不同孵化方式、培育密度和附着基对瘤背石磺人工繁育的影响

Effects of different hatching ways, cultivating densities and incubators on the artificial breeding of Onchidium struma

为提高瘤背石磺(Onchidium struma)在胚胎发育和幼虫发育过程中受精卵的孵化速率和幼虫的存活率,本试验模拟滩涂生态环境对瘤背石磺亲贝进行人工养殖,并促使其交配产卵。将采集的瘤背石磺新鲜卵块置于盐度18,水温25～26℃的水体中进行孵化。比较3种不同孵化方式对孵化速率的影响,并研究不同孔径(1.0～1.5 mm)海绵附着基和不同培育密度对幼虫存活率的影响,同时结合幼虫在各水层中分布的变化规律,探索瘤背石磺胚胎发育和幼虫发育过程的关键技术。结果显示,采用3种方式("喷淋"、"露空"和"梯笼")孵化,受精卵至出膜面盘幼虫期所需时间分别为8、6和9 d;大孔径(1.2～1.5 mm)海绵组对幼虫的附着效果较好,存活率显著高于小孔径(1.0～1.2 mm)海绵组(P<0.05),且两者均显著高于未添加附着基组(P<0.05);存活率与不同培育密度的二次多项式回归分析显示,瘤背石磺幼虫培育密度为55～61个/mL时存活率较高。上述结果表明,"露空"孵化方式能显著缩短瘤背石磺孵化所需时间;在生产过程中,幼虫培育密度以55～61个/mL为宜,面盘幼虫期投放大孔径海绵作为幼虫附着基能显著提高幼虫存活率且能明显缩短胚胎发育和幼虫发育所需时间。

Onchidium struma belongs to Mollusca, Gastropoda, Stylommatophore, which usually lives in the intertidal zone. The objective of this study was to improve the fertilized eggs hatching rate and survival rate of Onchidium struma in the process of embryonic and larvae development. In this of beaches was simulated in artificial breeding of the Onchidium struma, experiment, the ecological environment whose gonad has matured, and urge its mating and laying eggs. The gathered egg mass was put into water with temperature of 25 - 26 ℃ and salinity 18 for hatching. The effect of three hatching ways on hatching rate and the effects of cultivating densities and incubators （the aperture is 1.0 - 1.5 mm） on the survival rate of the O. struma larvae in combination with the changing rules of the larvae distribution in water to explore the key techniques of artificial breeding of O. struma. The results showed that the time from the fertilized eggs hatching to the out-membrane veliger stage required in three hatching way （＂spray＂, ＂exposure＂ and ＂ladder cage＂） was 8 d, 6 d and 9 d respectively. The incubator （sponge） has significant effect on the survival of the larvae （P〈0.05）. The larvae attachment and the survival rate of a large aperture sponge （1.2 - 1.5 mm） are significantly better than the small aperture sponge （1.0 - 1.2 mm） （P〈0.05）. An analysis of the relationship between survival rate and different cultivating densities by a second order polynomial regression sug- gested that it had the highest survival rate when the cultivating dens indicated that the ＂exposure＂ hatching way could markedly shorten lty the of larvae was 55 - 61 ind./mL. The results hatching time, and the optimal cultivating density was 55 - 61 ind./mL in the production process. In addition, it could significantly improve the survival rate of larvae and could obviously reduce the time when put the sponge into the water in the veliger stage of the embryonic development and larvae development process.