高水温期に駿河湾深層水添加により冷却養殖したアワビの成長・生残(Growth and survival of abalone in Suruga Bay deep seawater mixed. with surface seawater during the high water temperature period)
- 標題
- 高水温期に駿河湾深層水添加により冷却養殖したアワビの成長・生残(Growth and survival of abalone in Suruga Bay deep seawater mixed. with surface seawater during the high water temperature period)
- 作者
- 二村 和視, 花井 孝之, 岡本 一利, 高瀬 進(Kazumi NIMURA, Takayuki HANAI, Kazutoshi OKAMOTO, Susumu TAKASE)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2007
- 刊名
- 海洋深層水研究
- 卷
- 8
- 期
- 1
- 頁
- P 23-26
- 點閱數
- 2571
摘要
アワビ類は高水温期に摂餌量が減少し, 成長が停滞する. このため, 表層海水の水温が高水温になる時期に, 低温安定性を特徴とする駿河湾深層水を加えて水温を調整した際のアワビの成長・生残への影響について調べた. 材料には, 殻長約40mmのメガイアワビおよび養殖適種であるエゾアワビ (♂) × メガイアワビ (♀) 交雑種F1 (以下, 交雑種とする) を用い, 試験は8月から12月まで行った. 表層海水区および表層海水に水深397mから取水した駿河湾深層水を加えることで平均水温を20℃ 以下にした区 (混合海水区) を設定した. 使用した個体数は500個体前後に調整し, 各試験開始時および終了時に無作為に抽出した50個体の殻長を測定し, 日間成長率 (μmd-1) を算出した. メガイアワビを用いた試験区での平均水温は, 表層海水区で23.9 ± 2.2℃, 混合海水区で19.3 ± 1.1℃ であった. 表層海水区および混合海水区試験区の生残率および日間成長率は, それぞれ94.6, 96.8%および27, 62μmd-1であった. 交雑種を用いた試験の平均水温は, 表層海水区および混合海水区でそれぞれ22.4 ± 1.0℃ および19.6 ± 0.8℃ であった. これらの試験区の生残率および日間成長率は, それぞれ99.5, 99.8%および44, 60μmd-1であった. 以上から, アワビ陸上養殖を行う際, 表層海水に深層水を混合することで夏季においても成長が維持され, 結果的に飼育期間を短縮できると考えられた.
During a high water temperature period in summer, abalones decrease consumption of food and hardly grow in temperate waters in Japan. In this study, growth and survival rates of abalone were compared between a culture in running surface seawater (SSW) and another culture in running SSW cooled by mixing Suruga Bay deep seawater pumped from a depth of 397 m (SSW + DSW) at Shizuoka Prefectural Research Institute of Fishery from August to December in 2004 or 2005. Approximately 500 shells of Haliotis gigantea (43 mm in shell length) and an F 1-hybrid abalone (male H. discus hannai × female H. gigantea; 41 mm in shell length) were cultured in net cages (100 × 100 × 35 cm) set in tanks (5t volume) by feeding enough artificial compounds. In H. gigantea, survival rates in SSW (23.9 ± 2.2°C) and SSW + DSW (19.3 ± 1.1°C) were 94.6 and 96.8% and daily growth rates (50 samples) were 27 and 62 μm d-1, respectively. In the hybrid, survival rates in SSW (22.4 ± 1.0°C) and SSW+DSW (19.6 ± 0.8°C) were 99.5 and 99.8%, and daily growth rates (50 samples) were 44 and 60 μm d-1, respectively. Therefore, SSW + DSW surely improved growth and survival of abalone in summer and may allow us to shorten its total culture period.
During a high water temperature period in summer, abalones decrease consumption of food and hardly grow in temperate waters in Japan. In this study, growth and survival rates of abalone were compared between a culture in running surface seawater (SSW) and another culture in running SSW cooled by mixing Suruga Bay deep seawater pumped from a depth of 397 m (SSW + DSW) at Shizuoka Prefectural Research Institute of Fishery from August to December in 2004 or 2005. Approximately 500 shells of Haliotis gigantea (43 mm in shell length) and an F 1-hybrid abalone (male H. discus hannai × female H. gigantea; 41 mm in shell length) were cultured in net cages (100 × 100 × 35 cm) set in tanks (5t volume) by feeding enough artificial compounds. In H. gigantea, survival rates in SSW (23.9 ± 2.2°C) and SSW + DSW (19.3 ± 1.1°C) were 94.6 and 96.8% and daily growth rates (50 samples) were 27 and 62 μm d-1, respectively. In the hybrid, survival rates in SSW (22.4 ± 1.0°C) and SSW+DSW (19.6 ± 0.8°C) were 99.5 and 99.8%, and daily growth rates (50 samples) were 44 and 60 μm d-1, respectively. Therefore, SSW + DSW surely improved growth and survival of abalone in summer and may allow us to shorten its total culture period.