微小亚历山大藻及裸甲藻对黑鲷早期发育影响的比较

Comparison study on the effects of Alexandrium minutum and Gymnodinium sp.on development of egg and larvae of Sparus macrocephalus

采用静水实验法,温度为(20.2±2.0)℃,并保持实验用水溶解氧为饱和溶氧的60%,分别用微小亚历山大藻和裸甲藻的藻液与过滤海水按一定比例混合稀释成约30 000、15 000和7 500 cell·mL-13个浓度组,同时以过滤海水为对照组,每一个浓度组设3个平行样本,对人工养殖的黑鲷鱼卵和仔鱼进行毒性比较实验.结果表明:鱼卵孵化对微小亚历山大藻和裸甲藻2种藻液的胁迫均较为敏感,且微小亚历山大藻的毒性作用较裸甲藻弱;2种藻液对仔鱼96 h-LC50全长和体质量增长均产生一定的抑制作用,但仔鱼对裸甲藻液的敏感性更强;2种藻液对仔鱼ATPase的酶活性抑制作用差异明显,但裸甲藻的抑制作用更为突出.说明裸甲藻对黑鲷鱼卵和仔鱼的生长发育影响明显高于微小亚历山大藻.

Static bioassay tests were conducted to investigate the effects of Alexandrium minutum and Gymnodinium sp.on the growth and development of Sparus macrocephalus.The eggs of S.macrocephalus were incubated in enamel basin at different density of cells（30 000 cell·mL-1,15 000 cell·mL-1,7 500 cell·mL-1 and 0 cell·mL-1） of two planktons,at the temperature（20.2±2.0） ℃ and 60 percent of dissolved oxygen saturation.The same conditions were carried out to culture the larvae.The results showed Gymnodinium sp.was more toxic to the eggs and larvae of S.macrocephalus than A.minutum,and both species restrained the growth of body length and mass increasing of the larvae.There was significant difference in the influence of A.minutum and Gymnodinium sp.on the ATPase of the larvae of S.macrocephalus,and Gymnodinium sp.inhibited more strongly to its ATPase enzyme activities.The results above show that Gymnodinium sp.has greater impact on the early development of S.macrocephalus than A.minutum.