As their name suggests, spiny dogfish sharks sport sharp, venomous (poisonous) spines in front of each dorsal fin. Their bodies are dark gray above and white below, often with white spotting on the sides.
Despite their small size, spiny dogfish are aggressive and have a reputation of relentlessly pursuing their prey. The name "dogfish" stems from their habit of feeding in packs—sometimes numbering in the hundreds or thousands. Gathered together, they sweep an area, eating the fishes in front of them. They'll eat almost anything they can get their strong jaws and teeth on. Newborn dogfish will even attack fishes two to three times their size.
Spiny dogfish are not in demand as a food item in the United States, but they're popular on the international market. If you order "fish and chips" in Europe, for example, you'll probably be eating spiny dogfish shark meat. The size of north Atlantic fishing catches that supply this market climbed sharply between 1988 and 1998, leading researchers to declare the dogfish shark overfished. Spiny dogfish don't become sexually mature until 20 years old, so overfishing can be devastating to populations. To protect dogfish populations, quota limits were established in 2000 in waters from Maine to Florida; once the quota is filled, dogfish shark fisheries are closed for the season.
You can read more about the sustainability of sharks as a food item in the Seafood Watch section of our web site.
All sharks have unique skin. It's covered with toothlike scales called denticles—unique to sharks and very similar to the teeth of all vertebrates—which make the skin rough and abrasive. In fact, shark skin was once dried and then used as sandpaper to polish wood. Today, shark skin is still cured and, after the denticles are removed, used as leather.
This shark probably has the longest gestation (pregnancy) period of any vertebrate—22 to 24 months.
Spiny dogfish sharks are long-distance travelers. One spiny dogfish tagged and released from Washington State showed up off the coast of Japan—a 5,000-mile journey.