Narrowfin smooth-hound

12/17/2017

Narrowfin smoothhound (Mustelus norrisi) specimen. Photo © George Burgess

The narrowfin smooth-hound (Mustelus norrisi) is a slender shark with large oval eyes that look down on the world over a pointed snout. They are a gray colour on top, that fades to a white colour beneath and sport long pectoral fins and an asymmetrical caudal (tail) fin.

The genus name Mustelus is derived from the Latin "mustela" meaning weasel. Reaching a total weight of 13.8 kg (30.8 lbs) and 1.1 m (3.6 ft), they don’t really seem weasel-like to us. Maybe it’s because of their slender shape, and that they tend to be an average size of 30 inches (75 cm) for males and about 35 inches (90 cm) for females. Maturity occurs in the males around 58 cm (23 in) and females at 65 cm (26 inc) total length.

Narrowfin smooth-hounds prefer the muddy bottoms of the shallow bays in the western Atlantic Ocean. Found from Florida and the Gulf of Mexico to Venezuela and southern Brazil. They are common off the western coast of Florida, observed in the sandy depths of 3-4 m (10-14 ft); they have been recorded as deep as 80 m (264 ft), though!

These sharks prefer a diet of crabs, shrimp, and small bony fish. And like many sharks, they are a host to the parasites… specifically, the parasitic copepod Perissopus dentatus, which are found on the edges of their fins.

They are a viviparous species, and birthing season is thought to start in the late water and extend into early spring. Live birth follows this gestation period and anywhere from 7-14 pups can be born. Pups tend to be around 30 cm (12 in) in length when born.

Throughout their range, there is a small commercial fishery for narrowfin smooth-hounds. They are often taken in fishing nets close to shore. But, little is known about their population health and therefore the IUCN has assessed them as Data Deficient (DD).

Interested in learning more? So are we!

glossary

Bays: A a body of water connected to an ocean or lake, formed by an indentation of the shoreline.
Commercial fishery: The activity of catching fish and other seafood for profit.
Genus: A group of organisms ranking above a species and below a family.
Gestation: The period in which a fetus develops, beginning with fertilization and ends at birth.
IUCN: International Union for Conservation of Nature.
Pectoral fins: Fins located behind the gills on either side.
Pup: Give birth to baby sharks (pups).
Pups: Baby sharks.

Viviparous: Eggs hatch inside the female's body and the babies are fed by a placenta which transfers nourishment from the mother to the babies (via an umbilical cord which is connected to the baby shark between the pectoral fins).