From the October, 2010 issue of Florida Sportsman:
Seagrass State of Mind
Restoration efforts improve many grass flats
By Sam Hudson, Associate Editor
In Florida, close to 2.5 million acres of nearshore grassy vegetation produce dynamic fishing from Escambia County, in the far western Panhandle, all the way around the peninsula and north to Volusia County. In South Florida, if you drained away the nearshore waters from the Keys, a snapshot would reveal baseball fields of grass that seem to go on forever. Only the northeastern part of the state lacks significant submerged seagrass, though Spartina and Juncus marsh grasses offer similar estuarine benefits.
In total, at least 70 percent of Florida’s recreational gamefish, prey species and crustaceans depend on seagrasses at certain stages of their lives. Safe to say, all coastal anglers depend on that grassbed bounty in some form or another.
“As a whole, Florida continues to lose seagrass, and seagrass levels are nowhere near historic levels,” says Penny Hall, a research scientist with the Florida Fish and Wildlife Conservation Commission (FWC).
Shoal, widgeon, turtle and manatee grasses—the big four grass species found in most Florida waters—face a slew of factors that can cloud waters and prevent sunlight from reaching their beds. Dredge and fill projects cloud waters and kill grass. So, too, can polluted waste-water runoff, high influxes of fresh water, and nutrient overloads that induce algae blooms. Too a much lesser degree, scarring of flats from boats also damage grass and its roots.
Even some of Florida’s infrastructure mounts a running assault on coastal seagrass beds. The canals which drain Lake Okeechobee east and west—and keep sugar farms profitable—dump phosphorus- and nitrogen-loaded fresh water down the St. Lucie and Caloosahatchee rivers, devastating those estuaries. Historic grassbeds in the St. Lucie estuary system are gone, and any restored oyster beds dieoff when releases are larger.
“Whenever there are discharges, they turn the St. Lucie River into fresh water—which is poison to seagrass,” says Karl Wickstrom, a board member of the Rivers Coalition Defense Fund and founder of Florida Sportsman. “This year was terrible; billions of gallons were dumped during the rainy season.” The Rivers Coalition is funding a federal lawsuit against the Army Corps of Engineers to try to stop the discharges.
When seagrasses aren’t healthy, the whole ecosystem is affected negatively. “It’s kind of a double-edged sword,” says Kenny Wright of Seagrass Recovery, a company that specializes in restoring grass flats and other marine environments. “Healthy meadows are the first line of defense for better quality water and healthier ecosystems. But if water quality degrades, or that’s the initial problem to begin with, the opposite happens and seagrass is lost.” Boom or bust might be a better description.
Studying Seagrass
Extensive studying of at-risk areas across the state continues at the FWC and Fish and Wildlife Research Institutive (FWRI). The good news—those studies reveal that where authorities have resolved water quality issues, some grass beds have shown signs of recovery.
“Tampa Bay was an area of study for awhile, but in the past 20 years we’ve seen an increase in seagrass overall because of heavier regulations limiting runoff,” says Hall.
Newer studies focused on areas to the east and south. “Recent projects include a monitoring program from Jupiter to Biscayne Bay on the uncommon Johnson Seagrass, which only occurs from Sebastian Inlet to Florida Bay,” says Hall. “And we’re also conducting baseline seagrass studies in Florida and Whitewater bays for the South Florida Water Management District concerning the Everglades Restoration Plan.”
Spotlight on Restoration
State and federal authorities can affect water quality positively through increased regulation of runoff and discharges, but there are only so many hands to do the manual labor of re-planting. Many non-governmental players involved in seagrass revitalization handle the grunt work, physically re-planting or prepping the flats for grass growth.
Smaller, nonprofit organizations rely almost strictly on volunteers and donations. Tampa Bay Watch is one such organization, and they’ve re-planted seagrasses and marsh grasses in parts of Tampa Bay including Bishop Harbor, the flats near MacDill Air Force Base and Cockroach Bay.
The Ocean Foundation, a Washington, D.C.-based nonprofit organization involved in marine rehabilitation, recently joined with Columbia Sportswear and Bass Pro Shops to form the Seagrass Grow Campaign ( HYPERLINK “http://www.seagrassgrow.com” www.seagrassgrow.com). The Campaign’s mission is two-fold: inform boaters of the proper way to maneuver around grass beds, and to physically restore damaged beds.
One such flat near Islamorada was the site of the Seagrass Grow’s kickoff demonstration in June. Hip-deep, clear water swayed above turtle grass and pinfish. Sandy trenches from prop scars stitched together the otherwise unspoiled grassy flat. Seagrass Recovery staff Kenny Wright, Beau Williams and Kiel Johnson showed members of the media some techniques they use when hand-planting seagrass into prop-scarred areas.
Transplanting is one basic method, and sometimes it only takes basic landscaping tools. Attach seagrass (that’s taken from a nearby plentiful source) to an oversize sod staple with help from a twist-tie, explained Seagrass Recovery biologist Kiel Johnson. Then set firmly into the bottom. The grass roots take hold quickly, which cuts down significantly on re-growth time—sometimes as quickly as one to two years. “Light prop scars can take years to re-grow naturally,” said Wright, “and severe scars may never grow back.”
Another technique is to lay sediment tubes into the scars as a recruitment tool and base for seagrass to grow. The tubes, filled with sediment from a local source, prevent further erosion from the bed, too. A cotton fabric outer sleeve eventually dissolves, leaving only nutritious substrate and seagrass.
“I’ve seen seagrass growing right on top of the tubes,” said Wright. “When that tube finally breaks open, sometimes seagrass will spill out. Specific seagrasses grow just like our lawn’s St. Augustine grass, with runners looking for places to take hold.”
Sometimes seagrass recovery is so simple, you won’t even recognize it. Captain Alan Sherman, a light tackle guide in Miami, attended the Seagrass Grow demonstration and had an eye-opener.
“There’s a grassflat on the west side of Biscayne Bay, near the Port of Miami, that I can catch seatrout on in the winter time,” he told me. “For the longest time, there were these PVC pipes sticking from the flat and now I realize their purpose.”
Cruising from one flat to another, fishermen might notice such a grouping of PVC pipes in an otherwise empty expanse on a flat. Birds might be perched on them. That’s a technique simply known as the “bird stakes.” The PVC pipes serve as markers not to run over the immediate shallow area, but also create ideal perches for birds to rest and defecate from.
“The bird droppings serve as natural fertilizer over the recovering area of the flat,” says FWC’s Penny Hall. “This technique is especially valuable in the Keys where the bottom is phosphorus limited.”
Sometimes anglers forget how completely entwined nearshore grassy habitat and offshore bottom habitat really are, and that’s why it’s imperative to protect both. The first time I hooked a gag grouper on an artificial lure I was fishing a grassflat near Fort Pierce. A grounded sailboat provided the cover, and I cast my jerkbait toward it, not sure what was going to play. A whoosh of a fish came to the surface and sucked the plastic down.
The fight didn’t have many crescendos, but it was a moment of clarity. After I released the sub-legal grouper, I realized that was probably the last time that fish would feel a hook before heading offshore. More importantly, it was proof positive that grassflats are vital for nearly all Florida gamefish. FS
Success Stories
Successful seagrass recovery continues around the state, and that’s good news for anglers. On the East Coast, areas range from Sebastian Inlet down to Biscayne Bay, and all the way south into the Keys. On the west coast, busy areas in Tampa Bay, Turtle Bay and Charlotte Harbor continue to heal.
Penny Hall points out one success story near Islamorada at Lignumvitae Key that began as an experiment, but turned into a case study.
“We laid pea rock over the banks experiencing erosion,” said Hall. “Once the bank stabilized, we then added sediment tubes to the prop scars. Seagrass began to cover the area within a year and a half.” Hall is now employing this technique at Red Bay Bank off Marathon as well as other locations.
Kenny Wright highlights another section of the Keys that’s seen a remarkable turnaround.
“One area I’m amazed by is the Knight’s Key Bank (near the Seven Mile Bridge at Marathon),” he said. “That area was hit hard by propellers from boaters motoring in from deeper water. About 14 months after we started restoration work, that area has come back and there’s an amazing amount of life there.” Wright says the average time to see revitalization from a repaired grassflat would be at least two years.
Spotlight: Turtle grass (Thalassia testudinum)
Growth: Most common of seagrasses in Florida. Turtle grass grows in maximum depths of perhaps 90 feet, if water clarity allows. Blades can be more than 2 feet tall and about 1 inch wide. Distinguished from other grasses by its wide, flat blade.
Range: Turtle grass ranges throughout most of the state starting at Mosquito Lagoon, heading south, then throughout the Gulf of Mexico. Not present in Northeast Florida, likely due to naturally turbid waters and unfavorable, drastic tidal influences.
About: Name stems from green sea turtles that feed on meadows of this common grass. All manner of inshore species rely on the plentiful flats it creates. Juvenile offshore species such as groupers and snappers, and nearshore fish such as cobia and Spanish mackerel also utilize turtlegrass habitat. Baitfish, crustaceans and other prey are present year-round.
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