Modeling to aid in the planning for reintroduction of Mediterranean monk seals

We simulated the reintroduction of Mediterranean monk seal Monachus monachus individuals to create new populations using the Cabo Blanco colony (Western Sahara/Mauritania) as the source population. We evaluated potential negative impacts of removing weaned pups on population growth in the Cabo Blanco population and projected a range of plausible outcomes for reintroduced populations under 4 vital rate scenarios. Lifetables of simulated reintroduced populations were parameterized with published survival and reproductive rate estimates from the 2 extant monk seal populations in the eastern Atlantic: Cabo Blanco and Madeira. Two scenarios simulated enhanced neonatal survival to represent potentially higher survival of pups born on open beaches at reintroduction sites compared to the relatively low observed survival of pups born in caves at Cabo Blanco and Madeira. Reintroduction scenarios simulated the translocation of 6 weaned pups per year (4 females and 2 males) for 5 yr from Cabo Blanco to a reintroduction site, and both populations were subsequently projected an additional 5 yr. Simulations indicated that this level of removal would have relatively minor effects on the Cabo Blanco population, which could theoretically sustain considerably more removals and continue increasing in abundance. All simulated reintroduced populations were extant after the 10 yr projections, and the median of an aggregate distribution of final abundance from all scenarios was 27 seals (5 and 95 percentiles 15 and 52 seals, respectively). Our results support the viability of establishing new monk seal populations without causing undue harm to the Cabo Blanco colony.