Canadian Journal of Fisheries and Aquatic Sciences, Volume 78, Issue 2, Page 184-192, February 2021.
Certain spawning areas of the critically endangered Lake Saimaa landlocked Atlantic salmon (Salmo salar m. sebago) have been recently restored by excavator- and helicopter-scattered gravel, but the success of applied methodologies has remained open. Here, we monitored the spawning-related movements and redds occurrence of transported semi-wild and hatchery-reared salmon in the restored River Ala-Koitajoki, eastern Finland, using radiotelemetry and snorkeling. Nearly all fish accepted the newly restored spawning habitats in the river that maintains a low flow rate (only 4 m3·s−1). The movements of females released up to 2 weeks before spawning time were restricted mainly to the closest rapids from the release site, and most of the movements were directed downstream. Semi-wild and hatchery background fish exhibited similar mobility, which was more variable among males. A majority of redds were found in restored areas, and both helicopter- and excavator-scattered gravels were accepted as spawning substrates. Our results indicate that natural reproduction of the studied landlocked salmon population can be successfully returned to its original spawning river by restoration of habitats and transfer of spawners.

中文翻译：

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在新恢复的河流栖息地中运输内陆大西洋鲑鱼的产卵季节运动

《加拿大渔业和水生科学杂志》，第78卷，第2期，第184-192页，2021年2月。
极度濒危的塞马湖内陆大西洋鲑鱼（Salmo salar m。sebago）的某些产卵区最近已通过挖掘机和直升机散布的砾石得以恢复，但应用方法学的成功仍未揭晓。在这里，我们使用无线电遥测法和浮潜监测了恢复的芬兰东部阿拉-科伊塔基基河中与产卵有关的运动，并检测了运输的半野生和孵化场饲养的鲑鱼的发生。几乎所有鱼类都接受了河中新恢复的产卵栖息地，该产卵区维持低流速（仅4 m3·s-1）。在产卵时间前两周释放的雌性运动主要限于离释放点最近的急流，并且大多数运动都指向下游。半野生和孵化场背景鱼类的迁移率相似，男性之间的差异更大。在恢复的地区发现了大部分赤泥，直升机和挖掘机散布的砾石均被视为产卵基质。我们的结果表明，所研究的内陆鲑鱼种群的自然繁殖可通过栖息地的恢复和产卵者的转移而成功地返回其原始产卵河。