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October Elasmobranch of the Month: Narrowfin Smooth-Hound Shark

Narrowfin Smoothhound Shark

(Mustelus norrisi)

Author: Linda Weiss




Key Features/Appearance

The narrowfin smooth-hound, also known as the Florida smooth-hound, is gray to grayish-brown on top and cream to white underneath. The body shape is slender and elongated. The head is narrow and short with a noticeable spiracle located behind each eye. The first dorsal fin is located behind the small pectoral fins. Both dorsal fins are relatively large to the animal’s body size. The second dorsal fin is only slightly smaller than the first. All of the fins, excluding the pectoral fins, on this shark species are rounded at the tips. The caudal fin has two lobes, with the upper lobe significantly longer than the lower. The upper lobe has a notch near the end, resulting in the tip being wider than the rest of the lobe. The mouth is long and contains similarly shaped teeth in both the upper and lower jaws. The teeth are short with small, stumpy cusps. The narrowfin smooth hound’s average size is 90 cm (35 inches) for females and 75 cm (30 inches) for males. The maximum known size for this species is 110 cm (3.6 ft) and 13.8 kg (30.8 lbs).





Habitat and Distribution

The narrowfin smooth hound shark resides in the western Atlantic Ocean including both coasts of Florida, the Gulf of Mexico from Venezuela to Brazil. Off the west coast of Florida is where this shark is most common. This shark inhabits the waters over continental shelves as well as in shallow bays with muddy and sandy bottoms at depths of 3-4 m (10-14 ft). The deepest recorded depth for this species is 88 m (290ft).

Diet

Diet consists of small bony fish, shrimp and crabs.

Reproduction

Reproduction is viviparous, where embryos develop inside the female nourished by a yolk sac, followed by a yolk sac placenta. Approximately 7 -14 live pups are born per litter. Each pup measures approximately 30 cm (12 inches) long.

Status

The IUCN Red List of Threatened Species currently lists the narrowfin smooth-hound shark as Near Threatened, with a decreasing population trend.

Threats

The narrowfin smooth-hound shark’s natural predators include larger sharks such as the great hammerhead, the blacktip, and dusky. They are targeted by the commercial fishing industry, and like many other shark species, they are also caught as bycatch.

References

Florida Museum of Natural History

https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/mustelus-norrisi/

Mexican-fish.com

https://mexican-fish.com/florida-smoothhound/

Planet Shark Divers

https://planetsharkdivers.com/narrowfin-smoothhound-or-florida-smoothhound/

Sharkwater.com

https://www.sharkwater.com/shark-database/sharks/narrow-fin-smooth-hound/

The IUCN Red List of Threatened Species

Carlson, J., Charvet, P., Blanco-Parra, MP, Briones Bell-lloch, A., Cardenosa, D., Derrick, D., Espinoza, E., Morales-Saldaña, J.M., Naranjo-Elizondo, B., Pacoureau, N., Pérez Jiménez, J.C., Schneider, E.V.C., Simpson, N.J., Talwar, B.S. & Pollom, R. 2021. Mustelus norrisi. The IUCN Red List of Threatened Species 2021: e.T161518A890179. https://www.iucnredlist.org/species/161518/890179. Downloaded on 12 October 2021.

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