Spiny dogfish - Squalus acanthias
WHAT TO LOOK FOR
A small slender slow-swimming shark with a narrow, pointed head, a single short spine anterior to each dorsal fin, and lacking an anal fin.
The shark is grey to bluish grey or greyish-brown above, lighter or white below, and often with white spots on its flanks, and dusky tips of its dorsal fins.
Males reach maturity at 1.9 to 2.4 feet [59 to 72 cm], females at 2.5 to 3.2 feet [76 to 100 cm].
Found from the surface to depths of 3,000 feet or more. Appears to prefer temperatures from 44° to 59°F [7° to 15°C].
Almost worldwide, except tropics and near poles. Very little mixing of northern and southern hemisphere populations.
General – A very long-living, slow-growing, late-maturing species. Age at maturity varies regionally. Males mature around 10 to 25 years, females at 18 to 23 years. May live 75 to 100 years.
Reproduction – Aplacental viviparous, with an 18 to 24 month gestation period before giving birth. Litters average up to 20 pups.
This species may form large aggregations on feeding grounds.
Some stocks seriously depleted or collapsed. International Union for Conservation of Nature (IUCN) Red List: Near threatened globally / Endangered in the Northeast Atlantic.