Study on the biological characteristics and status of common mackerel (Scomber japonicus Houttuyn) fishery in the East China Sea region

According to the data obtained from the fishery resources monitoring in the East China Sea region during 1960 - 1961, 1973 - 1975, 1982 - 1986, and 1999 - 2002, the biological characteristic dynamics of common mackerel Scomber japonicus, such as population structure, growth and mortality, were analyzed. The results indicated that the younger and miniaturization of population structure have been quite distinct after 40 years of exploitation since the 1960s; the average fork length and the average body weight decreased from 343.14mm to 193.66mm, and from 588.79g to 96.89mm, respectively. Species intrinsic dynamical feature has changed, the growth parameter (K) increased from 0.22 to 0.81; the asymptotic fork length decreased from 486.84 to 367.50mm, the growth point of inflecxion changed from 4.48 years to 1.27 years. Although the yield of common mackerel maintained at higher level, the population was already in overfishing situation.