The Impacts of Fishing on Hermaphoditic and Treatment of Sex Change in Stock Assessments

Sex-changing fish species present unique challenges for stock assessment and management. Fishing is known to cause size at sex change to decrease and sex ratios to increasingly skew because of sex-selective fishing patterns. We show through a systematic literature review that the effects of fishing on hermaphrodite species can vary widely. Intense fishing has had no detectable effect on sex ratio and size at sex change in some stocks but a clear and dramatic impact on others. There is also substantial variation in the way stock assessments incorporate sex change. Of the 12 stock assessments of hermaphroditic fish stocks in the United States, none evaluate sex-based differences in selectivity, 10 report current sex ratio and estimate size at sex change, and only one tracks changes in both of these critical population characteristics. Despite these challenges, a global comparison of stock status suggests that the status of hermaphroditic stocks is not substantially different from that of gonochoristic species.