イシダイ卵仔稚に対する有機リン系殺虫剤の急性毒性
スポンサーリンク
概要
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The toxicity of organophosphorous insecticides on each developmental stage of marine fishes whichis little known, needs to be examined. This study was made to clarify the acute toxicity of MEP and diazinon, most typical organophosphorous insecticides used in Japan, on each developmental stage of eggs, larvae, and juveniles of Oplegnathus fasciatus which is one of the most important cultured fish in Japan. Developmental stages were divided into the following 11 stages which were checked only at the beginning of each experiment. Stage A (egg stage), stage B-C (prelarval stage), stage D-F (postlarval stage), and stage G-K (juvenile stage). Twentyfour hours TLm of MEP were as follows, 2.4-4.2ppm on stage A-C, 0.145ppm on stage D, and 1.25-2.30ppm on stage E-K. However those of diazinon were 3.2-6.7ppm on stage A-C, and settled down remarkably to 0.0175-0.03 ppm on stage D-K. The abnormality of body form and color and reaction was observed often in lower concentration than twentyfour hours TLm. Especially very poor growth was obvious on the fish which were exposed to MEP and diazinon for 44 hours from stage A. For example. total length of larvae in 3.2ppm of MEP was about 1/2, and of diazinon was about 4/5 normal one. These specific effects of insecticides on various develop-mental stages are considered to vary with their organogenesis and the change of drug metabolism in relation to their development. So it is necessary to purse further studies on these phenomena.