Effects of the "EL Niño" event on the recruitment of benthic invertebrates in Bahía Tortugas, Baja California Sur

Abstract

An evaluation of the effects of El Niño (1997-98) on the recruitment of benthic invertebrates (abalone, spiny lobster, and kelp beds) was carried out in two reefs at Bahía Tortugas on the central Pacific coast of Baja California. Density changes of juvenile abalone (Haliotis fulgens and H. corrugata), kelp (Macrocystis pyrifera and Eisenia arborea), and puerulus settlement of spiny lobster (Panulirus interruptus), before and throughout El Niño, were used to measure the impact on the recruitment of benthic populations of the rocky sublittoral. El Niño had a different effect on each species. Kelp beds were eliminated at an early stage in fall 1997, but recovered partially one year later and fully by winter 1999. Density of one-year-old abalone was reduced drastically in fall 1997. It slowly recovered throughout 1998 and 1999. During the latter period, this age group displayed high variability in length, suggesting an indirect effect of El Niño on the food supply of juvenile abalone. Density of puerulus spiny lobster settlement was positively stimulated during El Niño matching, without any time lag, the increase in mean sea level and surface temperature. We conclude that benthic communities on this part of the coast show high resilience, and their populations are adapted to recovering their structure and normal community conditions one and a half to two years after the El Niño event.