報告書番号

U00045

タイトル（和文）

循環濾過システムによるヒラメの生産 --雌化種苗の成長と黒化防止技術の検討--

タイトル（英文）

Studies on production of Japanese flounder in closed recirculating aquaculture system -Growth rate of feminized seedlings and preventing hypermelanosis-

概要 （図表や脚注は「報告書全文」に掲載しております）

循環濾過システムを用いたヒラメ養殖の生産性向上を図るために、雌化種苗の成長速度と黒化防止技術について検討した。1. 2gの雌化種苗を市販の配合飼料で336日間飼育した結果、平均体重706gに成長した。従来の通常種苗の飼育結果に比べて、成長は約50％速く、この結果をもとに試算したヒラメ1kgの生産費用（電気代、種苗代、飼料代)は約10％低減した。2. ４種の砂敷設水槽でヒラメを飼育した結果、飼育槽底面から上方に均一に水流が発生する水槽で砂の偏りがなく水質も良好に維持された。砂敷設水槽で飼育したヒラメを定期的に砂なし水槽に移して商品サイズまで飼育した結果、砂敷設期間が長いほど黒化程度は軽減される傾向がみられた。生産期間終了時まで砂敷設水槽で飼育することによって、飼育密度を低下させる必要があるもののほとんど黒化のないヒラメの生産が可能と考えられた。

概要 （英文）

Rearing experiment was carried out in a closed recirculation system to estimate the growth rate of feminized seedlings of Japanese flounder under the optimum culture conditions. In addition, to develop practical techniques for preventing the hypermelanosis in the blind side of Japanese flounder, performance of four different culture tanks with sand bottom was compared in terms of water quality, fish growth and coloration. Effect of rearing period in the tank with sand bottom on hypermelanosis was also examined by transferring fish to another tank without sand.1. Fish grew from 2g to 706g in mean body weight for 336 days fed on commercial pellet diet with a good survival rate (84%) and a desirable feed conversion efficiency (99%). The growth rate of fish was 50% higher than that of the previous study, and that led to the reduction of operation cost by 10%. 2. Based on the analysis of water quality, fish growth and degree of hypermelanosis, a tank with upwelling flow through sand was considered superior to the others. Prolonged rearing period in the tank with bottom sand resulted in decreasing pigmented area in the blind side. Fish cultured in tank with sand bottom through the experimental period showed little pigmented area in the blind side by keeping in low density for any fish submergible in sand.

報告者

キーワード