U.S. Geological Survey, Great Lakes Science Center, Hammond Bay Biological Station, Millersburg, MI, United States of America.
Rubenstein Ecosystem Science Laboratory, University of Vermont, Burlington, VT, United States of America.
PLoS One. 2019 Feb 6;14(2):e0211687. doi: 10.1371/journal.pone.0211687. eCollection 2019.
Timing of activity, especially for juvenile anadromous fishes undertaking long migrations can be critical for survival. River-resident larval sea lamprey metamorphose into juveniles and migrate from their larval stream habitats in fall through spring, but diel timing of this migratory behavior is not well understood. Diel activity was determined for newly metamorphosed sea lamprey using day/night net sampling and passive integrated transponder (PIT) telemetry in two natural streams and PIT telemetry in an artificial stream. Downstream migration was primarily nocturnal in all studies. All but one of 372 sea lamprey were captured during night sampling in the day/night net collections and all detections (N = 56) for the in-stream PIT telemetry occurred within a few hours after sunset. Most (81% of 48) tagged lamprey moved downstream during the first night following release and moved at speeds consistent with observed water velocities. During long-term observation of behavior in the artificial stream most sea lamprey movement occurred during the night with limited occurrence of movement during daylight hours. Understanding seasonal and diel timing of downstream migration behavior may allow more effective management of sea lamprey for both conservation and control.
活动时间，特别是对于进行长途洄游的幼年溯河洄游鱼类来说，对其生存至关重要。河生幼海七鳃鳗在秋季到春季期间从其幼鱼溪流栖息地变态为幼鱼并洄游，但这种洄游行为的昼夜时间安排尚不清楚。我们使用昼夜网采样和被动集成转发器（PIT）遥测技术在两条自然溪流和一条人工溪流中对新变态的海七鳃鳗进行了昼夜活动测定。在所有研究中，下游洄游主要在夜间进行。在昼夜网采集的夜间采样中，除了一个之外，所有 372 条海七鳃鳗都在白天被捕获，而所有的感应（N = 56）都发生在日落几个小时内。在释放后的第一个晚上，大多数（81%的 48 条）标记的七鳃鳗顺流而下，移动速度与观察到的水流速度一致。在人工溪流中对行为进行长期观察期间，大多数海七鳃鳗的活动都发生在夜间，白天的活动有限。了解下游洄游行为的季节性和昼夜时间安排可能有助于更有效地管理海七鳃鳗，以实现保护和控制的双重目标。
