Similar in appearance, the two makos were not recognized as separate species until 1966. The primary difference is the length of their pectoral fins. Shortfin makos have shorter fins, about half to three-quarters the length of the head, while longfin makos have fins about equal to head length. Shortfin makos also display snow-white coloring around the mouth and snout. Sand tiger sharks are popular for aquarium displays because they adapt better to captivity than most species.
Dogfishes are probably the most important commercial species in the Northeast.
Spiny dogfish in particular gained prominence in the fishery with the depletion of cod, haddock and other groundfish stocks. Spiny dogfish meat is marketed in England for use in fish and chips. Similar in size at 4 to 5 feet, they differ mainly in fin structure, with the spiny dogfish having dorsal fins each preceded by a single spine. The smooth dogfish has no spines, but has dorsal fins of nearly equal size. Final Fishery Management Plan for Atlantic Tuna, Swordfish, and Sharks.