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by twenty5degrees January 16, 2020 9 min read

Normally, a one-fish day is nothing noteworthy, but when that one fish looks like nothing you’ve ever seen before in your life—as much for its over-the-top odd looks, as for its scarcity—that day creates an indelible memory. Simply put, Dr. Gregg Poulakis hopes his team’s work will lessen the latter.

Right off the bat, let’s clarify a critical point: This was no sportfishing mission; rather one designed to help ensure the survival and, ideally, the expansion of Florida’s most unique marine species—the smalltooth sawfish. In his role as a fisheries biologist for the Florida Fish and Wildlife Conservation Commission’s Fish and Wildlife Research Institute (FWRI), Poulakis has been keeping tabs on the state’s sawfish population since 2004—a welcomed task motivated by regrettable causes.

Once fairly abundant throughout the Gulf of Mexico’s estuarine and coastal waters from Texas to Florida, as well as the Atlantic Coast into North Carolina, sawfish numbers have dramatically decreased over the past century. Today, the impacts of commercial net bycatch mortality and habitat loss have diminished the sawfish population to South and Southwest Florida.

“They were considered a nuisance to net fishermen,” says Poulakis. “Imagine a fish that could become entangled more easily than one with a saw for a nose.”

Starkly contrasting the higher reproductive rates of broadcast spawning fish, sawfish biology has made its road to recovery a long one. It takes about seven years for females to reach sexual maturity, after which they’ll give birth to broods of seven to 14 young every other year, following a 12-month gestation period.

Recognizing the species’ dire situation, Florida protected sawfish from harvest in 1992. Eleven years later, the smalltooth sawfish became the first shark or ray species to receive federal protection under the Endangered Species Act. This designation makes it illegal to catch, harm, harass, or kill a sawfish.

In addition to U.S. protection, the International Union for Conservation of Nature (IUCN) lists all sawfish species as “Endangered” or “Critically Endangered” on its Red List. Furthermore, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) prohibits any commercial trade in sawfish.

So, What Is a Sawfish?

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Joining sharks and rays in the elasmobranch clan, sawfish are built over a cartilaginous frame that works in concert with a low profile and flat belly to allow efficient movement through whisper-thin depths. With its primary and secondary dorsal fins roughly the same height as the upper caudal (tail) fin, a sawfish breaking the surface is easily identified by what looks like a trio of triangles.

The saw’s signature feature—the rostrum—sports a collection of sharp tooth-like spikes known as rostral teeth, which are actually modified scales similar to the raspy protrusions of a shark’s skin. Swinging its snout in lateral sweeps, the sawfish uses the rostrum to stun forage fish for easier meals and to convince would-be predators that it’s not to be trifled with.

Notable design elements include eyes that set high and forward for a streamlined profile that allows a saw to see while laying in a muddy bottom. Also, an up-close look reveals intake vents (spiracles) behind the eyes for circulating water through the gills and out on the saw’s underside for exhaling. As crew member John Hadden notes, this allows the fish to breath while laying on the bottom without drawing in mud.

“Sawfish are born with a flexible rostrum and a sheath covering the rostral teeth,” says FWRI Fisheries Biologist Rachel Scharer. “The sheath dissolves shortly after birth so the baby sawfish can begin feeding.”

Clues From Scientific Sampling

While other efforts, like those of Dr. Dean Grubbs from Florida State University’s Coastal and Marine Laboratory, target adult sawfish from South Florida to the Bahamas, Poulakis’s team focuses on juvenile sawfish up to 10 feet long (adults can reach about 16 feet). While adult sawfish are found in coastal and offshore waters along southwest Florida and the Florida Keys, the primary nursery habitats for juveniles are found within estuaries such as Charlotte Harbor (Peace and Myakka river mouths) and the Caloosahatchee River mouth’s union with San Carlos Bay at the lower end of Pine Island Sound.

Poulakis’s team used to conduct sawfish research trips year-round, but results have shown March through September as the most productive period. Small juvenile sawfish don’t leave the estuaries during fall and winter, but lower water temperatures tend to decrease activity levels and minimize capture success.

During the warm season, FWRI’s research team runs eight trips per month. Target areas may be “random”—computer-generated destinations—or “directed”—spots that have either yielded previous sawfish captures or come from public sighting reports via the Sawfish Hotline (1-844-4SAWFISH).

“For scientific sampling, randomness is necessary,” Poulakis says. “You don’t always want to go to the honey hole or try to assess the population based on your favorite fishing spot. There can be some value in that, but if you’re looking at a fairly large area that could be used, the scientific approach is to let the computer pick your spots so there’s no bias. Then, you can fairly assess the relative abundance—is the trend up or down—in a statistically valid way.

“As for the directed sampling, with an endangered species, if we did only random sampling, we might not tag that many fish,” he continues. “So for us to get tags out and answer other questions, we use the public reports from the hotline.”

Listening for Tagged Sawfish

During my observation trip, Scharer helmed the research vessel Limnatus—a 20-foot mullet skiff ideal for shallow water navigation—while Hadden took periodic depth readings with a marked PVC pipe to ensure the team remained in a safe navigational range of about 2 feet.

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Alia Court monitored an Ultrasonic Telemetry Tracking Receiver, called a hydrophone, which listens for signals from previously tagged sawfish. Court said she starts with a wide listening range in all directions and if she detects any pings transmitted from tagged sawfish, she’ll give Scharer the direction for a more focused effort.

With acoustic tags programmed to go off every 60 to 180 seconds, the team gives each area a 3-minute cycle. Seven pings confirms a tagged sawfish with its tag ID number displayed on the hydrophone and gives the team a dialed in location to try and recapture the fish for evaluation.

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Capture techniques include:

Drum Lines: Ideal for sampling in deeper holes where larger juveniles often lay, this tool employs a single baited line attached to the eyelet of a concrete base. Multiple drum lines may be used in a specific hole depending on its size. Cut ladyfish or mullet on circle hooks often tempts saws, which remain safely tethered until the team’s same-hour return.

Gill Nets: Utilizing the same type of capture device that decimated sawfish stocks might sound odd, but FWRI nets are monitored 100 percent of the time and entangled sawfish are promptly removed with the care of a veterinarian delivering kittens.

“They like shallow water, so we’ll set the net around a shallow pocket,” Hadden says. “When something gets caught in the net, you’ll see that top black line move. We’ll give it 30 minutes and if we don’t see any movement, we’ll walk over to the net with (capture) tubs to make sure that one isn’t just sitting there. That’s what SAW stands for: sit and wait.”

Gathering Data

When a sawfish bites a drum line or runs into the net, it’s placed in a water-filled tub or held in the water while the team readies the exam gear. With a gill net deployed, the team retrieves the mesh before commencing their work up.

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“We do that so another sawfish doesn’t get caught in the net while we’re working on the one we’ve captured,” Scharer says. “We may spend 30 minutes on a captured sawfish and we don’t want to risk another one struggling in the net and possibly injuring itself.”

Initial exams measure the fish’s rostrum and overall length, check for parasites, inspect rostral teeth to note any that are missing or damaged, and document any scars or injuries. (Sawfish are generally docile, but they don’t always play nice with others.)

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Complementing the DNA sample, each captured sawfish gets a Passive Integrated Transponder (PIT) tag injected at the base of its dorsal fin. About the size of a rice grain, a PIT’s unique identification number registers on the handheld scanner passed over each sawfish. (Similar to the microchips implanted in dogs and cats.)

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The last step is the acoustic tag that allows researchers to listen via hydrophones within the harbor and around the state. Saws under 3 feet get their acoustic tags glued to a base that is hole-punched onto a dorsal fin. Those longer than 3 feet receive a surgically implanted tag placed just under the belly skin with a small incision sutured shut before release.

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Dorsal-mounted acoustic tags last about a year before detaching, but the internal tags are built for at least a decade of use. Poulakis said his team is evaluating the size at which smaller sawfish can handle internal acoustic tags, as the goal is to someday implant every captured fish with a 10-year device.

“Being able to catch fish and put those 10-year acoustic tags in them, we’re going to learn a tremendous amount,” Poulakis says. “We’ve only been using those tags for about two years now and we’ve already started to make some connections with where fish are going.”

“The medium size fish are starting to leave Charlotte Harbor, going down to the Lower Florida Keys and a few have returned to the harbor. These are immature fish leaving and coming back, so in the next couple of years, we’ll start seeing patterns and we’ll relate those to other research we’ve done.”

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The 3 1/2-foot sawfish I observed gave Court and Hadden little more than the occasional squirm. This fish was so chill that it allowed team member Chris Hessell and me ample opportunity for thorough photography—even during Scharer’s skillful boat side surgery.

If you’re wondering how a team of fisheries biologists can safely manage a dangerous creature during a process that can last half an hour, the answer is very carefully. It’s typically a two-person job and the one on the business end uses leather welding gloves to maintain a safe, secure grip on that formidable snout. Keeping the fish in the water between each stage of the operation maintains respiration and minimizes stress for what Poulakis describes as a hardy species with a strong immune system.

“Some of the stress physiology work that’s been done shows that sawfish are tough fish,” he says. “They’re able to withstand that short amount of time in the net and getting them tagged,” he says. “We haven’t had any die during our research since we started.”

How Fishermen Can Help

Noting that he and his team catch about 50 to60 sawfish a year, Poulakis says they welcome input from anglers, waterfront homeowners and anyone who encounters a wild sawfish. Clear, calm days may reveal a shallow sawfish to someone standing on a dock, drifting in a kayak or fishing in a flats or bay boat. Targeting sawfish is illegal, but they occasionally turn up on lines cast for neighboring species.

Whatever the encounter, Poulakis urges citizens to call the hotline (again, 1-844-4SAWFISH) and report location, estimated length that includes the saw (using a boat or shoreline point for reference), date, and bait and tackle details for a sawfish catch. And don’t blow off the chance to contribute, Poulakis said. There’s no such thing as inconsequential data.

“We’ve heard anglers say ‘I’ve only caught one, does it really matter?’ but all those ones add up,” Poulakis says. “We want to use this info to help our research and get some tags out, but we’re respectful of people’s fishing holes. We’re not going to camp out there for weeks on end.

“The hotline info is also used for other things like the juvenile sawfish critical habitat designation, which came from hotline data. Plotting all of those reported captures, we were able to designate some areas that clearly were important for young sawfish. We haven’t been able to do that with the larger juveniles and adults, but that is something we’re hoping to be able to do with some of the acoustic data.”

It’s important to note that anglers who catch sawfish are advised to keep them in the water and cut the line/leader as close to the hook as possible. Hooks will dissolve in saltwater, but trailing leaders risk entangling the rostrum and impeding the fish’s feeding. Also, no gaffs, no ropes, and no handling—even a small sawfish can send you to the ER, so don’t risk your safety or the fish’s.

Are you wondering: What’s the objective here? How does all this netting and snipping and tagging and hotlining impact the smalltooth sawfish?

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“These fish are endangered and they need our help,” Poulakis says. “All the research we’re doing is to try and answer questions about the biology and ecology of these animals that no one could answer before. These things were never studied before they were protected, so even basic questions about their biology or ecology—How big do they get? What do they eat? How old do they get?—no one had answers to those questions.

“Over the years, we’ve been chipping away at some of those questions and we still have some to answer,” Poulakis continued. “The idea is to learn as much as we can about the species and how it relates to its environment so we can maximize recovery. The ultimate goal is to get these animals to a healthy enough population level where we can maybe down list them from endangered, which is the most at-risk of extinction designation, to threatened and then eventually off the list.”

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If all goes well, maybe more folks will have the opportunity to see Florida’s favorite oddball in its natural setting. Just remember: Look, don’t touch.

For information on Florida fisheries visit myfwc.com

Images were taken under the authority of NMFS ESA Permit No. 21043.

Written by David A. Brown for Field & Stream and legally licensed through the Matcha publisher network. Please direct all licensing questions to legal@getmatcha.com.


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