The ayu, Plecoglossus altivelis, with an amphidromous life migrating between the sea and streams, is a commercially important fish for the inland fisheries of Japan. Despite intensive transplantation, seedlings originating from non-native population landlocked in the Biwa Lake have been less contributable to stock recovery. In fact, no apparent evidence of introgression from the released fish to the native population has been obtained. We hypothesized that the parental property from the landlocked strain would give some disadvantages to the offspring against saline osmotic pressure during their early life in the sea. The acute performance of newly hatched larvae in 180% artificial seawater at 26°C was evaluated by the parental combinations of amphidromous and landlocked strains. As a result, hatchlings from amphidromous parents lived longer than those from landlocked parents, whereas outbred hatchlings showed no difference in their survival period between landlocked and amphidromous paternities. Hatchlings from amphidromous parents lived longer than outbred half-sibs with landlocked paternity, while hatchlings from landlocked parents lived shorter than outbred half-sibs with amphidromous paternity. Reduced salinity tolerance in the landlocked population was proved to be paternally inherited, which can explain the disappearance of hybridized lineage through the failure in the early survival. When supplementing for the purpose of stock enhancement, it is important to consider matching exotic conspecifics with native populations.

香鱼，Plecoglossus altivelis两栖动物，在海洋和溪流之间迁徙，是日本内陆渔业的重要商业鱼类。尽管进行了密集移植，但来自琵琶湖内陆非本地种群的幼苗对种群恢复的贡献较小。事实上，没有获得从释放的鱼到本地种群的基因渗入的明显证据。我们假设来自内陆菌株的亲本特性会给后代在海洋早期生活中抵抗盐水渗透压带来一些不利条件。通过两栖和内陆菌株的亲本组合评估新孵化幼虫在 26°C 180% 人工海水中的急性表现。因此，两栖父母的幼龟比内陆父母的幼龟寿命更长，而近亲繁殖的幼龟在内陆和两栖亲本之间的存活期没有差异。两栖父母的幼崽比具有内陆父亲的近交半同胞活得更长，而内陆父母的幼崽比具有两性父亲的远系半同胞活得短。内陆种群的耐盐性降低被证明是父系遗传，这可以通过早期存活的失败来解释杂交谱系的消失。在以种群增强为目的进行补充时，重要的是要考虑将外来同种与本地种群相匹配。两栖父母的幼崽比具有内陆父亲的近交半同胞活得更长，而内陆父母的幼崽比具有两性父亲的远系半同胞活得短。内陆种群的耐盐性降低被证明是父系遗传，这可以通过早期存活的失败来解释杂交谱系的消失。在以种群增强为目的进行补充时，重要的是要考虑将外来同种与本地种群相匹配。两栖父母的幼崽比具有内陆父亲的近交半同胞活得更长，而内陆父母的幼崽比具有两性父亲的远系半同胞活得短。内陆种群的耐盐性降低被证明是父系遗传，这可以通过早期存活的失败来解释杂交谱系的消失。在以种群增强为目的进行补充时，重要的是要考虑将外来同种与本地种群相匹配。这可以通过早期生存的失败来解释杂交谱系的消失。在以种群增强为目的进行补充时，重要的是要考虑将外来同种与本地种群相匹配。这可以通过早期生存的失败来解释杂交谱系的消失。在以种群增强为目的进行补充时，重要的是要考虑将外来同种与本地种群相匹配。