Featured Elasmobranch

February 2006

BERING SKATE

BATHYRAJA INTERRUPTA (GILL and TOWNSEND, 1897)

FAMILY ARYNCHOBATIDAE (SOFTNOSE SKATES)

Identification: A medium-sized skate with a short, flexible rostrum, and a dorsal surface uniformly covered with prickles. The ventral surface is smooth, except at the tip of the snout. This skate has 1, sometimes 2, scapular thorns on each side and 17-30 regularly spaced median tail thorns. A middorsal row of trunk thorns are mostly absence, although may be reduced on some individuals. Coloration is a dark brown to blackish dorsally, occasionally with scattered darker spots, and a white ventral surface, except for the underside of the tail which is darker.

Size: Maximum length for males is 82.5 cm and for females is 82 cm.

Distribution: The Bering skate may form a species-complex in Alaskan waters with distinct species occurring in each of the major ecosystems; Bering Sea/Aleutian Islands and Gulf of Alaska. Records of this species in Canadian waters, and further south, needs confirmation.

Habitat: The Bering skate can be found on muddy or sandy bottoms at depths of 55-1,372 m, although they are found mostly between 200-600 m in the Bering Sea.

Biology: Oviparous, with small egg cases, up to 6 cm in length, with long horns and coarse longitudinal fibers. The total length at first maturity for males is 67 cm and 70 cm for females. Their diet includes benthic invertebrates, such as crustaceans, as well as small, demersal, teleost fishes. Currently, the age, growth, and reproduction of this species is under investigated at Moss Landing Marine Laboratories. The information obtained from this study will fill important aspects in the life history of this skate.

General interest: Bering skates are commonly taken as bycatch in bottom trawl fisheries for Pacific cod, flatfish, and rockfish. However, they are of little commercial importance. Information about this skate is limited as there are many gaps in the life history of this species. Further compounding the limited data on this species is that it may represent a species complex, i.e. there may be several similar looking species co-occurring within its known range. The taxonomic status of the Bering skate is uncertain as it is sometimes placed in a separate genus, Rhinoraja. The Bering skate is also often confused with the sandpaper skate, Bathyraja kincaidii (Garman, 1908); a closely related species known to occur off Washington, Oregon, and California.

By Ashley Neway
Pacific Shark Research Center
Moss Landing Marine Laboratories
8272 Moss Landing Road, Moss Landing, CA 95039
aneway@mlml.calstate.edu