Possible factors causing the fluctuation of the recruitment of Japanese mantis shrimp Oratosquilla oratoria in Tokyo Bay [Japan]

The associations between the recruitment of the Japanese mantis shrimp Oratosquilla oratoria and environment variables were examined in Tokyo Bay. The catch data and CPUE calculated from fishermen's logbook showed abrupt decline from 1991 to 1992, and has remained low thereafter. Multiple regression analysis took relevant lag times into account suggests that the recruitment of O. oratoria is significantly related with river runoff and surface temperature at the lag of three years. Relationships between the recruitment of O. oratoria and these environmental variables are discussed.