Biologists slowly ridding the Braden River of tape grass

Kristen Peterson, a biologist with the Florida Fish and Wildlife Conservation Commission, needed an airboat to traverse the Braden River in August 2023.

Old World Tape Grass had taken over, leaving the river unnavigable. Smaller, less powerful boats were getting stuck in the dense vegetation. 

On July 15, the Braden Lady, a pontoon boat, and the Braden River Queen, a Duffy electric boat, took off from the dock at Jiggs Landing. The tour boats set out across the Bill Evers Reservoir and went up the Braden River. 

The passengers were from all over the country, but were not the typical tourists. Denise Kleiner, the general manager at Jiggs Landing, lent the boats and captains to Peterson for the morning, so Peterson could show a group of graduate students the invasive tape grass. 

The students were in the area attending the Aquatic Plant Management Society’s annual conference in St. Petersburg. 

Neither the pontoon nor the smaller Duffy had any trouble traveling the river, but Peterson said the tape grass is only about 25% better since the FWC started treating it with liquid copper and an aquatic herbicide called Diquat last year.

A neighbor spotted Peterson on the pontoon. She yelled from her dock, “We were out here for four hours yesterday.”

Peterson said residents in the area do “yard work” on the water. She’s sat down with them, so they know what they can and can’t do. The most important rule is to only collect what’s floating. Then, the tape grass gets bagged like any other weed and stuck on the curb for pickup. 

There are signs of progress, though. Peterson plucked a clump of the slimy grass out of the water and held it up to show the students its roots.

“The roots are orange,” she said. “Some of the blades are brown.”

Photo by Lesley Dwyer

White roots would be a sign of health. While the grass isn’t completely brown and dead, it’s no longer white, green or thriving and getting caught in boat motors. 

Peterson said it only took about six months for the grass to completely blanket the river.

Part of what makes the grass so interesting to a group of plant management students is that tape grass is a “cryptic plant." It has a lookalike in the native eelgrass, which makes it tougher to control. 

Genetic testing is the only way to definitively distinguish one from the other. However, Peterson has spent over a year collecting and examining samples. 

Non-scientifically speaking, she told the students that it just looks "sketchy."

There are no additional herbicide treatments scheduled right now, but Peterson said another treatment will likely be needed.