January 29, 2019
From the February 2019 print issue, on newsstands now. Click here to subscribe.
Snook and tarpon habitat right under our noses can be reclaimed.
Some of the best conservation ideas are simple to execute, inexpensive to maintain and hiding in plain sight. What they require are the grounds to make them happen, literally and figuratively, and partners willing to share the work.
Consider the amazing success of the unassuming Bee Gum Reserve habitat in Indian River County. Working in partnership, Indian River Land Trust, Bonefish & Tarpon Trust and a team from Florida Institute of Technology, led by marine biology Prof. Jon Shenker, turned a pedestrian mosquito control impoundment on the North Indian River Lagoon back into a productive nursery for snook and tarpon. By so doing, they provided a model for the rest of the state to follow to improve gamefish habitat in similar terrain.
As Aaron Adams, Director of Science and Conservation for Bonefish & Tarpon Trust says, “Without the habitat where young snook, tarpon and other gamefish grow up to become adult fish, traditional fishery management won't have the stocks to manage. Not only should we protect and preserve our gamefish habitat, but we need to incorporate managing fishery habitat into traditional fishery management tools.”
This tract of land had in fact been slated for residential development by its previous owner.
The story of how these teams were able to increase the nursery's productivity in those shallow mangrove marshlands and add to our stocks of valuable gamefish is one of resiliency, vision and ingenuity—and the generous cooperation of the Indian River Land Trust who bought the property years ago.
The Bee Gum Reserve at the west end of Fred R. Tuerk Drive is tucked just off A1A in Indian River Shores, a stone's throw from high-volume traffic and pricey homes. Driving by, you likely wouldn't even know it's back there or that it's a mosquito control impoundment. The 111-acre nature preserve was purchased by The Indian River Land Trust in 2011 for $4.25 million through private donations and a $3 million land trust loan from The Conservation Fund, a Virginia-based organization that helps pay for the purchase of lands vulnerable to development. The tract of land, which reaches into the lagoon, had in fact been slated for residential development by its previous owner, says Ken Grudens, executive director of the Indian River Land Trust.
“This habitat is within miles of hundreds, if not thousands of homeowners,” says Shenker of FIT, “and there are habitats like this all up and down the Indian River Lagoon and around the ?????????state. If people went into their backyards, they would discover habitats like this that they haven't paid much attention to in the past.”
“The property is literally for the birds,” said Grudens. The land is part of the Atlantic Flyway, a major corridor for migrating birds each year.
“After we purchased the property to preserve it,” Grudens explained, “we had organizations coming to us with ideas on how to improve its conservation use, and we realized what an opportunity we had. Aaron and Jon had some ideas on how the nursery habitat here could be improved to let more snook and tarpon back into the estuary, and once they explained it all to us and the scientific studies they planned, we got on board.”
Part of what makes the waters in Bee Gum and other marshy, mangrove lined channels so attractive to young gamefish are the low oxygen levels—which prevent bigger, predatorial fish from hunting there and allow the young ones to safely grow. However, those same swampy conditions make the waters prime for mosquito propagation, so in the 1800s, settlers around the state turned great tracts of such marshy lands into mosquito control impoundments. Dikes were built around the mangrove and Spartina grass swamps to control water flow, and those impoundments were flooded to restrict mosquitos' access to shallow waters, which they need to breed successfully. When managers realized that the grounds were no longer serving as nursery habitat for gamefish either, they installed culverts that could be opened and closed to give and take access to the estuaries from the impoundments. However, in mosquito season, the culverts were closed to allow the impoundments to remain at high water levels to inhibit mosquito breeding.
Adams at Bonefish & Tarpon Trust and Shenker at Florida Institute of Technology had some ideas on how to measure the productivity of those nursery habitats, improve them and—importantly— verify those improvements so that the Bee Gum project might be used as a model for similar mosquito control impoundments around the state.
“In 2014, I had a science position at Florida Tech working with Jon,” Adams said, “and we started interacting with the science staff at the Indian River Land Trust, and it became apparent that we could improve their habitats as nurseries.”
Adams designed the study to insert microchip tags into young fish and track their movements via a series of antennas installed around the culverts. Each antenna is hooked up to a data reader and a solar power source. The FIU team caught, tagged and released over 350 young snook and over 105 juvenile tarpon from the impoundment after implantation with the passive integrated transponder tags (PIT) tags. Survival rate was 100 percent. When the fish passed through the culverts, researchers got the beep from the fish leaving the nursery, just like a car passing through a toll booth on the highway. “This system gives us a really good understanding of where these young fish are going and when,” said Shenker.
“The basic idea was pretty simple,” said Shenker. “Tag a bunch of fish and figure out where they're going, and when they're going. Our initial idea was that the fish would be trapped in the summer and in the fall when they opened the culverts up, all the fish would go flooding out.”
However, the team found that when the culverts were opened in the fall and winter, the young fish didn't leave the nursery habitat.
“From our studies of nursery habitat over in southwest Florida,” Adams said, “we knew that juvenile fish instinctively left the nursery in the summer months to join the estuary waterways and the greater stocks of breeding adults, but here at Bee Gum, they couldn't, since the culverts were closed. We worked with the Indian River Mosquito Control District here on this property, and they agreed to alter the schedule of opening and closing of the culverts to see if we could find a way to get a better emigration of young fish into the estuary.”
During a recent spring when the culverts were about to close to resume mosquito control, the researchers noticed that the juvenile fish were starting to leave the impoundments. The Indian River Mosquito Control Board agreed to perform a drawdown of the impoundment system. “They opened the culverts for a couple of days in July, and let the waters remain low for about a week,” Shenker explained, “and then they closed them again and pumped water back in to prevent mosquito breeding.
“Within the first 36 hours of opening up these culverts,” Shenker continued, “snook after snook after snook after tarpon all went flooding out of the impoundments. We saw more fish flooding out of the impoundments in two days than we saw leaving over the entire previous winter, and that was really encouraging. It worked like a charm.”
The fish, the researchers observed, jumped at the chance to leave the impoundment. In that first drawdown, they recorded more than 30 snook and nearly half the tagged tarpon leaving the impoundment. “It was like a checkout line,” said Adams, “just as we'd suspected.”
“We're on our way,” added Shenker, “to developing an inexpensive modification to the standard mosquito control management that can truly improve tarpon and snook populations in the Indian River Lagoon and elsewhere, as well. The lesson that we want to pass on to others is that if you can manage these habitats according to the biological rhythms of what the fish are doing, then you stand a really good chance of boosting up their survivorship for the next generation.”
Adams of Bonefish & Tarpon Trust adds that the big picture has to do with better fisheries management. “We were able to use information from snook and tarpon in Charlotte Harbor and apply it here, where with our team, we experimentally revised how the water management here at Bee Gum could be changed to improve the nursery habitat. Now the plan is to take this success to other altered habitats to figure out how to best manage them so that once again they are productive nursery habitats for snook, tarpon and other species that have huge economic value to the state of Florida.
“Another one of our big picture goals with this,” Adams concludes, “is to work with the state of Florida to incorporate habitat into fisheries management. Right now, the Department of Environmental Protection manages habitat and FWC manages the fisheries. We all know that fish depend on healthy habitat and if we can work with the state to increase the value of habitats like Bee Gum and other impoundments to make them more valuable, that's going to help them manage the fisheries.
“One of the best things that people can do to help us at Bonefish & Tarpon Trust with projects to protect habitat, is to tell us where they find these juvenile fish,” Adams said. “These are important habitats and we can add them to our habitat map, visit them and characterize them on our list of healthy habitats to protect and degraded habitats to restore. And don't worry, we will not share the locations. We're all anglers, and we know that fishing spots are sacred. As a matter of fact, that information that is shared with us is never shared outside Bonefish & Tarpon Trust.” FS
First Published Florida Sportsman Magazine February 2019
Also in this months issue...
Notes on the Turkey Call
By Ian Nance
The traditions, craft and magic of calling in those big birds.
Show Me the Way
By Mike Conner
The mystery and allure of Florida backcountry navigation through the years.
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