Scomber japonicus is one of the primary pelagic fish in the East China Sea and Yellow Sea and has continuedto maintain a high yield in recent years. Inter-decadal changes in the reproductive biology characteristics ofS. japonicus must be investigated to determine the cause for the continued high production under strong fishingpressure. The inter-decadal changes in reproductive stock structural characteristics, such as the fatness index, femaleto male ratio, and fork length at maturity, were evaluated based on data collected from 1054 S. japonicussamples collected during three periods from 1960 to 2012 in the East China Sea. The results show that the agestructure, dominant age group, fatness index, and the minimum and mean fork length sat maturity of there productivestocks tended to decrease with time. The 2 to 7-year age and the 2 to 5-year age groups were dominant in the1960s, where as the 1 to 4-year age and 1 to 2-year age groups were dominant in the early 21st century. Mean forklength and mean body weight decreased by 47.04 mm and 247.39 g, respectively, from the 1960s to the early 21stcentury, which were decreases of 13.98% and 44.17%, respectively. The fatness index decreased by 0.14, whichwas a decrease of 11.48%. Mean fork length at maturity in males and females decreased by 48.07 mm and 45.70 mm,respectively, which accounted for decreases of 14.30% and 13.58%, respectively. The female to male ratio wasnear 1: 1 (P>0.05), but showed an increasing trend. A large number of age-1 fish joined the reproductive stock inthe early 21st century, compared with the previous two periods, which increased the number of reproductive stocks.No significant difference in fork length at maturity was detected between males and females (P>0.05), but minimumand mean fork lengths at maturity in males were slightly larger than those in females. S. japonicus has followedsome self-adjusting mechanisms to maintain population continuity. For example, reduced age at maturityand increases in the gonadosomatic index and the percentage of females have improved relative fecundity andreduced egg size in face of increasing fishing pressure during the past 50 years. We propose three fishery managementstrategies to maintain population stability and sustain the fishery based on the long-term changes in thebiological characteristics of the S. japonicus reproductive stocks in the East China Sea. The first is to control thepelagic fishery fishing effort and establish fishing boat and net standards. The second is to set up spawning fishreserves on the main spawning grounds. Special closed fishing periods should be implemented during larval feeding.The third strategy is to implement a total allowable catch management system for S. japonicus.