Reproductive characteristics for the blue shark (Prionace glauca) in the North Atlantic Ocean
The blue shark (Prionace glauca) in the North Atlantic Ocean is caught in large numbers in commercial fisheries and faces the possibility of overfishing. Reproductive parameters, such as size and age at maturity, are important descriptors of life history characteristics used for understanding and managing marine organisms but have not been evaluated for the western North Atlantic Ocean since 1979. To address this gap in knowledge, we used samples from 369 female and 488 male blue sharks collected during 1971–2016 and examined whether maturity parameters have changed over time. We compared sex-specific fork length (FL) (L50) and weight (W50) at median maturity between 2 time periods (1971–1977 and 2003–2016). No evidence of change in either L50 or W50 was observed for females. Males had a statistically significant increase in both parameters; however, this increase was likely the result of differences in sample size range between the time periods. Thus, all data from 1971 through 2016 were combined to obtain new estimates of age and size at 50% maturity for both sexes. The L50 and W50 are 192.5 cm FL and 49.5 kg for male blue sharks and 190.9 cm FL and 50.1 kg for female blue sharks. These updated L50 and W50 increase reliability of data inputs for fisheries management.