Mustelus schmitti, Narrownose Smoothhound

Abstract

The Narrownose Smoothhound (Mustelus schmitti) is a small (to 109 cm total length) shark that occurs in the Southwest Atlantic from Rio de Janeiro, Brazil to south of Puerto Deseado, Santa Cruz, Argentina. It inhabits the continental shelf and estuaries at depths of 2–195 m. It is captured in intense and largely unregulated commercial and artisanal demersal trawl, gillnet, and beach seine fisheries throughout its geographic range. On the southern Brazilian shelf, catches of adults in research trawl surveys declined by 90% between 1972 and 2002, equivalent to a population reduction of 88% over three generation lengths (28 years). In Uruguay, landings peaked at over 3,200 t in 1999 and have declined steadily since. This fishery was considered over-exploited by 2006. Similar levels of unmanaged exploitation are suspected to be leading to declines in Argentina. This species has a similar geographic and depth distribution to the Critically Endangered Striped Smoothhound (Mustelus fasciatus). Overall, due to the intense and largely unmanaged fishing pressure it is exposed to throughout its range, its lack of refuge at depth, and documented declines, it is suspected that the Narrownose Smoothhound has undergone a population reduction of >80% over the past three generations (28 years), and it is assessed as Critically Endangered A2bd.