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Toothy Sawfish Doomed by Own Design

Jennifer Viegas, Discovery News

The fish's electro-sensitive rostrum acts like a metal detector, allowing sawfish to search, and dig into, the sea floor. The saw is also used to fend off would-be attackers.

Although Florida newspaper accounts of sawfish catches suggest the fish was plentiful there around the turn of the 20th century, the fish are now forced to hide out at more remote spots. The sawfish also have a nursery area for their young in South Florida waters.

Another remaining sawfish refuge is in Brazil at the mouth of the Amazon River, which Burgess just visited.

As for the Florida Everglades, human access to the site is limited, so it's one of the few places in the world where the fish can thrive. Under other circumstances, sawfish frequently ascend from the sea floor into bays and estuaries, where fatal encounters with fishermen frequently occur.

Compounding the problem is that, like many sharks, sawfish grow slowly, reach sexual maturity at around 10 to 12 years of age, and have a low reproductive potential. Although individuals may have a life span of 30 years or more, they give birth to live young, a process that requires a prolonged gestation period.

Other researchers are very concerned about the fate of sawfish and their shark and ray relatives.

This year, an international study organized by the International Union for Conservation of Nature and Natural Resources (IUCN) Shark Specialist Group, determined that over 50 percent of such species are now threatened with extinction.

"The traditional view of oceanic sharks and rays as fast and powerful often leads to a misperception that they are resilient to fishing pressure," said Sonja Fordham, who worked on the IUCN project.

Both she and Burgess hope better data, improved monitoring and catch limits can help to turn the extinction tide.

"In the case of sawfish, we're talking about a recovery process that requires 100 years," Burgess said.

He added, "I won't live to see it, nor will my children, but hopefully their children will."

Related Links:

National Sawfish Encounter Database

Mote Marine Laboratory Sawfish Conservation Research

How Stuff Works: Skates and Rays