Mark-recapture experiment of Torahugu, Takifugu rubripes, at the eastern out-side of Kanmon Channel in Yamaguchi Prefecture [Japan]
2007
Matsuno, S.(Yamaguchi-ken. Fisheries Research Center, Nagato (Japan)) | Kimura, H.
In order to study the effectiveness of stock enhancement, juveniles of Torahugu, Takifugu rubripes, marked by branding and tagging method were liberated at the coast of Sanyoonoda City, the eastern out-side of Kanmon Channel, in Yamaguchi Prefecture in the summer of 2003 and 2004. The liberated fish as well as wild Torahugu were captured in adjacent areas, and statistically analyzed for natural resources and growth of the fish. The number of wild juvenile Torahugu in the survey area in July was estimated as about 800000 at most in recent years. There was no difference of growth between the liberated and wild fish in both years. However the growth of the fish was significantly different between 2003 and 2004, probably due to different feed environment between the two years. The daily growth rates in 2003 and 2004 were estimated to be 1.15mm and 1.44mm, respectively. According to these results, when the liberation of Torahugu is planned, the carrying capacity of the area must be considered, because feed environment may control the growth of the population. In addition to economies, it is also important to shorten the breeding period of the fish to maintain the natural property in the liberating fish.
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