不同环境因素对三疣梭子蟹“科甬1号”(Portunus trituberculatus)仔蟹蜕壳的影响

OPTIMAL CONDITIONS FOR PORTUNUS TRITUBERCULATUS “KEYONG 1” MOLTING

为探究三疣梭子蟹"科甬1号"仔蟹最佳蜕壳环境条件,先采用单因素变量实验设计方法,选取温度、盐度、光照时长、p H和底质五种环境因素,分析其对"科甬1号"仔蟹蜕壳的影响。温度组设置17、20、23和26°C,盐度组设置10、15、25和35,光照时长设置0、12和24h光照组,p H组设置6.0、7.5、8.0、8.5和10.0,底质设置有沙和无沙组。实验结果表明,温度组20°C时仔蟹存活率和蜕壳率最高,但蜕壳所需时间最长,26°C时蜕壳起始最早,所需时间最短,但存活率较低;盐度组中,15和25仔蟹存活率和蜕壳率最高;p H组中,7.5、8.0和8.5仔蟹存活率和蜕壳率最高;有沙组仔蟹存活率显著高于无沙组;而光照时长实验组结果差异不显著(P>0.05)。综上所述,得到单因素条件下"科甬1号"仔蟹最佳环境条件:温度20—23°C、盐度15—25、正常日周期光照、p H 7.5—8.5,有沙环境中。利用正交设计实验方法,研究温度、盐度、底质3个因素对"科甬1号"仔蟹蜕壳的影响,并构建多元线性回归模型。结果得到"科甬1号"仔蟹最佳环境条件:温度26°C、盐度25,需要有沙环境,并且拟合得到其日存活率线性回归模型以及日蜕壳率线性回归模型。

To explore the best environmental requirements for juvenile of Portunus trituberculatus ＂Keyong 1＂ molting, a single-and multi-factor experiments were designed. In the single-factor design, five factors： temperature, salinity, lighting, p H, and sediment bedding were tested. Temperature ranged 17 to 26°C in increment of 3°C; salinity 10, 15, 25, and 35; lighting hours 0, 12, and 24; p H 6.0, 7.5, 8.0, 8.5, 10.0; and with and without sandy bottom. The results showed that in the temperature group, the highest survival and molting rates were at 20°C, but the time for molting was longer; the earliest and least time molting group was 26°C, but the survival rate was lower. In the salinity group, the survival and molting rate of 15 and 25 were higher than other groups. In the p H group, 7.5, 8.0 and 8.5 were better than at p H 6.0 group. Sandy bottom was significantly better. The length of lighting had no significant difference（P〉0.05）. Therefore, in overall, the optimal conditions for the single-factor experiment were 20—23°C, salinity 15—25, normal lighting hours, p H 7.5—8.5, and sandy bottom. In multi-factor orthogonal experiment, with three factors were considered： temperature, salinity, and sediment, from which the optimal conditions turned to be 26°C, salinity 25, and with full sandy bottom. In addition, the multiple linear regression models for daily survival rate and daily molting rate were established.