Effect of El Niño-Southern Oscillation on population dynamic of Scartichthys viridis in the central Chile coast

Abstract

The intertidal zone has space-time variability; the fish present adaptations to these changes. Durante El Niño-Oscilación del Sur phenomenon (ENSO), variation in sea surface temperature (SST) and productivity, affect somatic growth and abundance of fish. Scartichthys viridis is the most abundant fish; SST and productivity would give its population dynamics. The objectives are to: describe the temporal dynamics of Chile's intertidal fish community, examine their relationship with ENSO; calibrate and validate a mathematical model that represents the population dynamics of S. viridis and ENSO effect; and to quantify and characterize the effects of SST and productivity during ENSO on the population dynamics of S. viridis and determine their relative importance, experimentally. Results indicated that ENSO affects assemblage. The population dynamics of S. viridis were influenced by food, El Niño y La Niña events, and SST. In the experiment, individuals presented greater RNA:DNA ratio at higher temperature. ENSO affects the assemblage and population. Experimentally, at low temperatures, food is important. ENSO affects fish from the intertidal. The tidepool, with its characteristics, would explain the differences between them.