海洋深層水を用いた飼育下における若齢ベニズワイの脱皮の季節性(Seasonal change in molting activity of juvenile beni-zuwai crab Chionoecetes japonicus revealed by a rearing experiment using deep-sea water)
- 標題
- 海洋深層水を用いた飼育下における若齢ベニズワイの脱皮の季節性(Seasonal change in molting activity of juvenile beni-zuwai crab Chionoecetes japonicus revealed by a rearing experiment using deep-sea water)
- 作者
- 前田 経雄(Tsuneo Maeda)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2015
- 刊名
- 水産増殖
- 卷
- 63
- 期
- 1
- 頁
- p. 105-112
- 點閱數
- 2420
摘要
若齢ベニズワイの脱皮時期を明らかにする目的で，富山湾で2003年1, 2月，2004年1月に採集された第3～8齢（甲幅約5～39 mm）の計167個体を，2005年1月まで海洋深層水を用いて水温約0.7°Cで飼育し，個体ごとの脱皮日（月日）を調査した。第4～7齢における齢期ごとの脱皮時期は7～11カ月間の比較的長期にわたって見られたが，その盛期は季節的に限られ，第4齢では8～9月，第5齢では3～4月，第6齢では10～翌1月，第7齢では8～9月であり，齢期によって異なった。齢期ごとに，脱皮の中央日を算出したところ，第4齢から第7齢の中央日はそれぞれ8月26日，4月2日，11月23日，9月9日であった。これらの中央日から第5～7齢の継続期間，すなわち脱皮間隔は，それぞれ約7.3，8.0，9.7カ月と推定された。
In order to elucidate the molting activity of juvenile beni-zuwai crab Chionoecetes japonicus, a rearing experiment was conducted using running deep-sea water from Toyama Bay, which was maintained at a temperature of 0.7±0.1°C (median±interquartile range). The molting date for individuals was examined until January 2005 for 167 crabs at 3rd-8th instars (carapace width: 5-39 mm), which were collected from Toyama Bay in January and February 2003 and January 2004. Although each molting activity for the 4th-7th instars lasted for 7-11 months, the peak of molting was limited seasonally and was different between instars (4th instar, August-September; 5th instar, March-April; 6th instar, October-January; 7th instar, August-September). The midpoint date of the molting season was defined as total of the base point date and the median of the days from the base point date to each molting date, and these were calculated as August 26th, April 2nd, November 23rd, September 9th from 4th to 7th instar, respectively. These findings suggest that the duration (intermolt period) at each instar from 5th to 7th instar is about 7.3, 8.0, and 9.7 months long, respectively.
In order to elucidate the molting activity of juvenile beni-zuwai crab Chionoecetes japonicus, a rearing experiment was conducted using running deep-sea water from Toyama Bay, which was maintained at a temperature of 0.7±0.1°C (median±interquartile range). The molting date for individuals was examined until January 2005 for 167 crabs at 3rd-8th instars (carapace width: 5-39 mm), which were collected from Toyama Bay in January and February 2003 and January 2004. Although each molting activity for the 4th-7th instars lasted for 7-11 months, the peak of molting was limited seasonally and was different between instars (4th instar, August-September; 5th instar, March-April; 6th instar, October-January; 7th instar, August-September). The midpoint date of the molting season was defined as total of the base point date and the median of the days from the base point date to each molting date, and these were calculated as August 26th, April 2nd, November 23rd, September 9th from 4th to 7th instar, respectively. These findings suggest that the duration (intermolt period) at each instar from 5th to 7th instar is about 7.3, 8.0, and 9.7 months long, respectively.