斑节对虾苗和刀额新对虾苗对低盐度适应力的研究

取体长为11mm的斑节对虾苗和刀额新对虾苗体长为6．1mm，经暂养数天后，分别在不同盐度的水中进行试验。结果表明，这两种虾苗适应低盐度十分广泛。刀额新对虾苗可比斑节对虾苗适应更低的盐度。斑节对虾苗在从盐度23．18直接降至盐度6．21时，成活率仍可达70％。当虾苗饲养在盐度18．54时，直接放水至海水盐度5．1，成活率为85％。当虾苗在从盐度25．13逐渐淡化到盐度1时，成活率仍有20％～40％。但是，考虑到体重的增重率，虾苗最佳饲养盐度为13．8。刀额新对虾苗从盐度23．18的海水直接放入盐度2以下的海水中，成活率仍有56．7％～63．3％。如果逐渐淡化海水，可在盐度＜2时正常生长。在盐度8．96左右饲养，其体重增重率最佳。上述这两种虾适于河口低盐度地区养殖。在有条件的养成场适当降低盐度，有利其生长。

Study on the Adaptability to Salinity in Penaeus monodon and Metapenaeus ensis

Two species, Penaeus monodon and Metapenaeus ensis, were cultured at various salinities. The results indicated that the ability to adapt to salinity in the two species is very broad, especially to lower salinites. Normal growth is favorable at salinities above 5. M. ensis is more adaptable than P. monodon to lower salinities, and the former even grow normally at salinities over 1, when the dilution is gradual. Based on growth rates, the optimum salinity for P. monodon is 13. 8 and M. ensis is 8. 96. Therefore, the two species are considered to be adaptable to culture in lower estuarine salinities. On some farms, the best growth rates will be obtained by reducing the salinity.