Tracing the occurrence of the Critically Endangered smalltooth sawfish Pristis pectinata at its southernmost distribution in the Southwest Atlantic Ocean

Abstract

Sawfishes are the most globally threatened group of sharks, rays, and chimaeras. One of the 5 sawfish species is the Critically Endangered smalltooth sawfish Pristis pectinata. Although it is currently found in only a small portion of its historical range, this species was once distributed along tropical and subtropical coasts on both sides of the Atlantic Ocean. Its historical distribution included the Southwest Atlantic in Brazil and Argentina, with its presence in Uruguay assumed from its occurrence in neighboring countries. However, occurrence records in this region have only been compiled for Brazil. The aim of this study was to characterize the occurrence of P. pectinata in the Argentinean-Uruguayan Common Fishing Zone (AUCFZ). Quantitative sampling data revealed no sawfish specimens during 150 bottom trawl cruises and 8490 hauls (1905 in winter; 1647 in fall; 3141 in spring; 1797 in summer months) in the AUCFZ between 1981 and 2015. Nevertheless, qualitative data based on interviews (N = 275; researchers, fishing companies, fishermen, and recreational anglers) supports the occasional presence of sawfish in the AUCFZ. Five new oral reports were obtained and, although these records lack reference material, they have an associated capture year: 2 records from the 1950s, 1 record from the 1990s, and 2 records from the 2010s. Two of these records are the first for Uruguay and were reported by experienced fishermen. We conclude that the species was always a vagrant to the region, and suggest that the view of P. pectinata as extirpated from Uruguay and northern Argentina should be revisited.