The spined pygmy shark is one of the smallest sharks; it is roughly 7 to 8 inches (18 to 21 cm) long (females are about 8 inches = 21 cm long; males average about 7 inches = 18 cm long). This deep water shark has a spine in front of its first dorsal fin but not in front of the second dorsal fin (this is unique among sharks). It also has a luminescent (glow-in-the-dark) belly.
Deep-water shark - Portuguese dogfish or Siki
Centroscymnus coelolepis
Deep-water sharks are landed both in targeted fisheries and as by-catch in French trawl fisheries for blue ling and roundnose grenadier. Data shows landings of deep-water sharks have increased markedly since 1990 reaching nearly 5000 tonnes in 1996. 2 species of deep-water shark are routinely landed - Portuguese dogfish and the Leafscale gulper shark.