Resumen de Causes and contrasts in current and past distribution of the white shark (Lamniformes: Carcharodon carcharias) off southeastern South America
Alberto Luis Cione, María Julia Barla
The great white shark is a cosmopolitan temperate marine species which is rare in Argentina, Uruguay,and Brazil today. Several publications include the white shark as inhabiting Patagonian waters. However,there is no recent or fossil record of the white shark south of S 38° 30´ in the southwestern Atlantic. A toothfound in Quaternary sediments at Pehuencó (S 38° 56´), southern Buenos Aires province, is the southernmostoccurrence of the species in the southwestern Atlantic. The occurrence of C. carcharias in the Buenos Airesprovince is another confirmation that the Argentine biogeographic province extends to the south of the Río de laPlata. The present extremely scarce record indicates that there are not permanent living populations in theSouth American Atlantic coast but occasional transient individuals. However, the abundant fossil and archaeologicalrecord suggests that it was much more common in southwestern Atlantic during the late Pleistocene andHolocene than today. This drop in abundance is here mostly attributed to the massive extermination of pinnipedsand cetaceans during the XIXth and XXth centuries. Patagonian waters, where marine mammals are relativelyabundant even today, might be too cold for the species which is mostly encountered between 15-23°C. Besides,another important predator, the killer whale, which also feeds on marine mammals, is frequently found in thesewaters. Consequently, available evidence suggests that unrestricted hunting of pinnipeds and cetaceans alsodecimated another animal, a fish.
