New Jersey Scuba Diving

Smooth Dogfish
Mustelus canis

Size:
to 4ft (male)
to 5 ft (female)

Habitat:
shallow coastal waters, in depths 30 ft and below.

Notes:

Smooth Dogfish are tannish-gray, slate-gray, or brown above. The lower sides and belly are white, grayish-white, or yellow. A sooty spot is often found near the tip of the upper lobe of the caudal fin. The species is distributed from New Brunswick, Canada, to Uruguay, and inhabits the bottoms of estuaries and coastal waters out to a depth of about 650 feet. During the spring and summer, most of the sharks are found in waters less than 60 feet deep.

The Smooth Dogfish Mustelus canis is one of the most common sharks along the Atlantic coast of the United States. The small gray-brown shark discarded on a pier or beach in the spring of the year is probably a Smooth Dogfish or "Smoothhound". It is a medium-sized shark reaching a maximum length of about 5 feet, although fish in the 1- to 3-foot class are more common. The species has a slender body with two dorsal fins nearly equal in size. The second dorsal fin is positioned slightly ahead of the anal fin. Other distinguishing characteristics are the narrow, catlike eyes, the large spiracle behind each eye, and the caudal fin, which has a small lower lobe.

Spawning occurs in coastal waters from May through July over most of the range. Males are sexually mature when they are 1 to 2 years old, females when they are 2 or 3. Fertilization is internal, and after a 10-month period, the female births 4 to 20 ( average 14 or 15 ) 14-inch pups. The sexes grow at different rates. Females are larger at a given age than males, and attain a larger maximum size ( 59 inches compared to 43. ) Average lengths for the sexes combined for ages 1, 5, 10, and 15 years are 16.9, 43.9, 50, and 52 inches. Smooth Dogfish use their senses of sight and smell to scavenge for prey, usually during the hours of darkness. Favorite foods are crabs, fishes, squids, clams, worms, and lobsters.

• Fishes of the Gulf of Maine