Estimates of vital rates and population dynamics parameters of interest for porbeagle shark in the western north Atlantic and south Atlantic Ocean

We updated vital rates and population dynamics parameters for input into stock assessments of the western North Atlantic and South Atlantic Ocean porbeagle shark. These included maximum population growth rate (rmax), generation time ( A ), steepness (h), and spawning potential ratio at maximum excess recruitment (SPRMER). We used six methods to compute rmax deterministically and incorporated uncertainty in vital rates through a Leslie matrix approach. Productivity (rmax) for the western North Atlantic assuming an equally probable 1 or 2 year breeding frequency was 0.045-0.068 yr-1for the six deterministic methods. For the stochastic Leslie matrix, rmax=0.059 yr-1 (CIs=0.03–0.081), h=0.45 (0.31–0.59), A =20.1 years (17.3–21.3), and SPRMER=0.56 (0.41–0.74). The South Atlantic was data deficient and we had to use life history data from the South Pacific. Because the stochastic Leslie matrix resulted in very low or implausible values of productivity and other population parameters we recommend using results of the deterministic scenario with an annual reproductive cycle and longevity obtained through bomb radiocarbon (65 years), which yields rmax=0.059 yr-1, h=0.45, and SPRMER=0.55.