The spiny dogﬁsh is the most prominent member of the Squalidae family of dogﬁsh sharks. Some live in relatively shallow water close to shore; others inhabit great depths. They vary widely in length, and one of their chief anatomical characteristics is the lack of an anal ﬁn.
IdentificationThe body of the spiny dogﬁsh is elongate and slender. The head is pointed. The color is slate gray to brownish on top, sometimes with white spots, and fading to white below. It has spines at the beginning of both dorsal ﬁns; these spines are mildly poisonous and provide a defense for the spiny dogﬁsh.
Size/AgeSpiny dogﬁsh are common at 2 to 3 feet in length; the maximum size is about 63 inches and 20 pounds. In California waters, a large fat female will be roughly 4 feet long and will weigh 15 pounds. In the north-western Atlantic, maximum ages reported for males and females are 35 and 40 years, respectively.
Life historySpiny dogﬁsh tend to school by size and, for large mature individuals, by sex. Females are larger than males and produce from 3 to 14 young at a time in alternate years. The species bears live young and has a gestation period of about 18 to 22 months. Spiny dogﬁsh are long lived and nonmigratory; heavy commercial ﬁshing pressure in a given area will rapidly lower populations of this slow-growing, low-reproductive species.
Food and feeding habitsThe spiny dogﬁsh is voracious and feeds on practically all smaller ﬁsh, including herring, sardines, anchovies, smelt, and even small spiny dogﬁsh and crabs. They have been known to attack schools of herring and mackerel, as well as concentrations of haddock, cod, sand lance, and other species.
Other Namesdogﬁsh, dog shark, grayﬁsh, Pacific grayﬁsh, Pacific dogfish, spinarola, California dogﬁsh, blue dog, common spiny ﬁsh, spiny dogﬁsh, picked fish, spiky dog, spotted spiny, spurdog, white-spotted dogﬁsh, Victorian spotted dogﬁsh; French: aiguillat; Italian: spinarolo; Japanese: aburatsunozame; Portuguese: galhudo; Russian: katran; Spanish: galludo.
|Spiny Dogfish (Squalus acanthias)|