Field experiments were carried out from August 9 to 16, 2007 at a rocky benthic site located about 500 m (31° 53′ N, 116° 43′ W) offshore of Playa San Miguel, in the Bay of Todos Santos, 20 km north of Ensenada, Baja California, Mexico (Fig. 1). This area has a mixed semidiurnal tide.