Migration of Fishes in Japan

The Japanese Archipelago is unique in that it extends from the near-arctic island of Hokkaido to the subtropical southern Ryukyu Islands that are situated along the Kuroshio Current, and this latitudinal range supports a remarkable diversity of migratory fishes. These fishes include diadromous species that are anadromous and use the sea for a feeding and growth biome and freshwater for a reproductive biome (salmons and lampreys), catadromous species that use freshwater for their feeding and growth biome and the sea for a reproductive biome (freshwater eels and sculpins), freshwater amphidromous species that use both the sea and freshwater for feeding and growth biomes and freshwater for the reproductive biome (Ayu Plecoglossus altivelis , sculpins and gobies), potamodromous fishes that make relatively short migrations in freshwater, such as in Lake Biwa (cyprinids), and oceanodromous species that make migrations between their marine spawning and feeding areas (tunas, yellowtails, etc.). The geomorphology of the Japanese Archipelago and the northward flowing Kuroshio and Tsushima warm currents have likely shaped this diverse fauna of migratory fishes in both the marine waters and freshwater rivers where a relatively high percentage of species are diadromous. The diadromous species are particularly vulnerable to anthropogenic impacts of habitat loss or blockages to connectivity between the ocean and freshwater habitats and require careful considerations for conservation.