Imminent extinction of the guanay cormorant on the Atlantic South American coast: a conservation concern?

Abstract

Guanay cormorants Phalacrocorax bougainvilli are distributed mostly on the Pacific coast of Peru and northern Chile. A small population of around 50 pairs was described on the Patagonian Atlantic coast in the late 1960s. Further records have revealed a progressive decrease of this population. During 1999 we looked for guanay cormorants at those Atlantic colonies where the species was recorded in the past. Only four individuals were detected in one colony (Punta Lobería), and all of them were mated with king cormorants P. albiventer. In addition, we recorded hybrids between guanay and king cormorants mated with pure king cormorants P. atriceps. Causes of the population decline are unknown. Since guanay cormorants inhabiting the Atlantic coast could be a genetically differentiated population, we emphasize the need for molecular studies. If genetic polymorphism is detected, the capture of remnant individuals in order to constitute a genetic stock should be considered.