Black dogfish to the clade formed by the granular dogfish ("C. granulatum") and combtooth dogfish ("C. nigrum"). The black dogfish is a common species, with a wide but discontinuous distribution in the temperate waters of the Atlantic Ocean; its range abuts, but does not extend into, the Arctic Ocean. In the northeast, it occurs from Iceland to Sierra Leone, including the Faroe Islands, southern Norway, and the Rockall Trough and Porcupine Seabight off Ireland. In the northwest, it is found from southern Greenland and Baffin Island to Virginia, being particularly abundant in the Laurentian Channel, and may occur further south to the
Rockall flora and fauna. They chartered the "Granuaile". A detailed underwater mapping of the area around Rockall undertaken in 2011–2012 by Marine Scotland showed that Rockall itself is a minor pinnacle, whilst Helen's Reef extends in a sweeping arc of fissures and ridges to the north-west of the islet. Between the islet and Helen's Reef is a deeper trench much used by squid fishermen. The area where Rockall is in, is located in the pathway of the warming and moderating Gulf Stream. Although the rock does not sustain any weather station, the isolated nature of the setting dictates an extremely maritime