Author: (Linnaeus, 1758)
Field Marks:
A slender, dark-spotted catshark with greatly expanded anterior nasal flaps, reaching mouth and covering shallow nasoral grooves, labial furrows on lower jaw only, second dorsal fin much smaller than first.
Diagnostic Features:
Head and body relatively deep, slender and narrow; greatest width of head less than 2/3 of head length. Shallow nasoral grooves present between excurrent apertures of nostrils and mouth; anterior nasal flaps broadly expanded medially and posteriorly, nearly meeting each other medially and extending to the mouth. First dorsal origin well behind pelvic insertions; second dorsal origin over anal insertion. Interdorsal space slightly greater than anal base. Denticles small, skin not extremely rough. Colour pattern of numerous small dark spots, usually about size of eye pupil; 8 or 9 dusky saddle marks sometimes present but often obscure or obsolete; scattered white spots sometimes present. Size moderate, to 100 cm.
Geographical Distribution:
Eastern North Atlantic: Norway and British Isles to Mediterranean, Senegal, ? Ivory Coast.
Habitat and Biology:
An abundant temperate bottom-dwelling catshark of the European continental shelves and uppermost slopes, on sandy, coralline algal, gravel or mud bottoms at depths from a few metres commonly down to 110 m and exceptionally to 400 m; sometimes occurs in midwater. Young sharks and hatchlings are found in shoaler water than adults, which often occur in unisexual schools. On the spawning grounds adult females show up first in early winter and preponderate in numbers until early spring, when adult males join them. In late summer adults of both sexes move into deep water where mating occurs.
Oviparous, laying eggs one per oviduct at a time. Spawning occurs in shallow water, often in sandy areas; egg-cases are often deposited on algal substrates, mostly subtidally but sometimes in the lower intertidal, and hatch in 5 to 11 months (most in 8 to 9 months). Eggs may be laid all year in shallow water but most are deposited from November to July, with local populations apparently showing differences in deposition time. A single egg is laid per oviduct at a time. Eggs vary in size according to locality and size of female. In Mediteranean waters, with smaller females than the eastern Atlantic, egg-cases are about 4 cm long by 2 cm wide, while sharks off the United Kingdom lay eggs 5 to 7 by 2 to 3 cm.
Feeds mostly on molluscs and crustaceans, especially whelks but also other gastropods; scallops, razor clams and other bivalves; small cephalopods; and hermit and swimming crabs, lobsters, slipper lobsters, and shrimp. Also eats polychaete worms. This shark takes a variety of small, mostly bottom-dwelling bony fishes such as gurnards, flatfish, and gobies, but also takes herring and pilchard, small gadoids like whiting and pouting, jacks and mackeral.
Size:
Maximum recorded about 100 cm (British Isles and North Sea), maximum and size at maturity less in Mediterranean than elsewhere; Mediterranean males mature at 39 cm and reach 60 cm, females mature at 44 cm and reach at least 60 cm; size at hatching 9 to 10 cm.
Interest to Fisheries:
This is a moderately important commercial species in European waters, particularly around the British Isles. It is primarily taken by bottom trawls, but also fixed bottom nets and even pelagic trawls. It is utilized fresh and dried-salted for human consumption, also for oil and fishmeal.
Remarks:
Several writers have pointed out that eastern Atlantic members of this species are considerably larger than Mediterranean sharks. Garman (1913) even went so far as to name a new species, Catulus duhameli, for Mediterranean canicula. This is generally not recognized by more recent writers, but still some populational differentiation of this shark apparently exists, which may eventually be expressed as subspecies.
Type material:
Holotype: Apparently none. Type Locality: "Habitat in Oceano Europae".