Spatio-temporal movement patterns of aquatic organisms drive many ecological processes. However, dams block migrations and alter the hydrologic and thermal regimes influencing movement behaviour of freshwater fishes. In North America, many recovering southern Lake Sturgeon populations occur in rivers with hydroelectric dams, but few studies have examined the impact of hydrologic alteration on their seasonal movements. We conducted a 3-year telemetry study of 96 adult and subadult Lake Sturgeon to compare their migratory responses to temperature and hydrology in adjacent regulated and unregulated tributaries of the Missouri River. Many other populations of Lake Sturgeon use tributaries primarily for spring spawning; however, in our study, Lake Sturgeon used Missouri River tributaries during 78% of the year. Differences in river size, hydrologic and thermal regimes in the regulated Osage River may have contributed to the greater year-round residency, later initiation, more frequent directional changes and longer duration of spring migrations compared to the unregulated Gasconade River. Lake Sturgeon made spring upstream migrations at temperatures of 13–19°C and elevated discharges in both rivers. However, Osage River migrants responded less to changes in discharge or temperature during spring migrations, especially those that overwintered at upstream locations. Fall tributary migrations occurred in the Osage River at rising or high discharges but were uncommon in the Gasconade River. Our identification of the influences of abiotic variables on the timing, duration and extent of Lake Sturgeon seasonal migrations can help guide management of habitat and hydrology in regulated rivers to recover migratory fishes globally.

中文翻译：

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受管制和不受管制的密苏里河支流的湖鲟季节性活动

水生生物的时空运动模式驱动着许多生态过程。然而，大坝阻碍了迁徙并改变了影响淡水鱼类运动行为的水文和热状况。在北美，许多正在恢复的南部湖鲟种群发生在有水电大坝的河流中，但很少有研究检查水文变化对其季节性运动的影响。我们对 96 只成年和亚成年湖鲟进行了为期 3 年的遥测研究，以比较它们在密苏里河受管制和不受管制的支流中对温度和水文的洄游反应。湖鲟的许多其他种群主要使用支流进行春季产卵。然而，在我们的研究中，鲟鱼湖在一年中有 78% 的时间使用密苏里河支流。河流大小的差异，与未受管制的加斯科纳德河相比，受管制的奥塞奇河中的水文和热力状况可能促成了更大的全年驻留、更晚的开始、更频繁的方向变化和更长的春季迁徙持续时间。鲟鱼湖在 13-19°C 的温度下向上游迁移，两条河流的流量都增加了。然而，在春季迁徙期间，欧塞奇河迁徙者对流量或温度变化的反应较少，尤其是那些在上游地点越冬的迁徙者。秋季支流迁移发生在欧塞奇河的上升或高流量，但在加斯科纳德河并不常见。我们确定了非生物变量对时间的影响，