海洋深層水を用いた陸上蓄養によるエゾパフンウニ成熟抑制の試み(Control of maturation in Strongylocentrotus intermedius by stock-culturing in land-based tank using cold deep seawater)
- 標題
- 海洋深層水を用いた陸上蓄養によるエゾパフンウニ成熟抑制の試み(Control of maturation in Strongylocentrotus intermedius by stock-culturing in land-based tank using cold deep seawater)
- 作者
- 渡邉 徹, 山石 秀樹, 石亀 正則, 山下 和則, 藤田 大介(Tohru WATANABE, Hideki YAMAISHI, Masanori ISHIGAME, Kazunori YAMASHITA, Daisuke FUJITA)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2008
- 刊名
- 海洋深層水研究
- 卷
- 9
- 期
- 2
- 頁
- P 83-88
- 點閱數
- 2628
摘要
羅臼町でエゾパフンウニの禁漁期 (7～9月, 産卵期で生殖巣が崩れやすいが観光客が最も多い) の出荷の可能性を検討するため, 2003～2004年, 循環冷却で2～4℃ を保った海洋深層水で蓄養し成熟抑制を試みた. 実験は0.5トン水槽で行い, 給餌蓄養区, 無給餌蓄養区および天然ウニの生殖巣の状態を2週間毎に5段階 (I～V) で評価した. 2003 (2004) 年, 最も商品価値の高い皿期は蓄養開始時の6月25日 (5月11日) に約 (47) 70%で, 天然ウニは7月23日 (8月17日), 給餌蓄養区は8月20日 (9月14日), 無給餌蓄養区は8月20日 (8月17日) に10%以下になった.7月23日 (8月17日) のIII期出現率は給餌蓄養区で約27 (35) %, 無給餌蓄養区で約40 (10) %であった.III期生殖巣の官能検査 (2004年のみ) では各蓄養区とも7月6日 (蓄養56日後) まで, 食味, 外見とも「普通」以上の評価を得た.
At Rausu Town, northeast of Hokkaido, collection of a high-priced edible sea urchin Strongylocentrotus intermedius is prohibited for resource conservation during the spawning season from July to September. Furthermore, the removed maturing gonads are not good for commercial use because they easily ‘melt’ (collapsed). However, the urchin gonad is a potential natural food product particularly in the summer season in which most abundant tourists visit the town in a year. During summers in 2003 and 2004, maturation control was tried by culturing the collectedsea urchins in land-based tank (0.5 ton in volume) using deep seawater (DSW) colder than surface seawater (SSW). In June 2003, half of the sea urchins (>50 mm in diameter, N = 240 in June 2003) were fed with kelp, while the others were keptunfed. Gonads of fed, unfed and wild sea urchins were biweekly evaluated using standard criteria comprised of 5 stages (I to V). The deep seawater was pumped from a depth of 218 m, 1.4 km off Chienbetsu Fishing Port and the water temperature was kept between 2 and 4°C by circulating and chilling. In 2003 (2004), the most valuable gonad stage III accounted for 47 (70) % at the commencement of stock-cultured on June 25th (May 11 th) and lowered below 10% on August 20th (September 14th) in fed andon August 20th (August 17th) in unfed sea urchins. On July 23rd (August 17th), when gonads lowered below 10% in wild urchins, the ratio ofstage III accounted for 27 (35) % in fed and 40 (10) % in unfed sea urchins. In asensory test conducted in 2004, gonads in stage III of both fed andunfed sea urchins marked fine scores (higher than middle among five ranks) on taste and outlook till July 6th (stock-cultured for 56days).
At Rausu Town, northeast of Hokkaido, collection of a high-priced edible sea urchin Strongylocentrotus intermedius is prohibited for resource conservation during the spawning season from July to September. Furthermore, the removed maturing gonads are not good for commercial use because they easily ‘melt’ (collapsed). However, the urchin gonad is a potential natural food product particularly in the summer season in which most abundant tourists visit the town in a year. During summers in 2003 and 2004, maturation control was tried by culturing the collectedsea urchins in land-based tank (0.5 ton in volume) using deep seawater (DSW) colder than surface seawater (SSW). In June 2003, half of the sea urchins (>50 mm in diameter, N = 240 in June 2003) were fed with kelp, while the others were keptunfed. Gonads of fed, unfed and wild sea urchins were biweekly evaluated using standard criteria comprised of 5 stages (I to V). The deep seawater was pumped from a depth of 218 m, 1.4 km off Chienbetsu Fishing Port and the water temperature was kept between 2 and 4°C by circulating and chilling. In 2003 (2004), the most valuable gonad stage III accounted for 47 (70) % at the commencement of stock-cultured on June 25th (May 11 th) and lowered below 10% on August 20th (September 14th) in fed andon August 20th (August 17th) in unfed sea urchins. On July 23rd (August 17th), when gonads lowered below 10% in wild urchins, the ratio ofstage III accounted for 27 (35) % in fed and 40 (10) % in unfed sea urchins. In asensory test conducted in 2004, gonads in stage III of both fed andunfed sea urchins marked fine scores (higher than middle among five ranks) on taste and outlook till July 6th (stock-cultured for 56days).