Movement and growth of tagged hatchery-reared Japanese flounder Paralichthys olivaceus in the Sohya waters off northern Hokkaido [Japan]
2001
Imai, Y. (Hokkaido. Wakkanai Fisheries Experiment Station (Japan)) | Yoshimura, K. | Kiyokawa, S.
To examine movement and growth, 120,000 hatchery-reared Japanese flounder Paralichthys olivaceus were tagged and released in the Sohya waters, the Sea of Japan and the Okhotsk Sea, off northern Hokkaido in September and October 1996-1999. Most recovery was recorded around the release locations within one year after release, and there the recovery continued over 3 years post-release. Also the area south of the release location one year or more after release. The distribution of flounder tended to expand toward the south. The flounder recovery concentrated from May to December, about 1.5 and 2.5 year after release, and the number of recaptuerd fish in 1996-1998 were 40-66% of the total number except in 1999, respectively. About 63-80% of each the total recovery in 1998 and 1999, under 2 years till return, were recaptured around the release locations. A few fish was recaptuerd off Ishikari, Shiribeshi, Hiyama, Oshima subpref. and Aomori pref.. In both the Sohya and the northern Rumoi waters the flounder was recaptured mainly with the gill nets or the set nets. The flounder was thought to grow rapidly during June to November after 300 days post-release, and not to grow in other months. The tagged flounder released in 1998 was 4-6cm larger in the total length than fish in 1996 and 1997 during the period 1 -2 year after release. It was no appeared the growth of tagged flounder is associated with the release locations.
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