Thursday, January 24, 2008

Saw Shark


The sawsharks or saw sharks are an order (Pristiophoriformes) of sharks bearing long blade-like snouts edged with teeth, which they use to slash and disable their prey. There are five described (and four undescribed) species known, in a single family Pristiophoridae of two genera. Most occur in waters from South Africa to Australia and Japan, at depths of 40 m and below; in 1960 the Bahamas sawshark was discovered in the deeper waters (640 m to 915 m) of the northwestern Caribbean.

Sawsharks also have a pair of long barbels about halfway along the snout. They have two dorsal fins, but lack anal fins, and range up to 170 cm in length. Genus Pliotrema has six gill slits, and Pristiophorus the more usual five. The teeth of the saw typically alternate between large and small.
The sharks typically feed on bony fish, shrimp, squids, and crustaceans, depending on species. They cruise the bottom, using the barbels and ampullae of Lorenzini on the saw to detect prey in mud or sand, then hit victims with side-to-side swipes of the saw, crippling them.
Most of the species are fished commercially, and their meat is considered to be of excellent quality. Japanese sawshark is used to make kamaboko, a traditional type of fishcake.
Although they are similar in appearance, sawsharks are distinct from sawfish. Sawfish have a much larger maximum size, lack barbels, have evenly sized rather than alternating sawteeth, and have gill slits on their undersurface rather than on the side of the head.

2 comments:

Unknown said...

@one was reacently caught in the red sea saudi arabia yanbu

Unknown said...

This appears to be a sawfish (Order: Pristiformes) rather than a saw shark (Order: Pristiophoriformes)

Seom key distinguishing features include the gill location (sides for the saw shark, bottom for the sawfish), size (sawfish is typically larger), and features of the saw "tines" themselves.

In particular, the pictured fish lacks the "pair of long barbels about halfway along the snout" that a saw shark should have. See http://upload.wikimedia.org/wikipedia/commons/3/3d/Pristiophorus_nudipinnis.jpg and http://en.wikipedia.org/wiki/File:Sawfish-plate.jpg to compare