駿河湾深層水および表層海水中でのサガラメ・カジメ幼体の生長に及ぼす流速の影響(Effect of flow rate on the growth of juvenile Eisenia arborea and Ecklonia cava (Laminariales, Phaeophyceae) cultured in Suruga Bay deep and surface seawaters)
- 標題
- 駿河湾深層水および表層海水中でのサガラメ・カジメ幼体の生長に及ぼす流速の影響(Effect of flow rate on the growth of juvenile Eisenia arborea and Ecklonia cava (Laminariales, Phaeophyceae) cultured in Suruga Bay deep and surface seawaters)
- 作者
- 二村 和視, 岡本 一利, 高瀬 進(Kazumi Nimura, Kazutoshi Okamoto and Susumu Takase)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2006
- 刊名
- 海洋深層水研究
- 卷
- 7
- 期
- 2
- 頁
- P 7-11
- 點閱數
- 2474
摘要
著者らは, 先に, 駿河湾深層水 (水深397mから取水, 以下, 深層水) がサガラメとカジメの種苗生産に有効であることを明らかにし, 水温と光の影響についても報告した.本研究では, 深層水または表層海水 (水深24mから取水) を掛け流した透明パイプ内でサガラメとカジメの幼体を培養し, 0.5-9.4cm・sec-1の4段階の流速条件で生長を比較した.サガラメは約14℃ で24日間, カジメは約18℃ で16日間, いずれも自然光下で培養を行った.深層水中では, 2種の葉長の相対生長率は調べた範囲 (ただしサガラメでは9.4cm sec-1が欠測) の流速に対してほぼ一定で, サガラメで4.9-5.2% day-1, カジメで9.1-9.7% day-1となった.しかし, 表層海水中では, 流速の増加に伴い増加し [サガラメ: y=0.40Ln (x) +4.47 (r2=0.99);カジメ: y=0.84Ln (x) +7.99 (r2=0.99)], 最大でそれぞれ5.4, 9.7% day-1となった.以上, サガラメやカジメは深層水を用いれば, 流速の多少に関わらず培養できることが示唆された.
The authors previously reported the usefulness of deep seawater (DSW, known as clean, cold and nutrient-rich seawater pipelined from a depth of 397 m in Suruga Bay, central Pacific coast of Japan) in seed production of brown algae Eisenia arborea and Ecklonia cava and the effects of light intensity and water temperature on their juvenile growth. In the present study, juvenile sporophytes of the two species were cultured at four flow rates (0.5-9.4cm sec-1) of DSW and surface seawater (SSW, pipelined from a depth of 24m) in a transparent pipe to determine the best flow rate condition. The culture was conducted under the natural light condition at a water temperature of 14°C for 24 days in E. arborea and at 18°C for 16 days in E. cava. As a result, no significant difference was found in the relative growth rates (in blade length) of the two species in the examined range of flow rate (but data was not obtained at 9.4cm sec-1 in E. arborea) when cultured in DSW. However growth rates of E. arborea and E. cava increased with the flow rate in SSW [E. arborea: y = 0.40Ln (x) + 4.47 (r2 = 0.99); E. cava: y = 0.84Ln (x) + 7.99 (r2 = 0.99)], attaining each maximum, 5.4% day-1 and 9.7% day-1, respectively. These results indicate that juvenile sporophytes of E. arborea and E. cava can grow in DSW faster than in SSW regardless of the flow rate. Use of DSW may result in the decrease of unevenness of juvenile growth in the culture tank.
The authors previously reported the usefulness of deep seawater (DSW, known as clean, cold and nutrient-rich seawater pipelined from a depth of 397 m in Suruga Bay, central Pacific coast of Japan) in seed production of brown algae Eisenia arborea and Ecklonia cava and the effects of light intensity and water temperature on their juvenile growth. In the present study, juvenile sporophytes of the two species were cultured at four flow rates (0.5-9.4cm sec-1) of DSW and surface seawater (SSW, pipelined from a depth of 24m) in a transparent pipe to determine the best flow rate condition. The culture was conducted under the natural light condition at a water temperature of 14°C for 24 days in E. arborea and at 18°C for 16 days in E. cava. As a result, no significant difference was found in the relative growth rates (in blade length) of the two species in the examined range of flow rate (but data was not obtained at 9.4cm sec-1 in E. arborea) when cultured in DSW. However growth rates of E. arborea and E. cava increased with the flow rate in SSW [E. arborea: y = 0.40Ln (x) + 4.47 (r2 = 0.99); E. cava: y = 0.84Ln (x) + 7.99 (r2 = 0.99)], attaining each maximum, 5.4% day-1 and 9.7% day-1, respectively. These results indicate that juvenile sporophytes of E. arborea and E. cava can grow in DSW faster than in SSW regardless of the flow rate. Use of DSW may result in the decrease of unevenness of juvenile growth in the culture tank.