钦州茅尾海沙井采苗区牡蛎幼虫数量变动的调查分析

【目的】了解钦州茅尾海沙井采苗区牡蛎幼虫数量的变动情况,旨在提高牡蛎采苗效果。【方法】对钦州茅尾海沙井采苗区海水水温、盐度、pH等环境因子和牡蛎幼虫数量等指标进行监测,配合天气、潮汐、牡蛎性腺成熟度分析,探讨牡蛎幼虫出现高峰期与这些因素的关系。【结果】2011年5~7月钦州茅尾海沙井采苗区牡蛎亲贝出现1次繁殖高峰期（6月25日~7月3日）,繁殖高峰期出现时海区水温和盐度大幅下降,水温平均下降幅度约3.0℃,盐度平均下降幅度4.0‰~8.0‰,pH平均降幅0.97;监测期间海区牡蛎幼虫数量出现5次峰值,分别是5月21日、6月17日、7月1日、7月12日和7月18日,对应的牡蛎幼虫数量分别是2.87×104、2.13×104、1.94×104、11.94×104和1.69×104个/m3,且0.5m水层的幼虫数量较2.0m水层多。成熟牡蛎亲贝数量、精卵排放时间和排放量、潮汐海流是造成幼虫数量变动的原因。【结论】钦州茅尾海牡蛎幼虫数量的变化与海区牡蛎亲贝性腺成熟度及海区环境因子变化直接相关。

Quantity dynamic of oyster larvae in Shajing, Maowei Sea of Qinzhou Gulf

[Objective]The present study was conducted to learn the oyster larvae quantity dynamic in Shajing, Maowei Sea of Qinzhou Gulf in order to improve the effect of oysters collecting. [Method]The gonad maturity was identified and the oyster larvae quantity was calculated in Shajing, Maowei Sea of Qinzhou Gulf while the data of water temperature, salinity, pH and the weather condition were collected. [Result]The results showed that one breeding peak of mature oys- ters in Shajing was observed from 25 June to 3 July in 2011 when the water temperature （down 3.0~C）, salinity and pH （down 0.97） of seawater （down 4.0%0-8.0%0） decreased sharply. Five hatching peaks appeared on 21 May, 17 June, 1 July, 12 July and 18 July, respectively. The oyster larvae quantity of the above dates was 2.87x104, 2.13x104, 1.94x104, 11.94x104 and 1.69~104/m3, respectively. Oyster larva preferred to gather in the depth of 0.5 m than 2：0 m. The larva quantity dynamic was affected by the quantity of mature oysters, its hatch time and hatch quantity as well as the tide and ocean current. [Conclusion]The oyster larvae quantity dynamic in Maowei Sea is directly related to the gonadal maturity of mature oysters and the environmental factor in sea area.