Field experiments of iridium marking for red sea bream in Shijiki bay [Japan]
1991
Kato, M. (National Research Inst. of Fisheries Science, tokyo (Japan)) | Sudo, H. | Azeta, M. | Matsumiya, Y.
Iridium (Ir) marked young red sea bream, 50,000 and 40,000 in number, were released in Shijiki Bay, Nagasaki Prefecture, in 1983 and 1984, respectively. Ir were detected in scale samples by activation analysis. Number of recovered Ir marked fish was 589 in 1983 year-class and 606 in 1984 year-class, respectively. Average Ir contents decreased from 5.4-8.0 to 0.03-0.04ppm during 14-16 months after marking. Using recovery data, total mortality coefficient (z) was estimated to be 0.007 per day, fishing mortality coefficient (F) 0.001 and natural mortality coefficient including escapement (M) 0.006. Because of the goodness of physical characteristics for activation analysis, Ir marking could be easily used for young red sea bream in large number and for long period of time more than two years
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