Understanding larval connectivity patterns in exploited fishes is a fundamental prerequisite for developing effective management strategies and assessing the vulnerability of a fishery to recruitment overfishing and localised extinction. To date, however, researchers have not considered how regional variations in fishing pressure also influence recruitment. We used genetic parentage analyses and modelling to infer the dispersal patterns of bumphead parrotfish Bolbometopon muricatum larvae in the Kia fishing grounds, Isabel Province, Solomon Islands. We then extrapolated our Kia dispersal model to a regional scale by mapping the available nursery and adult habitat for B. muricatum in six regions in the western Solomon Islands, and estimated the relative abundance of adult B. muricatum populations in each of these regions based on available adult habitat and historical and current fishing pressure. Parentage analysis identified 67 juveniles that were the offspring of parents sampled in the Kia fishing grounds. A fitted larval dispersal kernel predicted that 50% of larvae settled within 30 km of their parents, and 95% settled within 85 km of their parents. After accounting for unsampled adults, our model predicted that 34% of recruitment to the Kia fishery was spawned locally. Extrapolating the spatial resolution of the model revealed that a high proportion of the larvae recruiting into the Kia fishing grounds came from nearby regions that had abundant adult populations. Other islands in the archipelago provided few recruits to the Kia fishing grounds, reflecting the greater distances to these islands and lower adult abundances in some regions. Synthesis and applications. This study shows how recruitment into a coral reef fishery is influenced by larval dispersal patterns and regional variations in historical fishing pressure. The scales of larval connectivity observed for bumphead parrotfish indicate that recruitment overfishing is unlikely if there are lightly exploited reefs up to 85 km away from a heavily fished region, and that small (
KAUST Repository Item: Exported on 2021-10-05
Acknowledgements: We thank the Kia House of Chiefs, the Kia district spearfishers, Isabel Provincial Government and Solomon Islands Ministry of Fisheries and Marine Resources for supporting and granting permission for this work. We thank W. Dolava, M. Giningele, P. Kame, A. Kokoe, H. Kokoe and M. Vaka for assisting with data collection. Assistance with genetic sequencing was provided by the Bioscience Core Laboratory at the King Abdullah University of Science and Technology (KAUST). We thank Emilie Stump for drawing the graphical abstract used in the online version of this manuscript. We acknowledge financial support from the Australian Research Council (DE160101141) and KAUST (baseline research funds to M.L.B.). This work is dedicated to the memory of the late Chief Leslie Miki.