OUTDOORS

Sawfish mating grounds may have been found

Staff reports

Dan Grubbs (top), of Florida State University, helps to "roll over" a mature sawfish in order to insert an acoustic tag to allow for tracking of the endangered marine fish. Earlier this month, researchers discovered an area of the Everglades where sawfish gather in order to mate.

Science is catching up with one of the most mysterious marine fishes found in Florida's waters.

After 17 years of research on the smalltooth sawfish, scientists have discovered a mating ground for the endangered fish.

During an expedition in early April to the shallow-water backcountry of Everglades National Park, a research team captured, tagged and released three adult sawfish (one male and two females) in an area previously known almost exclusively as juvenile sawfish habitat. All three had distinctive lacerations, apparently sustained during mating, that match the pattern of teeth on the animals’ saw-like snouts.

The team includes scientists from Florida State University and the National Oceanic and Atmospheric Administration who conduct ongoing research permitted under the Endangered Species Act to monitor sawfish population health.

“We’ve long assumed sawfish mating was a rough and tumble business, but we had never before seen fresh injuries consistent with recent mating, or any evidence that it was happening in areas we’ve been studying primarily as sawfish pupping grounds,” said Dr. Dean Grubbs, associate director of research for FSU’s Coastal and Marine Laboratory. “Figuring out where and when sawfish mate, and whether they do so in pairs or aggregations, is central to understanding their life history and ecology.”

Scientists backed up their observations with ultrasound and hormone analyses that indicated the females were preparing for pregnancy. Florida researchers have caught adult male and female sawfish together on only a few occasions and in a few locations.

“We are all very excited by this monumental development in our efforts to uncover the mysterious mating habits of sawfish,” said Tonya Wiley, owner and president of Haven Worth Consulting, with 16 years of experience studying sawfish. “While much of Southwest Florida has been designated as ‘critical habitat’ for smalltooth sawfish, this discovery underscores the exceptional importance of Everglades National Park to the conservation and recovery of the species.”

Researchers in the Everglades work quickly to place a radio transmitter inside this sawfish, shown on its back in this photo, before releasing it. Recently, a team of sawfish scientists discovered what is believed to be a mating area for the unique and endangered species of fish.

The smalltooth sawfish (Pristis pectinata) was listed as ndangered under the Endanger Species Act in 2003. Under NOAA's leadership, the listing prompted strong federal protection for the species, safeguards for critical habitat, a comprehensive recovery plan and carefully controlled research.

“Florida’s sawfish have a long road to recovery, but exciting breakthroughs so far provide lessons and hope for other endangered populations around the world,” said Sonja Fordham, president of Shark Advocates International, a project of The Ocean Foundation. “The new findings can help efforts to protect sawfish at critical times, but also highlight the need to protect the park system that ensures suitable habitat, the funding for research and the overarching law that has made success to date possible.”

Adult sawfish are occasionally caught and released by anglers fishing the shallow waters of Florida's estuaries including the Indian River Lagoon, St. Lucie River and Caloosahatchee River, or offshore. Earlier this year, commercial diver John Dickinson of Jupiter found a spot where up to 10 sawfish were captured on video in a relatively small area.

SAWFISH FACTS

Once inhabited U.S. waters from Texas to North Carolina, but now only found in Florida

Two species once lived here: smalltooth and largetooth sawfish, but smalltooth are more common

Estimated decline of 95 percent in sawfish population

Threats include incidental hooking and capture in recreational and commercial fisheries; loss of nursery habitat of red mangroves and sea grasses in coastal estuaries because of water quality and development

For more information, go to International Sawfish Encounter Database at Florida Museum of Natural History website or NOAA.gov and search for “sawfish.”

TIPS FOR ENCOUNTERS

State and federal laws prohibit targeting, injuring or harvesting sawfish.

Release sawfish immediately.

Use good judgment and don’t put oneself into danger. Sawfish are large animals that can hurt people.

If hooked or tangled in a line, keep the sawfish in the water — never lift it out of the water and never drag it onto shore.

Cut the line as close to the hook as possible.

Report the encounter to 1-941-255-7403 or email sawfish@myfwc.com.

Researchers believe these marks discovered on the underside of a mature sawfish occurred while it was mating with another sawfish.