Increase in cetacean and seabird numbers in the Canal de Ballenas during an El Nino-Southern Oscillation event

Abstract

In the Canal de Ballenas, central Gulf of California, primary productivity is based on tidal mixing and appears unaffected by ENSO events. Between the ENSO year of 1983 and the anti-ENSO year of 1985 the authors censused 4 piscivores (Bryde's whale Balaenoptera edeni; common dolphin Delphinus delphis; blue-footed booby Sula nebouxii, and brown booby S. leucoagster) and three planktivores (fin whale B. physalus; black storm petrel Oceanodroma melania; and least storm petrel O. microsoma). For all species the number of individuals sighted per hour declined by 77-94% over the 3 yr period. This suggests that during ENSO events the Canal de Ballenas may serve as a refugium of high productivity and prey abundance for these highly mobile marine animals. -from Authors