A joint effort is underway to tag, study and track threatened sawfish.

Three recent projects of the Florida Program for Shark Research at UF’s Florida Museum of Natural History focused on the distribution and movements of adult sawfishes in the southern portion of Florida. Also known as the “carpenter shark,” sawfish are a family of rays, characterized by a long, toothy nose.

The family as a whole is largely unknown, but Florida Program for Shark Research Director and shark expert George Burgess explained some of the ongoing sawfish studies he and his crew are conducting in the waters around South Florida. One study is in partnership with researchers from Florida State University.

Sawfish

“We produced a survey of the waters surrounding U.S. Navy properties in the Key West region in order to determine the current status of sawfishes in those areas for the U.S. Navy/U.S. Army Corps of Engineers,” explained George Burgess. Because of obvious security constraints, they were the first fish biologists to sample in these waters in decades.

In conjunction with Dean Grubbs and fellow FSU scientists, and John Carlson of the National Marine Fisheries Service, Burgess sampled the Middle and Lower Keys, Tortugas region, and Florida Bay, catching and satellite-tagging 11 sawfish. Several species of sawfish can grow to approximately 23 feet.

“Satellite tags give long time and distance of movement information and we hope our tagging will help us better understand seasonal horizontal (up and down the coast) and vertical (depth) movements of the critters. We also caught and multiple tagged two large adults in Florida Bay, the tags being traditional spaghetti, satellite, and active acoustic models.”

Acoustic models allow researchers to manually track the minute-to-minute movements of sawfish, using a receiver held under the boat. Burgess’ research group’s first sawfish was “lost” within the first hour or so as it scooted over a shallow bank, then “boogied” before they could detect its signal.

“Having learned our lesson, on our second capture we got in 38 hours of tracking over three days, including day-night comparisons,” said Burgess. “The sawfish moved about in deeper channels by day, and then moved onto shallow, seagrass beds by night. It chose the same shallow grassy area on successive nights, demonstrating some short-term site fidelity.”

Next spring Burgess plans to initiate placement of underwater listening stations on the bottom and tag the sawfishes with passive acoustic tags. These tags will leave a unique “bleep” on any receiver as the sawfish swims near, allowing tracking of localized movements over longer periods and larger areas.

Sharks

While sampling for sawfishes George Burgess and fellow researchers caught many sharks and rays. All of these animals were measured, sexed, sampled (tissue for DNA) and tagged as part of ongoing studies of their biology and movement patterns.

“We also continued our work in Indian River Lagoon (IRL), where we began tagging young bull sharks with spaghetti and passive acoustic tags in a new region for us, the St. Lucie River Estuary,” said Burgess. The work is being done with colleague, David Snyder, of Continental Shelf Associates.

“Plus, we continue to download data from our underwater array of receivers in Mosquito Lagoon, Banana River and the northern IRL, where tagged bull sharks and rays still roam.”

Conservation Collaboration

In October 2010, the Guy Harvey Ocean Foundation and Hell’s Bay Boatworks donated a custom boat and trailer, valued at more than $50,000, to the Florida Program for Shark Research. During this time period, researchers put 5,000 miles in land travel on the Guy Harvey adorned Hell’s Bay and countless amounts of sea miles.

Below is a recent video about the Guy Harvey Ocean Foundation, Hells Bay Boatworks and Florida Program for Shark Research collaboration: