squalus

Squalus is a genus of sharks in the family Squalidae, commonly known as spiny dogfish or dogfish sharks. It is the type genus of its family, and the best-known species is the spiny dogfish, Squalus acanthias, which has a widespread distribution in temperate waters.

Members of Squalus are small to medium-sized sharks with elongated bodies, two dorsal fins each bearing a spine, no anal fin, and relatively large pectoral fins. They typically have a pointed snout and a brown to gray dorsal coloration with a lighter underside. Their teeth are adapted for grasping slippery prey such as small fish and invertebrates.

Distribution and habitat: Squalus species occur worldwide in temperate and subtropical seas, mainly along continental shelves and upper slopes. They inhabit coastal waters to relatively deep offshore habitats, depending on the species, from nearshore zones to several hundred meters depth.

Reproduction and life history: Most Squalus species are ovoviviparous, with embryos developing inside eggs retained within the mother until hatching. Litter sizes vary by species, often ranging from only a few to several dozen pups. Growth and maturity are relatively slow compared with many bony fishes.

Fisheries and conservation: Spiny dogfish are of commercial importance in many regions, particularly S. acanthias and related species. Fishing pressure has led to declines in some stocks, and regional management measures are in place to regulate catch, monitor populations, and promote sustainable yields.