Salinity tolerance and early survival of F1 hatchlings crossbred between amphidromous and landlocked strains of ayu under experimental condition

• Published in: Ichthyological research 2023-11, Vol.70 (4), p.467-473
• Main Authors: Iguchi, Kei’ichiro, Takeshima, Hirohiko
• Format: Article
• Language: English
• Subjects: Animal Systematics/Taxonomy/Biogeography; Artificial seawater; Biomedical and Life Sciences; Conspecifics; Ecology; Fish; Fish populations; Freshwater & Marine Ecology; Genetic crosses; Immunological tolerance; Inland fisheries; Inland waters; Introgression; Japan; Juveniles; Lakes; Larvae; Life Sciences; Offspring; Osmotic pressure; Paternity; Plecoglossus altivelis; progeny; Restocking; Salinity; Salinity effects; Salinity tolerance; salt tolerance; Seawater; Seedlings; Survival; Transplantation; Zoology
• ISSN: 1341-8998; 1616-3915
• DOI: 10.1007/s10228-023-00905-5

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.