海洋深層水と表層海水で飼育されたニジマスOncorhynchus mykissの生残と成長および成熟(Survival, growth, and maturity of the rainbow trout Oncorhynchus mykiss reared in deep seawater and surface seawater)
- 標題
- 海洋深層水と表層海水で飼育されたニジマスOncorhynchus mykissの生残と成長および成熟(Survival, growth, and maturity of the rainbow trout Oncorhynchus mykiss reared in deep seawater and surface seawater)
- 作者
- 野田 浩之, 岡本 一利, 岡田 裕史, 高木 毅(Hiroyuki NODA, Kazutoshi OKAMOTO, Hiroshi OKADA, Tsuyoshi TAKAGI)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2010
- 刊名
- 海洋深層水研究
- 卷
- 11
- 期
- 1
- 頁
- P 1-11
- 點閱數
- 2556
摘要
淡水で養成されたニジマス (体重93±38g) を, 2006年11月から駿河湾の水深687mから取水し15℃に加温した深層水 (以下, 深層水A区) で52尾, 水温無調整の表層海水 (12～16℃, 以下, 表層海水区) で51尾飼育した. 2007年4月までの日間成長率と生残率は両区で同様な値を示した. 2007年6月から, 深層水A区生残魚10尾 (体重671±541g) と, 淡水で養成後3ケ月間無加温 (7℃) の深層水で飼育したニジマス10尾 (体重337±87g, 以下, 深層水B区) を水温15℃の深層水で, 表層海水区生残魚6尾 (体重883±520g) を水温無調整の表層海水でそれぞれ飼育した. 表層海水区は7月下旬までに全て死亡した. 深層水A区とB区は2007年11月の体重が1.96±0.95kg, 1.29±0.75kgとなり, 成熟率は71%と29%であった. さらに深層水B区では2008年4月に体重3.42kgに成長した未成熟個体があった. これにより深層水をニジマスの適水温に加温することによって大型魚の生産が可能なことが確かめられた.
We investigated the survival, growth, and maturity of the rainbow trout Oncorhynchus mykiss reared in deep seawater (DSW) and surface seawater (SSW) pumped from depths of 687 m and 24 m, from Suruga Bay. From November 2006 to April 2007, 52 and 51 fishes (average body weight, 90 g and 96 g, respectively) were reared in heated DSW at a temperature of 15°C and in SSW at natural temperature (12-16°C). As a result, the growth rates of the fishes reared in heated DSW and SSW, were 1.1% and 1.2% per day, respectively, and the survival rates were 48% and 41%, respectively. From February to April 2007, 32 fishes (average body weight, 378 g) were reared in DSW at natural temperature (7°C). The growth rate was 0.0% per day, and the survival rates was 88%. From June 2007, 10 fishes that survived in heated DSW (average body weight, 671 g) and DSW at natural temperature (average body weight, 377 g) were reared in heated DSW (15°C). In November 2007, the average body weight of these fishes was 1.96 kg and 1.29 kg, respectively, and their maturity rates were 71% and 29%, respectively. The fresh meat of mature female fishes was vermilion in color, but that of mature male fishes was a pale beige color. In April 2008, the maximum body weight of fish that survived in DSW at natural temperature was 3.42 kg before maturation. From June 2007, 6 fishes that survived in SSW (average body weight, 883 g) were reared in SSW. However, all the fishes died by the end of July. Although the techniques for restraining the maturation of fishes need to be improved, these findings demonstrate the possibility of rearing large rainbow trout by using DSW.
We investigated the survival, growth, and maturity of the rainbow trout Oncorhynchus mykiss reared in deep seawater (DSW) and surface seawater (SSW) pumped from depths of 687 m and 24 m, from Suruga Bay. From November 2006 to April 2007, 52 and 51 fishes (average body weight, 90 g and 96 g, respectively) were reared in heated DSW at a temperature of 15°C and in SSW at natural temperature (12-16°C). As a result, the growth rates of the fishes reared in heated DSW and SSW, were 1.1% and 1.2% per day, respectively, and the survival rates were 48% and 41%, respectively. From February to April 2007, 32 fishes (average body weight, 378 g) were reared in DSW at natural temperature (7°C). The growth rate was 0.0% per day, and the survival rates was 88%. From June 2007, 10 fishes that survived in heated DSW (average body weight, 671 g) and DSW at natural temperature (average body weight, 377 g) were reared in heated DSW (15°C). In November 2007, the average body weight of these fishes was 1.96 kg and 1.29 kg, respectively, and their maturity rates were 71% and 29%, respectively. The fresh meat of mature female fishes was vermilion in color, but that of mature male fishes was a pale beige color. In April 2008, the maximum body weight of fish that survived in DSW at natural temperature was 3.42 kg before maturation. From June 2007, 6 fishes that survived in SSW (average body weight, 883 g) were reared in SSW. However, all the fishes died by the end of July. Although the techniques for restraining the maturation of fishes need to be improved, these findings demonstrate the possibility of rearing large rainbow trout by using DSW.