MEPS 318:19-29 (2006)  -  doi:10.3354/meps318019

Larval accumulation in the lee of a small headland: implications for the design of marine reserves

Amber J. Mace, Steven G. Morgan*

Bodega Marine Laboratory, University of California at Davis, PO Box 247, Bodega Bay, California 94923, USA
*Corresponding author. Email:

ABSTRACT: Oceanic currents and larval accumulation potentially have large impacts on the choice of locations for marine reserves. Larval settlement of benthic invertebrates was greater in the lee than on the windward side of a small headland during the height of upwelling in central California during 2001 and 2002. Strong upwelling during the study was indicated by mean seasonal Bakun indices of 149 to 176 m3 s–1 per 100 m of coastline in 2001–2002. Weekly sampling of near-surface and nearbottom settlement in the lee of Bodega Head from August 2000 to September 2001 revealed that most larvae of 7 crab taxa settled during spring and summer, which coincides with the upwelling season. Comparison of sites in the protected (lee) and exposed (windward) sides of the headland (2 sites each) during the peak settlement season in 2001 showed that most larvae settled in the lee of the headland, including 91% of crabs, 89% of barnacles, and 80% of mussels in weekly samples. During 2002, weekly sampling at 1 protected and 1 exposed site also demonstrated that most settlement occurred in the lee of the headland, including 74% of crabs, 82% of barnacles, and 65% of mussels. Crabs settled mostly at the surface, whereas barnacles and mussels primarily settled near the bottom, indicating that postlarvae in both surface and bottom waters accumulate in the lee of the headland. Larval accumulation zones should be included in networks of marine reserves to supply adult populations with propagules in recruitment-limited upwelling regions.

KEY WORDS: Larval retention · Larval dispersal · Headland eddy · Recirculation · Marine reserve · Meroplankton

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