Critically Endangered
Humpback smooth-hound
Mustelus whitneyi
Humpback smooth-hound is a shark or ray in the family Triakidae (order Carcharhiniformes) — Mustelus whitneyi, recorded as Critically Endangered.
Appearance
It has a sturdy body with a moderately long, broad, sharply angled snout and large eyes, set widely apart. The first dorsal fin is approximately triangular and the trailing edge is fringed with bare, dark-coloured collagen rods known as ceratotrichia. The caudal peduncle is short and the lower lobe of the tail fin is hardly curved in adults.
The humpback smooth-hound is a small shark growing to a length of up to 68 cm (27 in) in total length for males and 74–87 cm (29–34 in) for females, with a maximum size of 119 cm (47 in). Humpback smooth-hound sharks are small sharks, reaching a maximum size of 118 cm (46 in) in total length.
Range and habitat
The humpback smooth-hound is found in the southeastern Pacific Ocean off the coast of Peru and Chile, between 1°N and 45°S. Although, the humpback smooth-hound is found within this range. It is rarely found in Chile, and mainly concentrated in Peru. Its depth range is between 16 and 211 m (50 and 690 ft) but it is most common between 70 and 100 m (230 and 330 ft).
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Diet
Humpback smooth-hound sharks feed on a variety of organisms in both the benthic and pelagic coastal ecosystems. The main components of their diet include: bivalves, cephalopods, gastropods, and teleosts.
First being that these sharks regulate prey dynamics and populations through predation. Secondly, these sharks modify and influence prey behavior and physiology.
In crisis
The threats currently causing population decline to humpback smooth-hound sharks surround issues with local fisheries and management. The Peruvian fisheries are the main threat to the population decline through directly removing these sharks and indirectly through bycatch. The unsustainable harvest causing population decline is shown in the Peruvian gillnet fisheries and the trawl fisheries in Ecuador that the Humpback is mainly caught as bycatch, and discarded.
Along with the spotted houndshark (Triakis maculata) and the speckled smooth-hound (Mustelus mento), it is known as "tollo" in its local fisheries, and of the three species it is the humpback smooth-hound that is the main target of the tollo fishery in Peru, that masks the true catch of humpback smooth-hound causing more individuals to be unsustainably removed. This is because this requirement does not protect the mature individuals that reproductively contribute to the population size and growth.
Humpback 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 Humpback smooth-hound, Wikidata item Q1951887. 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.
