Martín Enrique Hernández Rivas

Fish larvae off the northwestern coast of the Baja California Peninsula, Mexico

The structure of the larval fish assemblage of the northwestern Pacific coast of Mexico is analyzed from zooplankton samples taken between 1998 and 2000 off northern and southern Baja California Peninsula. The 198 fish taxa identified reflected the faunal complexity reported previously for the area. Adult distribution patterns and reproductive behavior, added to the environmental seasonality and bathymetric characteristics of the coast, explained differences in the larval fish assemblage. Larvae of meso- and bathypelagics Vinciguerria lucetia, Diogenichthys laternatus, and Triphoturus mexicanus were the most abundant year round. Larvae of commercially important species, such as Engraulis mordax , Sardinops sagax , Merluccius productus, and Trachurus symmetricus, were also abundant during winter and spring, depending on the year and surveyed region. Adult distribution patterns and reproductive behavior, intra- and interannual environmental variability, and bathymetric characteristics of the coast all likely contributed to the differences in the larval fish community through space and time. For example, the abundance of temperate species in northern Baja California was relatively low when warm-water El Nino conditions prevailed in 1998 but increased during the cool-water La Nina period in 1999 and 2000. The results enhance knowledge of the community dynamics of fishes in an ecologically complex and commercially important region.