A two-stage translocation strategy for improving juvenile survival of Hawaiian monk seals

We propose a two-stage translocation strategy to conserve metapopulations of endangered species. The concept takes advantage of variation in vital rates among subpopulations to increase individual fitness, improve species status, and maintain metapopulation structure for long-term resiliency. We simulate two-stage translocation scenarios for conserving the Hawaiian monk seal Monachus schauinslandi, a critically endangered species which exhibits highly variable juvenile, but consistently favorable adult, survival rates. Moving young seals from areas of lower to higher juvenile survival and subsequently returning them to their source site once they have reached an appropriate age improves population reproductive value. We present a decision framework for implementing two-stage translocation in a manner that minimizes risks while increasing the likelihood of desired outcomes. Two-stage translocation may be effective for metapopulations of other rare species which exhibit variation in vital rates among subpopulations and a life-stage bottleneck due to factors that are not amenable to in situ mitigation.