Endangered sawfish focus of national collection and recovery efforts

December 1st, 2008

The University of Florida, keeper of the world's shark attack records, is also now overseeing a national records collection for another toothy marine predator: the sawfish.

Distinguished by a long rostrum or "saw" that makes it a popular curio item and gives it its name, the sawfish has become a historical and cultural icon that is rapidly disappearing, said George Burgess, a UF ichthyologist and curator of both the International Shark Attack File and the newly expanded National Sawfish Encounter Database.

"Postcards from the turn of the 20th century often depicted this so-called monster that inhabited Florida waters, and if one goes back and looks at newspaper accounts from places outside Florida, every time a sawfish was caught it made the papers," he said. "Today, it's difficult to find a bar in South Florida that doesn't have a sawfish 'saw' hanging on the wall."

An important part of Florida's fauna, the sawfish once swam in bays, lagoons and rivers extending from New York to the Rio Grande, Burgess said. Today, its American range has shrunk to Florida and its declining numbers have made it the first species of marine fish to be placed on the list of federally endangered species, he said.

Burgess and a team of scientists at the Florida Museum of History on the UF campus plan to use information from the sawfish database to further enhance a management plan developed to help speed the species' recovery.

The National Sawfish Encounter Database is a compendium of all known historical and current records of sawfish in the United States, Burgess said. Databases formerly housed with the Mote Marine Laboratory in Sarasota, the Florida Fish and Wildlife Conservation Commission and two private sawfish enthusiasts are being combined with existing Florida Museum of Natural History records, he said.

Data from the collections will reveal the known distribution of sawfish throughout the United States, he said. Burgess plans to add to it new research results as he and his team monitor the abundance of sawfish and use tags to track their movements within the Indian River Lagoon and Banana River along Florida's east coast.

This area is critical to the recovery of the once widespread species, Burgess said. Historically, the region was full of sawfish, but the numbers drastically declined as development encroached on the creature's coastal habitat and its encounters with humans rose, he said.

"Sawfish are disappearing all over the world for basically the same reason, which is that their big saws snag very easily in fishing nets," he said. "They have become despised as net wreckers because obviously a fisherman doesn't like getting one in his net. So over the years most sawfish that were captured were killed."

Even those sawfish lucky enough to be tossed back into the water were often released without their saws, as people came to value these body parts as curio items, Burgess said.

Although the sawfish's body resembles a shark, the sawfish belongs to a class of fish called rays. Its elongated blade-like snout is used to stun and kill prey.

"Sawfish get lots of ooh's and aah's because humans tend to gravitate to the more charismatic megafauna, as it is characterized," he said. "We place more values on whales than their kin the field mice or the brown-eyed seal more than we do some wood rat."

Part of the sawfish's appeal may also be its increasing rarity, said Burgess, who estimates there are only a few thousand sawfish left in Florida.

It takes longer for the sawfish population to recover than other species because of its unusually slow growth, late onset of sexual maturity and low reproductive potential, Burgess said. Although the sawfish has a long life span of 30 years or more, it is a live-bearer. As such, it has a prolonged gestation period and produces very few young, he said.

Source: University of Florida