Fishing and Mating: Effects of Exploitation on Black Sea Bass and Other Sex-Changing Species

Incorporating mating strategy into stock assessments is crucial if management plans are to be successful, especially for sex-changing fishes. Black sea bass (Centropristis striata, BSB) are commercially and recreationally important along the eastern coast of the US. They present unique management challenges because they are protogynous hermaphrodites (female to male sex change), with male fish on average larger than female fish. Size limits result in disproportionately high fishing mortality on males, potentially skewing the sex ratio. A meta-analysis of previous research on BSB and other sex-changing species revealed that high exploitation rates on protogynous species result in strongly skewed sex ratios, with male proportions in the population decreasing by as much as 20%. The length at sex change also decreased by as much as 35% of total body length in heavily fished populations. Using a mark-recapture study off the coast of New Jersey, we examined size and sex selectivity of BSB. Commercial pots selected higher proportions of males compared to recreational hook and line gear, indicating differential fishing mortality on sex. Fishing uniquely affects the population dynamics of sex-changing species and successful management must account for such dynamics.