The spiny dogfish shark is the most abundant shark. This small shark is also known as the piked dogfish, skittledog, spotted dogfish, white-spotted dogfish, codshark, and thorndog. Its dorsal fin has spines that are mildly poisonous. More is known about it than any other species of shark; it is often studied in scientific laboratories. It is used extensively by people as food, fertilizer, hide, pet food, and liver oil.
