PORT OF THE ISLANDS — For thousands of years, the sawfish was one of the most ferocious predators roaming the marshy shorelines of the Florida Peninsula.
Fossil records found throughout the state show that the peculiar creature, which is closely related to both sharks and stingrays, and its evolutionary ancestors date back over 10,000 years.
It took less than 100 years for man to nearly wipe them from existence in North America.
“As a group, sawfishes are endangered not only here but on a global level,” University of Florida Program for Shark Research director George Burgess said. “Sawfish are a very visible indicator of human intervention into their habitat.
“We are directly responsible for their fate, both for having made it happen and for undoing the damage that has been done. It’s our obligation as good Floridians to see this through.”
Thanks to conservation efforts over the last two decades, the critically endangered species has started to rebound. Southwest Florida has been the epicenter of that resurgence. Encounters such as the video taken by Alex Pinto of a 14-footer caught and released off the Naples Pier that quickly went viral in April, or the approximately 10-foot fish caught off Sanibel Island in May anecdotally suggest that the species’ population is making a rebound, but there is still a long way to go to ensure the sawfish’s future survival.
“I probably won’t see (a full rebound) in my lifetime, but hopefully our kids’ grandkids will,” said Burgess, who also serves as the curator for the International Sawfish Encounter Database.
A PEST AND A PRIZE
That unique rostrum, the elongated snout lined with sharp toothlike denticles, was a major reason for the sawfish’s near-demise.
Since commercial fishing became a major industry in South Florida around the early 1900s, sawfish have been the bane of trawl and gill netters. Because of their rostrum and their tendency to comb the ocean floor, they frequently became entangled in those nets. Their raw size and power — they routinely reach 20 feet in length and up to 700 pounds — meant they could easily slash their way through hundreds of yards of netting, costing many small-time fishermen their livelihood.
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Mullet fishermen considered sawfish a pest and slaughtered them with impunity.
“That toothy snout tends would get caught up in those nets so it virtually doomed them to death,” Burgess said.
As sport fishing became a popular tourist attraction in Florida, the sawfish also became a frequent target for anglers who then removed the rostrum and kept it as a trophy. After several decades, it took a considerable toll on the population of the species.
Habitat loss has also been a major factor in the sawfish’s depletion. Since the mid-1800s, when man first began to settle the lower portion of the state, over 50 percent of the Everglades has been developed as agricultural or urban areas. This is especially true for coastal regions, which are the primary habitat for sawfish and vital to their life cycles, on both sides of the state.
Sawfish rely on the many rivers and sloughs that feed into mangrove estuaries to provide a spawning ground and a place for their recently birthed pups to take shelter until they are big enough to escape predation by larger fish such as sharks and even reptiles such as alligators and crocodiles that also call this part of Florida home.
By 1990, the largetooth variety of sawfish, which were primarily found in the western Gulf of Mexico, had completely disappeared, while the smalltooth sawfish was on the brink of extinction. Sightings became incredibly rare. Despite a historical range that once stretched northward all the way to New Jersey, there were just two confirmed sightings to the north of the state of Florida in the past 30 years.
According to Burgess, less than 10,000 fish were left in North America, mostly confined to Southwest Florida and the Florida Keys.
FIGHTING FOR SURVIVAL
In 1992, the state of Florida made the harvest or killing of any species of sawfish illegal. In 2003, sawfish became protected under the Federal Endangered Species Act. In 2007, Convention on International Trade in Endangered Species of Wild Fauna and Flora banned all sales of sawfish and any derivative products.
In 2009, NOAA Fisheries Service designated 619,013 acres of coastal habitat in the Ten Thousand Islands and the Florida Everglades as critical habitat for the species.
“We have a lot of estuaries where the fresh and saltwater mix,” Rookery Bay Research Estuary biologist Patrick O’Donnell said. “They are very productive systems, creating a lot of food and shallow habitat for all kinds of fish and other invertebrates.
“The young sawfish are born into that estuary and given a chance to grow and have lots to eat while not being preyed upon.”
O’Donnell has been studying adolescent sharks — including sawfish — in the Ten Thousand Islands watershed for the last 16 years.
“The juvenile habitat is perfect in Southwest Florida,” O’Donnell said of the species pupping season, which typically runs from January through late March. “The waters are warm with lots of structure and food. The lower fishing pressure in the backwater areas allows them to escape capture so they hopefully make it to adulthood.”
Although the sample size remains too small to draw any definitive conclusions, O’Donnell’s data seems to support the notion that there are more sawfish reaching sexual maturity — usually occurring between 10 and 12 years — and using Southwest Florida as a spawning ground.
Between 2000 and 2010, O’Donnell captured and tagged 26 sawfish during his study — most of which were between one and three years old. Six of those were fish that had already been tagged in previous studies. From 2011 to 2016, that same study encountered 33 sawfish with just two of them already affixed with a tag.
“I wouldn’t call (the combined conservation efforts) a total success yet, but it does show that the population is becoming more stable,” O’Donnell said.
Gregg Poulakis of the Florida Marine Research Institute’s Port Charlotte Field Lab has seen similar results in his research in the Charlotte Harbor watershed, including the Caloosahatchee and Peace rivers.
Poulakis has been studying the local sawfish since 2005. Part of his research involves implanting acoustic tags that can be detected by underwater receivers to track the fish’s movements in his study area. This information has revealed just how important Southwest Florida is in the pupping process of the fish.
“We found that adult females were tied to the area and would return to Charlotte Harbor every other year (presumably to give birth),” Poulakis said.
There is still much to learn, according to Poulakis.
“No one ever studied sawfish before them being put on the endangered species list,” he said, “even basic questions in terms of biology, ecology and habitat. Now we are slowly chipping away at those questions.”
Recreational anglers and commercial fishermen, the same groups who once helped force the sawfish to the brink of extinction, have become instrumental in answering some of those questions. Sighting databases administered by the FWC and the UF’s ISED have allowed researchers to partner with those who are most likely to encounter a sawfish to create a network of observers throughout the state to record size, location and habits of these fish.
“Info gathering has never been easier,” Burgess said. “With all the technology and social media, citizens act as scientists when it comes to collecting valuable data about them.”
“It has been absolutely critical,” Poulakis said. “Each of those calls and emails adds up. It helps us direct our research and we use the information a lot in our studies.”
According to Burgess, who has been conducting research expeditions with his team in the Florida Keys this summer to tag adults with long-range tracking devices, the next step in the species’ recovery will come from the ability to expand beyond the confines of South Florida and re-establish populations farther north.
That next step in their recovery could be in jeopardy, however, unless there is a concerted effort by all Floridians to understand and protect the fragile species.
“The decline took a century and it’ll take at least another century to get them back,” Burgess said. “That recovery is slowed by every animal that is killed at the hands of a human. That’s on all of us.”
Source: archive.naplesnews.com