沿岸域

The present report deals with the age character, age determination and growth of the puffer Takifugu vermicularis (Temminck et Schlegel) in the Chikuzen-kai of the Sea of Japan. For the elucidation of these subjects, the authors used the vertebrae of 113 specimens collected by the Shikanoshima Set-net and 420 individuals taken from off the Shikanoshima with trawl nets, 1982. The results obtained were summarized as follow : 1) The best age character for age determination of this species was the 5th vertebral centrum among the otolith, pectoral radials, opercle, prepercle, cleithrum and vertebra. 2) The relationship between the centrum radius (Rmm) and total length of the fish (Lmm) was able to be described by the following equation R=0.0144L-0.1551 (γ= 0.904) All the radius of annual marks on the vertebral centrum were standardized by this equation. 3) By monthly change of marginal growth rate of the vertebral centrum, it was estimated that the annual mark was formed from June. 4) The relationship between the year (t) after the birth and the total length (Lt mm) after t year was estimated as follows. Lt=367(1-e^(-0.31t-0.136)) The calculated total length obtained by this equation was 132 mm in a year, 194 mm in two years, 241 mm in three years, 274 mm in four years and 299 mm in five years. 5) The size frequency distributions was analyzed by data of the total length of the puffer obtained from off the Shikanoshima. As a result, the averaged total length of the graduated group coincided nearly with the calculated total length. It seems that this species inhabiting the Chikuzen-kai migrates seasonally between the coastal and off the part in this water.