Featured Elasmobranch – Brown Catshark
Category : Featured Elasmobranch
Apristurus brunneus (Gilbert, 1892)
Family Scyliorhinidae (Catsharks)
Identification: A small slender bodied catshark with a broadly rounded snout, an internarial space about equal to the nostril length, a discontinuous supraorbital sensory canal, upper labial furrows that are longer than the lowers, relatively small gill openings, two dorsal fins set far back on the body, the first dorsal is nearly equal to or slightly smaller than the second and originating posterior to the origin of the pelvic fins. The anal fin extends nearly to the caudal base and the caudal fin upper dorsal margin lacks a crest of enlarged denticles. Coloration is a uniform brown, with the fin edges being slightly darker.
Size: Maximum reported length 69 cm. Size at birth is 7-9 cm.
Distribution: The brown catshark occurs from southeast Alaska to northern Baja California. This or a similar species is also found off Central and South America between Panama and Peru.
Habitat: A somewhat common inhabitant of the outer continental shelf and upper slope from 33-1,298 m, but most commonly found between 200-500 m. Juveniles and adolescents tend to occupy a midwater habitat between 200-300 m off the bottom and in some areas in water over 1,000 m. they seem to prefer areas where the water temperature is 430 to 480 degrees Fahrenheit.
Biology: The reproductive mode, as with most catsharks, is oviparous. Females and males both mature between 45-55 cm total length. Size at maturity varies slightly throughout its range with those from southern California (320 to 380 N) maturing at a slightly smaller total length than those from more northern ends (380 to 460 N) of its range. The egg cases once deposited on ocean floor may take up to 27 months for the embryos inside to develop prior to hatching. Their diet includes pelagic crustaceans, cephalopods, and small bony fishes.
General interest: Occasionally taken as by-catch, these sharks are too small to be of any commercial value. Studies on the reproductive biology have been carried out in recent years by researchers at the Pacific Shark Research Center.
By David A. Ebert
Pacific Shark Research Center
Moss Landing Marine Laboratories
8272 Moss Landing Road
Moss Landing, CA 95039