Dipturus nidarosiensis

Appearance

It is all dark brown-grey above, lacking distinct patterns. Its underparts are dark brown and often covered in blackish mucus, that separates it from some other skates in its range where adults generally have pale underparts (an exception is D. Oxyrinchus, that however can be distinguished by its narrower snout). The ventral surface is darker than the dorsal surface, and the species has a relatively short tail with 1-3 interdorsal thorns.

The Norwegian skate is very large, and can reach a total length of up to 2.3 m (7.5 ft). D. Nidarosiensis has a total length at birth of 24–28 centimetres (9.4–11.0 in).

Range and habitat

The maximum reported depth range of the Norwegian skate is from 125–1,420 metres (410–4,659 ft), though they most commonly occur between 200–1,000 metres (660–3,280 ft). Initially, its range was believed to be restricted to the Norwegian Sea and North Sea to the Bay of Biscay. It is occasionally encountered off the western coast of Ireland, and historically has been found near Rockall and in the Norwegian Deep, though recent surveys have not identified the species there.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet and breeding

At least in the Mediterranean Sea the primary prey are decapod crustaceans, followed by bony fish, while cephalopods, small elasmobranchs and polychaetes occasionally are consumed. Larger Norwegian skates have been noted to feed on larger fish species.

The egg case consists in a very large capsule with a long rectangular shape and pointed horns at the corners, deposited on sandy and muddy bottoms. The egg cases are very large and measure 18–26 centimetres (7.1–10.2 in) long and 9.5–12 centimetres (3.7–4.7 in) wide.

In crisis

The Norwegian skate is listed on the IUCN Red List as endangered because of increased pressures upon populations as a result of targeted fishing of sharks and rays and an estimated population reduction of over 50% across the past three generations.

Dipturus nidarosiensis is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Dipturus nidarosiensis, Wikidata item Q3767741. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.