Norrgård J R, Bergman E, Schmitz M, Greenberg L A
Department of Biology, Karlstad University, 651 88 Karlstad, Sweden.
J Fish Biol. 2014 Oct;85(4):1060-73. doi: 10.1111/jfb.12522.
The migratory behaviour of hatchery-reared landlocked Atlantic salmon Salmo salar raised under three different feeding regimes was monitored through the lower part of the River Klarälven, Sweden. The smolts were implanted with acoustic transmitters and released into the River Klarälven, 25 km upstream of the outlet in Lake Vänern. Early mature males, which had matured the previous autumn, were also tagged and released. To monitor migration of the fish, acoustic receivers were deployed along the migratory route. The proportion of S. salar that reached Lake Vänern was significantly greater for fish fed fat-reduced feed than for fish given rations with higher fat content, regardless of ration size. Fish from the early mature male group remained in the river to a greater extent than fish from the three feeding regimes. Smolt status (degree of silvering), as visually assessed, did not differ among the feeding regime groups, and moreover, fully-silvered fish, regardless of feeding regime, migrated faster and had a greater migration success than fish with less developed smolt characteristics. Also, successful migrants had a lower condition factor than unsuccessful ones. These results indicate that the migration success of hatchery-reared S. smolts released to the wild can be enhanced by relatively simple changes in feeding regimes and by matching stocking time with smolt development.
在瑞典克拉尔älven河下游，对在三种不同投喂方式下饲养的孵化场养殖的内陆大西洋鲑（Salmo salar）的洄游行为进行了监测。将幼鲑植入声学发射器，然后放流于韦纳恩湖出水口上游25公里处的克拉尔älven河中。前一年秋季已成熟的早熟雄性个体也进行了标记并放流。为监测鱼类的洄游情况，在洄游路线上部署了声学接收器。无论投喂量大小，投喂脂肪含量降低饲料的鱼到达韦纳恩湖的比例显著高于投喂高脂肪含量饲料的鱼。早熟雄性组的鱼比三种投喂方式组的鱼在河中停留的时间更长。通过视觉评估，各投喂方式组之间的幼鲑状态（银色程度）没有差异，此外，无论投喂方式如何，完全银色的鱼比幼鲑特征发育较差的鱼洄游速度更快且洄游成功率更高。而且，成功洄游的鱼的肥满度低于未成功的鱼。这些结果表明，通过相对简单的投喂方式改变以及使放流时间与幼鲑发育相匹配，可以提高放流到野外的孵化场养殖的鲑幼鱼的洄游成功率。
