-salmonid fish species, and supports further consideration of conservation tactics such as stream-side rearing facilities that are designed to encourage olfactory imprinting to targeted streams during early life stages. Continued research on lake sturgeon can contribute to a model of olfactory imprinting that is more generalizable across diverse fish species and will inform conservation actions for one of the world's most imperiled fish taxonomic groups.
许多洄游鱼类被认为是利用在生命早期阶段学到的嗅觉线索游向出生地产卵的溪流。然而，早期嗅觉印记的直接证据在很大程度上仅限于太平洋鲑鱼，而其他疑似有印记行为的物种所表现出的生活史特征和繁殖策略，使得基于鲑科鱼类的鱼类嗅觉印记概念模型的普遍性存在不确定性。在此，我们研究了湖鲟的早期嗅觉印记，湖鲟的生命周期与太平洋鲑鱼明显不同，但仍被认为是通过类似机制归巢的。我们对早期嗅觉印记引导湖鲟归巢这一假设进行了一项关键预测测试：即在生命早期接触气味物质会导致其在生命后期再次接触这些气味物质时活动增加。湖鲟在特定的发育窗口和时间段（仅限于鱼卵、自由胚胎、外源摄食幼虫和幼鱼阶段）接触人工气味物质（苯乙醇和吗啉），之后作为幼鱼测试其对这些气味物质的行为反应，以证明嗅觉记忆。实验表明，在与人工气味物质混合的溪水中饲养仅7天的湖鲟，在初次接触后50多天的行为测试中对这些气味物质有反应，具体表明自由胚胎和幼虫阶段是关键的印记期。我们的研究为非鲑科鱼类的嗅觉印记提供了证据，并支持进一步考虑诸如在溪边设置养殖设施等保护策略，这些设施旨在鼓励鱼类在生命早期阶段对目标溪流形成嗅觉印记。对湖鲟的持续研究有助于建立一个更适用于多种鱼类的嗅觉印记模型，并为世界上最濒危的鱼类分类群体之一的保护行动提供参考。
