Geographical and intrapopulation variation in the diet of a threatened marine predator, Pontoporia blainvillei (Cetacea)

Diet variation can occur in geographically structured populations due to variation in prey availability. Within locations, diet may vary due to effects of season, sex, age, and individual. Nevertheless, these sources of variation are seldom considered together in dietary studies. Major efforts are underway to investigate population and ecological traits of marine organisms to set guidelines for conservation and management. Examining diet variation is a major concern when developing conservation guidelines for threatened species, especially for marine predators whose prey availability can be reduced by commercial fisheries. We analyzed diet variation at the geographical and intrapopulation levels for detecting stocks of the franciscana dolphin (Pontoporia blainvillei) within São Paulo State coast. We analyzed samples of stomach contents of individuals incidentally caught by artisanal fisheries. We investigated the geographical (Northern, Central, and Southern regions of São Paulo State ...