Nagasaki Prefectural Institute of Fisheries, Nagasaki 851-2213, Japan
This study was conducted to examine the effects of release time, release size, release site, quality of seeds, CPUE of young-of-the-year and water temperature of the habitat on the growth of hatchery-produced ocellate puffer Takifugu rubripes released in Ariake Sound. The effects of seven factors on the fluctuations of the total length at recapture on November 1 (Y) of 23 release groups of seeds released based on the data of mark-recapture experiments from 1991 to 1995 and from 2000 to 2002 were examined by multiple regression analysis. The factors were as follows: the date of release in July (X1), total length at release (X2), release site (X3), CPUE (X5) and average surface water temperature of the habitat in July and August (X6) and in September and October (X7). The relationship of total length to these factors was follows:
Y=-1.14X1+0.49X2-6.03X3+0.54X5-2.60X6+1.87X7+211.69
The regression was significant at the 1% level. The calculated values of the total length follow the trend of fluctuations of the observed values. Thus, it is concluded that is necessary to release hatchery-produced ocellate puffer early in July and at a large size in Isahaya Bay and the innermost area of Ariake Sound to maximize the total length at recruitment.