A simple approximation for larval retention around reefs
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Estimating larval retention at individual reefs by local scale three-dimensional flows is a significant problem for understanding, and predicting, larval dispersal. Determining larval dispersal commonly involves the use of computationally demanding and expensively calibrated/validated hydrodynamic models that resolve reef wake eddies. This study models variation in larval retention times for a range of reef shapes and circulation regimes, using a reef-scale three-dimensional hydrodynamic model. It also explores how well larval retention time can be estimated based on the “Island Wake Parameter”, a measure of the degree of flow turbulence in the wake of reefs that is a simple function of flow speed, reef dimension, and vertical diffusion. The mean residence times found in the present study (0.48–5.64 days) indicate substantial potential for self-recruitment of species whose larvae are passive, or weak swimmers, for the first several days after release. Results also reveal strong and significant relationships between the Island Wake Parameter and mean residence time, explaining 81–92% of the variability in retention among reefs across a range of unidirectional flow speeds and tidal regimes. These findings suggest that good estimates of larval retention may be obtained from relatively coarse-scale characteristics of the flow, and basic features of reef geomorphology. Such approximations may be a valuable tool for modeling connectivity and meta-population dynamics over large spatial scales, where explicitly characterizing fine-scale flows around reef requires a prohibitive amount of computation and extensive model calibration.
KeywordsResidence time Island wake parameter Larval retention Connectivity Coral reef Eddies
We are grateful to Dr. Mike Herzfeld for support running SHOC and initial ideas for the manuscript. We thank Dr. Peter Ridd for valuable comments during the development this work. Thanks to Geoff Millar and Simon Spagnol for IT support at AIMS. This research was funded by the Australian Research Council, James Cook University and the Australian Institute of Marine Science. P.C-H. received financial support from CONACyT and SEP (Mexico).
- Barton ED (2001) Island wakes. In: Encyclopedia of ocean sciences. Elsevier, pp 1397-1403Google Scholar
- Hellberg ME, Burton RS, Neigel JE, Palumbi SR (2002) Genetic assessment of connectivity among marine populations. Bull Mar Sci 70:273–290Google Scholar
- Herzfeld M, Waring JP, Margvelashvili N, Sakov P, Andrewartha J (2006) SHOC, Sparse Hydrodynamic Ocean Code V1.0 Scientific Manual, CSIRO Marine Research. http://www.emg.cmar.csiro.au/www/en/emg/software/EMS/hydrodynamics.html
- Kingsford MJ, Leis JM, Shanks A, Lindeman KC, Morgan SG, Pineda J (2002) Sensory environments, larval abilities and local self-recruitment. Bull Mar Sci 70:309–340Google Scholar
- Okubo A (1971) Oceanic diffusion diagrams. Deep-Sea Res 18:789–802Google Scholar
- Parslow JS, Herzfeld M, Hunter JR, Andrewartha JR, Sakov P, Waring J (2001) Mathematical modelling of the dispersal and fate of CES discharge from the Boyer Mill in the Upper Derwent Estuary: Results of Part B, final report CSIRO Div of Marine Research, Hobart, TAS, p 189Google Scholar
- Sponaugle S, Cowen RK, Shanks A, Morgan SG, Leis JM, Pineda J, Boehlert GW, Kingsford MJ, Lindeman KC, Grimes C, Munro JL (2002) Predicting self-recruitment in marine populations: biophysical correlates and mechanisms. Bull Mar Sci 70:341–375Google Scholar
- Strathmann RR, Hughes TR, Kuris AM, Lindeman KC, Morgan SG, Pandolfi JM, Warner RR (2002) Evolution of local recruitment and its consequences for marine populations. Bull Mar Sci 70:377–396Google Scholar
- Swearer SE, Shima JS, Hellberg ME, Thorrold SR, Jones GP, Robertson DR, Morgan SG, Selkoe KA, Ruiz GM, Warner RR (2002) Evidence of self-recruitment in demersal marine populations. Bull Mar Sci 70:251–271Google Scholar
- Wolanski E, Brinkman R, Spagnol S, McAllister F, Steinberg C, Skirving W, Deleersnijder E (2003) Merging scales in models of water circulation: Perspectives from the Great Barrier Reef. In: Lakhan (ed) Advances in coastal modelling. Elsevier Science, pp 411-429Google Scholar