Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no-take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40 km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60–220 km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P. maculatus and 17 juvenile P. leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short-distance larval dispersal within regions (200 m to 50 km) and long-distance, multidirectional dispersal of up to ~250 km among regions. Dispersal strength declined significantly with distance, with best-fit dispersal kernels estimating median dispersal distances of ~110 km for P. maculatus and ~190 km for P. leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long-distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We dedicate this work to our friend, colleague and co-author Glenn Almany, who passed away in March 2015. We thank our field assistants Tony Adkins, Kris Boody, Lisa Boström-Einarsson, Rohan Brooker, Tom Bowling, Mike Cappo, Paul Costello, Ashton Gainsford, Naomi Gardiner, Naomi Greenham, Paul Groves, Scott Harte, Ninya Ishma, Stuart Kininmonth, Tom Mannering, Georgia McGee, Katie Munkres, Mark Priest, Justin Rizzari, Eva Salas, Tiffany Sih, Dylan Simonson, Tane Sinclair-Taylor, Maya Srinivasan, Brett Taylor, Peter Waldie, Rebecca Weeks, Michelle White, Christine Wong and John Wong. We also thank Bill Sawynok (Infofish Services) and members of the Gladstone and Keppel Bay Sportfishing Clubs for assistance with sample collection. We acknowledge the assistance provided by the Australian Institute of Marine Science (AIMS) and the crew of the R.V. Cape Ferguson. Thanks also to Peter Williams at Keppel Reef Scuba Adventures and to David Stewart and the crew of the M.V. Kalinda. We also wish to thank Dr Sami Al-Garawi, Hicham Mansour and Sadhasivam Perumal at the King Abdullah University of Science and Technology (KAUST) Bioscience Core Laboratory. This work was funded by the National Environmental Research Program (NERP) and the Australian Research Council (Linkage Grant). Additional support was provided by the ARC Centre of Excellence for Coral Reef Studies, the Australian Institute of Marine Science (AIMS) and KAUST (baseline research funds to MLB). Field sampling was conducted under Marine Parks Permit number G11/33554.1, Queensland General Fisheries Permit number 148534 and Animal Ethics Permit A1625.