美国熊本牡蛎基础群体构建及生产性能评估

Construction of basic population and performance evaluation for American Kumamoto oyster Crassostrea sikamea

为了获得优良熊本牡蛎(Crassosrea sikamea)种质资源,于2015年从美国Taylor贝类养殖公司引入熊本牡蛎,采用2种配对方式构建了核心基础群体;以中国熊本牡蛎选育群体为对照,评估了美国熊本牡蛎引种的生产性能及可行性。结果表明,美国熊本牡蛎相对于中国群体而言,表现出生长较快,商品规格比率较高,但存活力较低的特点。经过1周年养成,美国熊本牡蛎较中国群体子代壳高提高了11.48%,总重提高了48.12%。评估表明,群体来源对子代生产性能造成了显著的影响,而配对策略尚未产生显著影响。本研究发现美国熊本牡蛎在中国华南沿海具有较好的生产性能,这为熊本牡蛎种质改良提供了宝贵的繁育材料,也为华南牡蛎产业提供了一个可选择的优良品种。

The Kumamoto oyster （Crassostrea sikamea） was first identified in Ariake Bay, Kumamoto Prefecture, Japan, by Amemiya （1928） as a variety of the Japanese or Pacific oyster, Ostrea gigas var. sikamea （＂shikame＂ means ＂wrinkled＂ in Japanese）. Ahmed （1975） elevated it to species status （C. sikamea） after careful morphologi- cal analyses. Banks et al. （1993, 1994） provided genetic support for C. sikamea （Amemiya 1928） as a species dis- tinct from the closely related Pacific oyster C. gigas （Thunberg 1793）. Wang and Guo （2008） developed a simple, fast, and reliable method using multiplex PCR to identify C. sikamea and C. gigas. The Kumamoto oyster is now known to be widely distributed across East Asia, including Japan （Ariake Sea and Seto Inland Sea）, Korea （Suncheon Bay）, and China （southern China）. In Japan, Kumamoto oysters only command a small share of trade in the oyster culture industry, chiefly due to its small size. Therefore, little attention has been paid to securing aqua- culture broodstocks except for a recent endeavor to produce hatchery seedlings. However, in southern China, re- cent sharp declines in wild resources due to environmental pollution and marine reclamation has led to the devel- opment of artificial C. sikamea hatchery and culture of C. sikamea to meet demands for increased oyster yield. Kumamoto oysters were introduced from the American Taylor Shellfish Farms as exotic germplasm. A core-based group was built following two methods, and the performance traits and introduction feasibility of the oysters were evaluated in comparison with Chinese stock as the control. The American stock has faster growth, lower viability, and higher commodity rate than tile Chinese stock. After 1 year, shell heights and fresh weight of the American stock increased by 11.48% and 48.12%, respectively, compared with the Chinese stock. Stock source was the main factor affecting performance, and there was no significant effect of mating strategy on phenotypic traits. This study found that the American oyster in China has strong growth potential and provides valuable experimental material for improving the Kumamoto oyster, while supplying excellent variety for the oyster industry in southern China.