Filetail Catshark: Parmaturus xaniurus

Family: Pentanchidae
Common name(s)

Filetail Catshark.


A small catshark with a short, rounded snout. Mouth wider than snout length. Eyes large and bluish-green when reflecting light. First dorsal origin slightly posterior to pelvic fin origin. Second dorsal origin posterior to anal fin origin. First and second dorsal fins of roughly equal size, with rounded apexes and straight posterior margins. Pectoral fins small. Pelvic and anal fins of roughly equal size; larger than dorsal fins. Lower caudal lobe has a defined apex. Dorsal coloration brown  or grey brown with no obvious markings. Fins may have dusky tips.


Maxium size 61cm. Males mature at 37-45cm. Females mature at 47-55cm.


Adults are epibenthic and found near areas of rocky vertical relief over soft mud bottoms on the outer continental shelf and upper slope at depths of 91 to 1,251 m, juveniles are mesopelagic, found around 500 m off the bottom in waters over 1,000 m deep.


The filetail catshark is found in the northeastern Pacific, from Washington State to Baja California and throughout the Sea of Cortez.

Conservation Status


The filetail catshark is not targeted by commercial fisheries or utilized for human consumption, but is known to be incidental catch in longline and bottom trawl fisheries, although no species-specific data are available.
While no species-specific management plans have been put in place, along the west coast of the United States a groundfish management plan has been implemented, and in northern and central California bottom trawl vessels have become reduced and restricted due to the development of marine protected areas. In Mexico, no management exists, however this species was assumed to be outside of the reach of artisanal gillnet and trawl fisheries. Given that groundfish fisheries within at least half of the distribution of this catshark are under management (along the west coast of the United States), that this species was among the most common chondrichthyan caught during west coast trawl surveys between 2003 and 2011, and that this species appears to be out of artisanal trawl and gillnet reach in Mexico, the Filetail Catshark is assessed as Least Concern. However, there is an urgent need for species-specific data to confirm this status, and once such data become available, this species should be reassessed as a priority.

Citations and References
Flammang, B.E., Cailliet, G.M. & Ebert, D.A. 2015. Parmaturus xaniurusThe IUCN Red List of Threatened Species 2015: e.T60231A80671960. Downloaded on 16 November 2020.


An oviparous species, laying eggcases throughout the year. More egg cases are deposited during July through September.


Feeds on pelagic crustaceans and small bony fishes. Pelagic squat lobsters (Pleuroncodes planipes) are heavily targeted.


Filetail catsharks are found on the substrate and hundreds of meters about the sea floor where they hunt for their pelagic prey. Will explore anoxic areas in search of food.

Reaction to divers

Rarely (if ever) seen by divers. Likely shy due to its small size.

Diving logistics

The minimum recorded depth of the filetail catshark is 90m, so it is unlikely that even tech divers will run into this species in the wild.
It is a long shot, but it may be possible for tech divers to see this species during the seasonal migration of pelagic squat lobsters in California, as these free-swimming crustaceans are the filetail catshark’s favorite prey. I have seen the decapod migration at approximately 40m depth off Catalina Island in August, but to be successful, divers would have to descend significantly deeper.

Similar species

Brown Catshark Distinguished by longer, more laterally depressed snout, smaller eyes, and much longer anal fin.

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