Analysis of the potential geographic range of the Pacific oyster Crassostrea gigas (Thunberg, 1793) based on surface seawater temperature satellite data and climate charts: the coast of South America as a study case

Abstract

Ecological niche modeling based on surface seawater (SST) and atmospheric (AT) temperature records was used to predict the potential range of distribution of Crassostrea gigas, focusing on the South American coast as a study case. In its native range, the species maintains self-sustaining populations at thermal regimes with mean SST ranging from 14.0° to 28.9°C for the warmest month and from -1.9° to 19.8°C for the coldest month of the year. Settlement is also constrained to mean AT varying between 15° and 31°C for the warmest month and between -23° and 14°C for the coldest month of the year. Latitudinal limits for the species' distribution in South America predicted by the analysis of AT regimes were Valdivia-Chiloe Island (39.8°-42.0°S, Chile) and Pisco (13.4°S, Peru) on the Pacific coast, and San Julian port (49.3°S) (Argentina) and Garopaba-Rio Grande (28.0°-32.0°S, Brazil) on the Atlantic coast. Geographical limits of distribution predicted by analysis of SST regimes were Chiloe Island (42.0°S, Chile) and Mancora (4.1°S, Peru) on the Pacific coast, and Puerto Deseado ria (47.7°S, Argentina) and Paranaguá (25.7°S, Brazil) on the Atlantic coast. Therefore, SST regimes would expand the potential range on the Pacific coast equatorward relative to AT.