大亚湾紫海胆(Anthocidaris crassispina)增殖放流苗种生长情况

Growth of Juvenile Anthocidaris crassispina Released and Enhanced in Dayawan Bay

关键词:  紫海胆  增殖放流  苗种  生长  大亚湾

Key words:  Anthocidaris crassispina  Stock enhancement  Juvenile  Growth  Dayawan Bay

摘要:

为了掌握紫海胆(Anthocidaris crassispina)苗种增殖放流后的生长和存活情况，本研究设计试验装置，于2013年9月−2014年5月，在大亚湾海域进行增殖试验。试验装置的表面积均为0.473 m2，紫海胆苗初始苗种壳径范围为3−9 mm，初始苗种数量密度梯度范围为3−25 ind/装置(6−52 ind/m2)，初始苗种重量密度梯度范围为1.48−13.32 g/m2。设3种苗种规格、各5个数量密度梯度、各3个平行试样的试验组，共45组，进行了240 d的海上试验。试验结果显示，增殖放流规格和数量密度对紫海胆苗种的存活率具有显著影响，高数量密度、低规格组死亡率高。在试验初期，壳径5−7 mm和7−9 mm两种规格紫海胆苗种的壳径特定增长率(SGR)、壳径增长率(GSD)以及壳径净增长率(NY)与增殖数量密度呈显著负相关。增殖重量密度对紫海胆的产量也有显著影响，其中，10 g/m2为紫海胆产量的临界最佳增殖重量密度。紫海胆苗种在11月到翌年3月生长速度缓慢，壳径特定增长率(SGR)较小。

Abstract:

Anthocidaris crassispina, which possesses high pharmaceutical and nutritive value, is one of the most important fishery species in the southeast China Sea. Because of continued over-fishing, the population of A. crassispina has been decreased sharply in last several years. Thus, it is urgent to take some actions to improve this situation. In order to study the growth rate and survival state of juvenile A. crassispina, we designed several experimental facilities, and threw them in Dayawan Bay to simulate the natural growing environment in the sea from September 2013 to May 2014. The superficial area of specially made experimental facilities was 0.473 m2. The diameter of shells was between 3 mm and 9 mm, and the density was between 3 ind and 25 ind per experimental facility (6 ind/m2 and 52 ind/m2), while the weight range was between 1.48 g/m2 and 13.32 g/m2. Fourty-five experimental facilities of Juvenile A. crassispina had been divided into 15 groups according to 3 different diameter of shells and 5 various densities (each group has three parallel facilities). The result indicates that the diameter of shells and density affected the death rate significantly. The highest death rate was in the group of smallest diameter of shells and lowest density. At the early stage of the culture, there is a significant negative correlation between 3 growth rates, Growth rate of Shell Diameter (GSD), Special Growth Rate of Shell Diameter (SGR) and Net Yield of Shell Diameter (NY), with density in groups whose diameter of shells is 5−7 mm or 7−9 mm. Two months after the culture, these differences disappeared. There is also a significant difference in production between different weight ranges. The highest production is in the group of the weight of 10 g/m2. From November to March in the next year, the juvenile A. crassispina grew more slowly and the GSD was lower.