Fish larvae as indicator species of interannual environmental variability in a subtropical transition area off the Baja California peninsula

The aim of this work was to determine if the variation patterns in the abundance of dominant species of fish larvae in the transition zone off Bahía Sebastián Vizcaíno, Mexico, could be used as indicators of interannual environmental variability, and how larval fish assemblages respond to this environmental variability during the period 1997–2013. With the 16 years of plankton data in the southern region of the California Current System, anomaly curves of larval abundance were calculated, from which the temporal abundance patterns of the dominant fish larvae of the mesopelagic, epipelagic and demersal environments were obtained. Classification and ordination analyses were carried out to obtain the larval fish assemblages as well as their relations with environmental variables (sea surface temperature, surface salinity, concentration of Chlorophyll-a and zooplanktonic volume) and climatic indexes (ONI, MEI, PDO and NPGO). Results showed a high positive correlation between the mesopelagic abundance with MEI and PDO indices, demonstrating their affinity with warm oceanic waters, while there were not statistically significant correlation between the climatic indexes and the epipelagic (Sardinops sagax and Engraulis mordax) or demersal species (Synodus lucioceps). The interannual variability of the abundance of three dominant mesopelagic species (Vinciguerria lucetia, Diogenichthys laternatus and Cyclothone signata) show that these species had a clearer response to environmental variability than epipelagic and demersal species. Trends in the abundance of mesopelagic species larvae and their high correlation values with the environmental variables used, demonstrate their potential as indicators of environmental change of the pelagic ecosystem in the transitional area off Bahía Sebastián Vizcaíno.