Reproductive Success in Fish Stocks Can Be Reproduced by Environmental Factors Alone

This study showed that reproductive successes (RPS) in fish stocks could be reproduced using only environmental factors. As the environmental factors, the monthly Arctic oscillation index and Pacific decadal oscillation were used. The RPS of 12 stocks harvested around Japan were reproduced. The results were as follows: the fitness between observed and reproduced RPS, and the number of the independent variables necessary for reproducing the RPS differed by stock. However, the fluctuations of RPS could be reproduced using only the environmental factors. These results support the validity of the mechanism proposed by Sakuramoto regarding the factors that drive the fluctuation in RPS. That is, the fluctuation in RPS occurs due to conditions determined by environmental factors, and is not a density-dependent effect.