Round Skate

Rajella fyllae

Description

The round skate closely resembles the little skate and especially the winter skate; however, it is distinguished from both these species by its noticeably longer, plain coloured tail, especially in the young, as well as the number of series of teeth in the upper jaw (30-38 rows). The teeth of the round skate are blunt, conical and cusped. Adults typically have thorn-like spines extending along the whole mid-dorsal belt of the disc and along the upper surface of the tail, although some lack spines mid-back immediately posterior to the shoulder region. On others, additional large thorns may by present over the shoulder region, around the eye orbits, and/or in 2 or 3 irregular rows between the eyes and on the snout. In young round skate, the outer posterior margins of the pectorals are smooth; however, the anterior margins become noticeably more thorny with age. On females, a patch of large thorns also develops on the inner posterior portion of the pectorals. The pelvics are thorn-free, but have tiny spines on their upper surface. The round skate has two dorsal fins confluent at their bases, and a caudal membrane confluent with the second dorsal. The pelvics are bilobed, with anterior lobes resembling fingers. In mature males, the claspers extend halfway from axils of the pelvics to the first dorsal. Colouration in the round skate varies from ash gray to chocolate brown dorsally, and from white to gray ventrally. Sooty patches are present on the underside of both the pelvics and the rear of pectorals.

Size

The round skate grows to a maximum total length of 53 cm.

Range

In the western Atlantic, the round skate ranges from Davis Strait off west Greenland southward to the slopes off Nova Scotia and Georges Bank; however, captures of the round skate in Canadian Atlantic waters are seldom reported. This species is more frequently found in the eastern Atlantic, ranging from Iceland and the Barents Sea to waters off Norway and Denmark.

Habitat

Exploratory trawling operations have captured round skate offshore from LaHave to Browns banks in depths of 530 - 1097 m.

Life History

Unknown

Diet

The round skate apparently preys on small crustaceans.

Reproduction

The egg capsules of the round skate vary in length from 33 to 44 mm, and are 26 mm wide. The processes of collected egg capsules are often damaged.

Interaction with people

Captures of the round skate in Canadian Atlantic waters are seldom reported. This species is not economically important.