Smooth dogfish
ExploreMustelus canis
Type: fish
Status: stable
Species Guide
Smooth dogfish
Mustelus canis
Species Type: fish
Conservation Status: stable
IDENTIFICATION
The smooth dogfish goes by several names, including the dusky smoothhound. This is a relatively small shark, typically growing to a length of 3 feet long (though 5-foot long individuals are possible).
They are slender and gray above, white below. The eyes are large, oval, and closely-spaced. There is a spiracle located directly behind each eye. The mouth is small, the snout short, and the teeth are flat and blunt. The dorsal fins are similar in size with the first being slightly larger and both lack spines. The upper lobe of the tail fin is larger than the lower and deeply notched.
Distribution & Habitat
This species occurs within the western Atlantic Ocean in separate populations which can be found as far north as eastern Canada and as far south as Argentina. They inhabit continental shelf waters, from the surf zone to a depth of about 700 feet. They migrate inshore and north during the summer, south and offshore during the winter.
Diet
Smooth dogfish will eat crustaceans, squid, and bony fish. They are also opportunistic scavengers. They are generally harmless to humans. Their flat, blunt teeth are used for crushing and grinding food, rather than tearing it.
Life Cycle
Smooth dogfish mate between May and June. They are viviparous and bear 4-20 pups after a ten month gestation. The young are approximately one foot in length when born. Females reach sexual maturity in 4-5 years, while males reach sexual maturity in 2-3 years. It is an active nocturnal species which may hunt in schools. Females may live to an age of 16 years while males may live to 10.
Current Threats, Status, and Conservation
The smooth dogfish currently has no federal or New Jersey state conservation status. They are abundant and are often caught by fishermen both from shore and offshore. Because of the frequency with which they are caught, many are often intentionally killed as “junk fish” or for consuming bait intended for other fish.
Although this species appears to be stable and abundant in many portions of its range, some populations have shown a decline. Reasons for the decline include both commercial and recreational fisheries and as by-catch. Marine pollution, especially from plastics, also threatens this and many other marine species. Fortunately, its fast growth, early maturity, and relatively high rate of reproduction should enable populations to recover if allowed.
Smooth dogfish are hardy in captivity and are kept in many aquariums.
References
Compagno, Leonard, M. Dando and S. Fowler. 2005. Sharks of the World.
Text written by Michael J. Davenport in 2016.
Scientific Classification
- Kingdom: Animalia
- Phylum: Chordata
- Class: Chondrichthyes
- Order: Carcharhiniformes
- Family: Triakidae
- Genus: Mustelus
- Species: M. canis