Common names
Brown Catshark.
Binomial
Apristurus brunneus.
Synonyms
Catulus brunneus.
Identification
Small body. Snout short and blunt but pointed anterior to the nares. Mouth width greater than snout length. Upper labial furrows longer than lower. Dorsal fins small. First dorsal origin approximately level with middle of pelvic fin base. First and second dorsal fins of roughly equal size, with a rounded apexes. Pectoral fins small. Anal fin long. Anal fin free rear tip reaches origin of caudal fin. Lower caudal lobe weakly defined. Dorsal coloration uniformly mid to dark brown. Fins usually have dusky or black margins.
Size
Maximum length 69cm (Flammang et al. 2008). Size at birth unknown.
Conservation Status
DATA DEFICIENT
Although the brown catshark is reported to be a relatively common bycatch in deepwater trawl fisheries, insufficient catch and biological information are available to assess its extinction risk beyond Data Deficient.
Brown Catsharks are commonly taken as bycatch in deepwater trawl fisheries, which are expanding within the range of Apristurus brunneus. They are soft bodied animals that probably have a poor post-release survivorship. Deepwater sharks tend to be slow to reproduce so there is concern that they may not be able to cope with the current catch level.
Habitat
A cold water (5-8ºC) species inhabiting rocky and sandy substrates on the continental shelf and upper slopes from 33-1298m. Usually on the sea floor but sometimes caught in midwater. Deeper in warmer climates.
Distribution
The brown catshark is confined to the eastern Pacific. From Icy Point in southeast Alaska, to the Gulf of California. It is also found in Central and South America in Panama, Ecuador, Peru, and Chile (Andrade and Pequeno 2008, Ebert et al. 2013, Bustamante et al. 2014) however, southern records may be confused with other extremely similar species from South America.
Reproduction
Oviparous. One egg per oviduct at a time. Brown catshark egg cases probably have an incubation period of two or more years (Flammang 2005). Each egg case is about 5cm long and 2.5cm wide, with long tendrils that are used to attach the egg to the reef.
Diet
The brown catshark feeds on shrimps and other crustaceans, as well as small fishes and cephalopods.
Behavior
Poorly known. In Canada, egg cases are deposited during spring and summer.
Reaction to divers
Probably easy to approach like most catsharks, but rarely if ever encountered by divers.
Diving logistics
Brown catsharks are rarely seen or caught within recreational diving limits. However, the shallowest catch record was from a trawl in 33m in the Gulf Islands in western Canada, so it is theoretically possible to see brown catsharks while scuba diving.
Similar species
Filetail Catshark Distinguished by a less laterally compressed head, and larger dorsal fins – about the size of its pectoral and anal fins and a more rounded tail with a prominent caudal notch.
Longnose Catshark Distinguished by a proportionately longer snout, large narrow nostrils and much longer (taller) gill openings.