Environmental change at Ostra base Camp, a Peruvian Pre-ceramic site

A sample of vertebrate remains from Ostra Base Camp, a Middle Pre-ceramic s ite on the north-central coast of Peru occupied between 6250-5450 BP, conta ins an estimated 144 individuals, of which 53% are typical of warm-tropical regimes and 30% are typical of warm-temperate regimes or the Peru Current. These percentages are substantially different from those reported for Earl y, Middle, and Late Pre-ceramic collections from sites further south. They are also different from those reported for Alto Salaverry, a nearby Late Pr e-ceramic site. The Ostra fishing strategy took advantage of a coastal reso urce that was lost between the time Ostra was abandoned and Alto Salaverry occupied. The hypothesis that this is due to change in the marine environme nt is supported by multiple lines of evidence.