Kärgenberg Einar, Økland Finn, Thalfeldt Mart, Thorstad Eva B, Sandlund Odd Terje, Tambets Meelis
Wildlife Estonia, Tartu, Estonia.
Estonian Marine Institute, University of Tartu, Tartu, Estonia.
J Fish Biol. 2020 Oct;97(4):996-1008. doi: 10.1111/jfb.14454. Epub 2020 Sep 3.
Potamodromous fishes require safe migration routes between spawning, feeding and wintering habitats to complete their life cycle. As knowledge on asp migrations is restricted, this work investigated the movements of adult asp tagged with acoustic transmitters for 3 years in the large Peipsi-Emajõgi-Võrtsjärv lake-river system, Estonia, which is free of migration barriers. Asp showed complex migration patterns, moving between and within different waterbodies (lakes, river, tributaries) in all seasons, but with a tendency to repeat habitat use patterns between years. Lakes were mainly used for feeding during spring and summer (after spawning 65% of the fish migrated to Lake Peipsi), and more so by large fish. The majority (80-96%) of the fish spent the winter in the rivers, mostly close to their subsequent spawning area. Spawning areas were in swift-flowing waters in tributaries and the main river. The results indicate that asp may benefit from an extensive and diverse complex of habitats, and any migration barrier during any season may restrict the natural habitat use by asp. Maintenance and restoration of habitat heterogeneity and connectivity is critical to protect behaviourally diverse fish populations and increase resilience in rivers negatively impacted by various human activities.
洄游性鱼类需要在产卵、觅食和越冬栖息地之间有安全的洄游路线，以完成其生命周期。由于对欧洲鲇洄游的了解有限，这项研究在爱沙尼亚没有洄游障碍的大型派普斯湖-埃马约吉河-沃尔茨湖湖河系统中，对成年欧洲鲇佩戴声学发射器进行了3年的跟踪，以研究其洄游情况。欧洲鲇呈现出复杂的洄游模式，全年在不同水体（湖泊、河流、支流）之间及内部移动，但每年有重复栖息地利用模式的趋势。湖泊主要在春季和夏季（产卵后65%的鱼洄游到派普斯湖）用于觅食，大鱼更是如此。大多数（80%-96%）的鱼在河流中过冬，大多靠近其随后的产卵区域。产卵区域位于支流和主河的水流湍急处。结果表明，欧洲鲇可能受益于广泛多样的栖息地复合体，任何季节的洄游障碍都可能限制欧洲鲇对自然栖息地的利用。维持和恢复栖息地的异质性和连通性对于保护行为多样的鱼类种群以及增强受各种人类活动负面影响的河流的恢复力至关重要。
