山陰地方における漕刺網漁業について-VI : 若狭湾におけるアカアマダイ資源量の年変動

概要

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The population size of branquillos, which was estimated from the catch statistics with sweeping trammel net, varied from 55 to 165 tons in Wakasa Bay from 1961 to 1970. To examine yearly variation in the population size, analyses were made with length and age compositions of branquillos catch in the sweeping trammel net fishery in the bay, 1961-1970.The length and age compositions indicated that the population size was greatly dependent on the abundance of 2 and 3 years old fish (19-25cm in length) and that there were predominant year classes such as 1958 and 1964. The survival (processes) of each year class could approximately be represented by an exponential function in a certain age range. The analyses of age compositions gave a density dependent reproduction curve of branquillos, although plots were found scattered to a certain extent. Further, it was found that a yearly variation in availability affected the estimation of fish number index, and hence survival rate, with the length composition of catch.
日本水産學會の論文