Article ID: 23-040
Icefish (Salangichthys microdon) fishery was once carried out in inner Tokyo Bay. However, during the period from the 1950s to the 1960s when environmental deterioration such as water pollution and shallow water reduction progressed rapidly, icefish catch in Tokyo Bay dropped sharply, and the fish became extinct in the 1960s. In February 2021, and February and March 2022, a total of 8 adult S. microdon individuals and 321 eggs were collected in the Tama River estuary, inner Tokyo Bay. This is the first record of its existence in almost 60 years in Tokyo Bay, suggesting that S. microdon is reproducing in the Tama River estuary. Attempts to determine the origin of S. microdon collected in the Tama River estuary by mitochondrial DNA D-loop analysis were unsuccessful due to the haplotypes identified either not occurring in populations elsewhere in Japan or being common to multiple populations.
