Caught incidentally in the commercial fishery off the outer Washington coast with longline, troll, and jig handline gear. This species of shark is a very fast, strong swimmer and has been known to leap entirely out of the water! This shark can also maintain a body temperature warmer than the water surrounding it, a trait it shares with its relatives: makos and great whites.
Description and Range
Physical description
The common thresher is a fairly slender, torpedo-shaped shark and is named for its exceptionally long, thresher-like tail (which can be as long as the total body length). The dorsal surface of this species is dark green to bluish or purplish gray with lighter shades ventrally. The head is short with a cone shaped snout and a small mouth. The small mouth is arched and, unlike in other thresher sharks, has furrows at the corners. There are 32-53 upper and 25-50 lower tooth rows with teeth that are small, triangular, and smooth-edged, lacking lateral cusplets. This species has small dorsal fins and large, recurved pectoral fins. The five pairs of gill slits are short, with the fourth and fifth pairs located over the pectoral fin bases. This thresher species can be distinguished from the pelagic thresher by the white of its belly extending in a band over the bases of its pectoral fins. The common thresher is the largest of the three species of thresher sharks. This shark is an active predator and uses its tail as a tool to stun prey.
Common thresher sharks can grow up to 6.1 m (20 ft) in length, and 500 kg (1,100 lbs) in weight. Maximum age is 50 years old.
Geographic range
Common thresher sharks are found along the continental shelves of North America and Asia of the North Pacific, but are rare in the Central and Western Pacific. This species tends to be more common in coastal waters over the continental shelves. Although occasionally sighted in shallow, inshore waters, thresher sharks prefer the open ocean, and have been found in waters up to 550 m (1,800 ft). The common thresher is migratory, moving to higher latitudes following warm water masses. In the eastern Pacific, males travel further than females, reaching as far as Vancouver Island in the late summer and early fall.
Regulations
Rules and seasons
Recreational fishing for common thresher sharks is closed in all Washington waters. All three thresher shark species have been listed as vulnerable to extinction by the World Conservation Union (IUCN).