“EL NIÑO OSCILACIÓN DEL SUR” Y ESTADO DE SALUD DE LAS IGUANAS MARINAS (Amblyrhynchus cristatus) EN GALÁPAGOS

Abstract

El Niño / Southern Oscillation (ENSO) affects biological components by its oceanic–atmospheric interaction in the tropical Pacific ocean. For Galápagos marine iguanas (Amblyrhynchus cristatus Bell, 1825) scientific studies propose a negative impact. Charles Darwin Foundation, in order to acquire long term data, has established a permanent monitoring project in an area of Santa Cruz Island. This area has 6.1 km of coastal land (61 sampling stations), from Punta Núñez (SE of the island) to Charles Darwin Research Station dock.This research shows the health state of the marine iguana population from this zone, considering six levels from 0 to 5 (healthy to dead), comparing ENSO (1997-98) and Post ENSO (2000-01) periods. Their differences and relation to health levels and environmental conditions (rain, superficial sea temperature and air temperature) were determined. Results showed significant differences (z0.05=0.4477; P<0.0001) in the health level of the marine iguana population between these periods, although health levels were not directly related (r<0.426) to environmental conditions. But if anomalous environmental conditions are maintained, a direct relationship (r=0.624) is found. Health state diminishing was notorious after sixth months with superficial sea temperature higher than 23°C (Post ENSO average), and recovering was noticed after an equal period of normal conditions.Key words: Amblyrhynchus cristatus, ENSO effect, health state, sea superficial temperature, Galapagos.