Reproductive dynamics of striped marlin (Kajikia audax) in the central North Pacific

Abstract

Context Within the western and central North Pacific Ocean stock of striped marlin (Kajikia audax), reproductive information is lacking for the central North Pacific. Aims To derive estimates of sex-specific functional maturity ogives, eye-to-fork length at 50% maturity, reproductive phase composition, spawning season and sex ratios by sampling the Hawaii-based pelagic longline fishery. Methods Gonad histology was exclusively used to confirm sex and estimate all reproductive life history traits. Key results Females spawn in May–July; males are capable of spawning year-round. Best length at 50% maturity estimates were based on datasets restricted to the female spawning season (eye–fork length for females 152.2 cm and for males 109.0 cm). Length distributions and sex ratios are seasonally dynamic around Hawaii and differ from those in other Pacific regions. Conclusions Length-at-maturity estimates for the central North Pacific are lower than all sex-specific estimates reported from other Pacific regions. Implications The new maturity estimates will improve determinations of stock resilience and productivity in upcoming international assessments.