Burridge L E, Haya K
Department of Fisheries and Oceans, Biological Station, St. Andrews, New Brunswick, E0G 2X0, Canada.
Ecotoxicol Environ Saf. 1997 Nov;38(2):150-4. doi: 10.1006/eesa.1997.1571.
Pesticide formulations containing pyrethrins are being used to treat salmonids for infestations of the copepod parasites Lepeophtherius salmonis and Caligus elongatus (sea lice). The acute lethality of one such formulation to four larval stages of the American lobster (Homarus americanus), a species of significant economic importance in eastern Canada, was determined. The formulation tested contained 0.06% pyrethrins and 0.6% piperonyl butoxide (a synergist). Stage I larvae (48-h LC50 = 4.42 microg/liter) were significantly less sensitive than stage II, III, or IV larvae. Stage II larvae (48-h LC50 = 2.72 microg/liter) were significantly less sensitive than Stage III or IV larvae. Stage III and IV larvae were not significantly different in their response to the pyrethrins formulation (48-h LC50 = 1.39 and 0.73 microg/liter, respectively). Most published studies using lobster larvae have reported that the earliest larval stage was the most sensitive to chemicals. The results described here indicate that the earliest larval stage is the least sensitive to the pyrethrins formulation.
含有除虫菊酯的农药制剂正被用于治疗感染了桡足类寄生虫鲑鱼虱（Lepeophtherius salmonis）和长刺鱼虱（Caligus elongatus）的鲑科鱼类。测定了其中一种制剂对美国龙虾（美洲螯龙虾，Homarus americanus）四个幼体阶段的急性致死率，美国龙虾在加拿大东部具有重要的经济意义。所测试的制剂含有0.06%的除虫菊酯和0.6%的胡椒基丁醚（一种增效剂）。第一阶段幼体（48小时半数致死浓度=4.42微克/升）的敏感性明显低于第二、第三或第四阶段幼体。第二阶段幼体（48小时半数致死浓度=2.72微克/升）的敏感性明显低于第三或第四阶段幼体。第三和第四阶段幼体对除虫菊酯制剂的反应没有显著差异（48小时半数致死浓度分别为1.39和0.73微克/升）。大多数关于龙虾幼体的已发表研究报告称，最早的幼体阶段对化学物质最敏感。这里描述的结果表明，最早幼体阶段对除虫菊酯制剂最不敏感。
