1Notojima Station, National Center for Stock Enhancement, Fisheries Research Agency, Notojima, Ishikawa926-0216, 2Toyama Prefectural Fisheries Research Institute, Namerikawa, Toyama 936-8536, 3Akkeshi Station, National Center for Stock Enhancement, Fisheries Research Agency, Akkeshi, Hokkaido 088-1108, Japan
This study was conducted to investigate the ecology of hatchery-reared Japanese sandfish Arctoscopus japonicus. In April 2000, a total of 6,966 fish (mean total length 10.4 cm) were tagged and released in Nanao Bay off Ishikawa Prefecture and Toyama Bay off Toyama Prefecture. A total of 123 fish (1.8%) were recaptured over a long period of time until January 2005. Maturity (ejaculation and ovulation) was recognized in male and female recaptured fish of 2 years. Concerning the items of the recaptured fish, adult fish of 2 years and over considered as the spawning stock accounted for more than 90 percent of all those recaptured. In two releasing trials, more than half (50.8, 55.2%) of the recaptured fish remained in Toyama Bay and most of the others (33.8, 41.3%) moved northward from the release site and recaptured offshore of Niigata, Yamagata and Akita Prefectures. These results indicate that hatchery-reared sandfish released in Nanao Bay and Toyama Bay mainly remain, grow up and spawn in Toyama Bay, and some sandfish migrate northward and interchange with stock of the northern Sea of Japan or the Niigata area.