Critically Endangered
Narrownose smooth-hound
Mustelus schmitti
Narrownose smooth-hound is a shark or ray in the family Triakidae (order Carcharhiniformes) — Mustelus schmitti, recorded as Critically Endangered.
Appearance
M. Schmitti has gray coloration and spots on the top side of its body and a lighter gray coloration on the bottom side of its body. In addition to coloration, M. Schmitti has two dorsal fins, the first dorsal fin (on the anterior side of the body) being more prominent than the second dorsal fin (on the posterior side), both of that have exposed ceratotrichia. The exposed ceratotrichia, that are filaments of collagen creating the fin shape, cause the appearance of a thin, dark band on the dorsal fins on their posterior margins.
The total length of M. Schmitti can vary across their distribution. M. Schmitti found in Argentina showed longer body lengths than individuals closer to Uruguay.
Range and habitat
M. Schmitti is endemic to the southwestern Atlantic Ocean coast. More specifically, M. Schmitti is found on the continental shelves of the subtropical south-western Atlantic Ocean, from southern Brazil to northern Argentina, between latitudes 30° S and 44° S, at depths between 60 m to 195 m. M. Schmitti has shown ontogenetic habitat preference with distributions differing between age classes of juveniles and neonates, and the adults.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Diet and breeding
M. Schmitti is often described as an "opportunist feeder" due to their diets that include a wide range of prey but are dominated by crustaceans, fish, and polychaetes. The individuals residing in the deeper water of Río de la Plata also feed on crustaceans but consume other organisms as well, primarily fish and polychaetes.
Prey selection in this area shifts to fish as the sharks' size increases and moves into deeper water, that is typical in adults. This cycle includes migrating toward warmer areas where females can birth litters of one to ten offspring.
In crisis
M. Schmitti is considered a critically endangered species. This is due to the issue of fishing, both as a victim of bycatch and intentionally through artisanal fishing. Even so, when they are unintentionally caught as bycatch, the specific size of individuals caught is dependent on the size of the gillnets used, that differs across different areas.
To tackle this issue, specific sized gillnets are promoted to narrow down the portion of the M. Schmitti population being caught. Given the migration pattern, reproductive rate, and growth rate, M. Schmitti is particularly vulnerable to overexploitation through artisanal fishing and as victims of bycatch.
Narrownose smooth-hound is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Narrownose smooth-hound, Wikidata item Q1951864. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
