It's true, these unique animals are in decline because of their unique design. But the fault still partially lies on humans, because if humans were not setting out nets, these fish would not be declining so rapidly.
http://dsc.discovery.com/news/2008/12/02/sawfish-shark-02.html
Toothy Sawfish Doomed by Own Design
Jennifer Viegas, Discovery News
Dec. 2, 2008 -- New efforts are underway to save the sawfish, an iconic, shark-like fish that has experienced steep population declines in recent years, primarily because its distinctive saw-shaped snout easily tangles in nets, angering fishermen.
In 2003 the sawfish became the first marine fish to be placed on the list of federally endangered species. It's been on the list ever since.
"Commercial fishermen have never liked sawfish," George Burgess, a University of Florida ichthyologist, told Discovery News. "They routinely kill sawfish because they can cause costly damage to nets."
Burgess is a University of Florida ichthyologist who serves as curator of both the International Shark Attack File and the National Sawfish Encounter Database. He's calling on the public to help with a new expansion of the sawfish database that is bringing together files formerly housed with the Mote Marine Laboratory, the Florida Fish and Wildlife Conservation Commission and two private collections.
"We'd like for anyone who has seen a sawfish in the wild to report the sighting using the form at the Florida Museum of Natural History web site," he said, explaining that the information will be used to better reveal the distribution of sawfish.
Sawfish, which can grow to anywhere from 4.6 to 23 feet in length depending on the species, once had a range that extended from the waters off of New York to the Tex-Mex border. Now it's thought that sawfish "are essentially confined to Florida," according to Burgess.
South Florida was always a primary destination for the flat-headed fish.
"I think every bar there has a sawfish saw hanging on the wall," he said, adding that while the fish can survive without the saw, its ability to hunt is severely compromised.
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."
1 comment:
Ironically, while the sawfish is critically endangered and nearing extinction, the populations of almost every other ray species have actually been booming, due to the overfishing of bony fish and the removal of the ray's main predators, sharks.
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