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Deciphering the Dynamics of the Tarpon Fishery
BTT’s new study reveals threats and inspires solutions to Florida’s tarpon decline.
By Chris Hunt
A depressing cocktail of threats continues to bear down on South Florida’s tarpon fishery, according to an ongoing study by Bonefish &Tarpon Trust. But, according to Dr. Aaron Adams, BTT’s Director of Science and Conservation, the distressing information coming from the study is arriving with a silver lining of hope.
“We have to identify these problems so we can have access to the solutions,” said Adams. “And the solutions are going to lie with the fishing community in Florida. We have to protect the fishery because nobody else will.”
The new study was in part inspired by a recent, less formal online survey of Atlantic tarpon anglers conducted earlier this year. The survey of about 1,000 anglers revealed that the fishing community is just as alarmed by the decline in tarpon as the scientific community. It drew upon the experiences shared by tarpon anglers and showed that the perception that fishing now is not as good as fishing was in the past.
The new study proves that anglers’ perception is a troubling reality.
Steve Lombardo, BTT’s postdoctoral associate who is leading the study, is compiling reams of existing data from a wide variety of sources and mining it for information that might offer clues behind South Florida’s flagging tarpon populations. The idea, Lombardo says, isn’t to validate the belief by the fishing community that tarpon fishing is in decline. He’s trying to get at the possible sources behind the diminishing fishery for the ultimate purpose of applying the information to potential solutions.
KEYS GUIDES VITAL TO FINDING CAUSES OF DECLINE
Lombardo’s analysis is leaning heavily on guides in the Florida Keys. He wants to turn their years of anecdotal tarpon-fishing experience into real spatial data that can be used in combination with the other data he has in hand to sleuth out the “why” behind the decline.
“The guides are probably our most active resource in this effort,” Lombardo said.
For instance, project collaborator Brooke Black interviewed guides, which included them drawing maps of their dependable fishing grounds as far back as they can remember. They drew these maps in five-year periods, from when they started guiding to present day.
“We’re still analyzing data, but by just looking at the maps it’s easy to see that the tarpon fishing grounds have contracted,” Lombardo said. One set of maps from 1997 to 2001, for example, shows that fishable areas shrank by about two-thirds.
There are reasons for the contraction, both known and unknown, Lombardo said. Guides are on the water daily, and they’re seeing a rampant uptick in boat traffic, and in irresponsible boating in areas important to tarpon. And, Lombardo said, the number of anglers is up significantly, too.
HABITAT CONTINUES TO DECLINE
Whether it’s degraded due to poor water quality, unusable by tarpon thanks to a dramatic increase in boat traffic, or simply becoming too warm due to global climate change, suitable habitat for Florida’s tarpon seems to be diminished.
And, Adams said, the sense of urgency to address the causes of the habitat decline is acute.
“People tend to think of a decline as something that takes place gradually over time, over a long-term trend line,” he said. “That’s not the way it happens in nature. Most often, we see not much change or just a small decline, but then the system hits a threshold, and things kind of fall off a cliff. Urgency is extremely high.”
And, Adams said, while it’s tempting to search out a single smoking gun to blame for the decline, that’s not a practical approach. Conversely, the “put a Band-Aid on it” approach isn’t workable, either. While on-the-ground restoration work has its place in the broader scope of things in the Keys and elsewhere, it’s expensive and requires groups like BTT to navigate a morass of bureaucracy that is counter to the urgent timeline.
Also, Adams said, restoring cherry-picked locations may not even take hold, given the vast number of environmental issues facing the Keys.
“It would be like giving a lung transplant to someone who won’t quit smoking,” he said. “First we have to identify the causes, and address them, before we entertain ideas on restoration.”
SPATIAL CONSERVATION
That’s where Lombardo’s analysis comes in. Lombardo has gathered data from a host of sources ranging from the state of Florida, the National Park Service, regional universities and even county governments. This information is giving BTT the clues it needs to help educate the regional community and address the threats to tarpon head-on.
And to be clear, very little, if any, of the information Lombardo is gathering is specific to the fall in tarpon numbers. Rather, it includes data on a wide array of topics, like the numbers of active septic systems in the Keys, water quality test results stretching back decades, vehicle traffic crossing into the Keys, boat launch data, satellite photos, and historic air and water temperature data.
When viewed separately, the information might seem arbitrary. But, by being combined in a spatial analysis using GIS technology, the data can tell a story.
“It’s a data-intensive study,” Lombardo said. “It’s showing that we can’t just put a finger on one cause. It’s showing us that we need to consider the big picture. Yes, we can prioritize, but we have to do it with the big picture in mind.”
By looking at the tarpon population drop-off through a spatial conservation lens, BTT can consider all the factors that, when brought together, can offer substantive information about the decline. Also, by parsing the data through GIS mapping technology, Lombardo can identify each item independently and determine where the impacts are most acute.
From a preliminary perspective, Lombardo can see where threats initiate, where they overlap and where they actually hit tarpon where it counts—their habitat.
THE CAUSES ARE MANY
Lombardo’s data is affirming what anglers—particularly guides— already knew. There is more boat traffic, and many boaters are unaware that their activity is harmful to Keys tarpon. Aerial photos showing thousands of propeller scars sliced across the grass flats tell a compelling story about irresponsible boat traffic and the human impact on habitat.
There is also more fishing pressure. And this pressure is being put on a smaller area where tarpon are still found in the Keys. This pressure, of course, likely results in more anglers using tarpon migration chokepoints to catch fish. And, in turn, may result in higher tarpon mortality for released fish from sharks that have learned to gather where anglers congregate.
But there are other causes, too, that might not be top-of-mind for guides and anglers. Take, for instance, the fact that global climatic changes have caused average water temperatures in the Keys to rise three degrees Celsius (5.4 degrees Fahrenheit) in just 20 years. Over the summer of 2023, water temperatures in some locations in Southwest Florida and the Keys topped 100 degrees Fahrenheit.
That record warm water plays a significant role in the die-off of seagrass, coral bleaching and algal blooms that rob seawater of oxygen. It forces fish to go elsewhere, where temperatures are cooler and more tolerable.
Another cocktail ingredient that is being addressed is wastewater treatment in the Keys. Progress has been made in the conversion from septic systems to a central sewage system. But it will take some time for the legacy of decades of septic systems to completely fade. And some of the central-system sewage effluent is being injected into the ground in shallow wells, which, recent research has shown, bubbles back toward the surface pretty quickly. Fortunately, the shallow wells should be replaced with deep injection wells, which will help to alleviate this problem.
Even Adams, by all counts an optimist, concedes that the use of spatial conservation tools can make it look hopeless because it can make the challenges seem overwhelming. But, he counsels, it’s not hopeless, so long as stakeholders remain involved and are willing to put in the work.
“The spatial management approach is common in the terrestrial world,” Adams said. And, yes, he admits, right now the story appears as if it’s from the horror genre. But having the information at the fingertips of anyone who wants to access it, from biologists and anglers to agency staff to politicians, gives everyone a chance to read the whole story.
“Spatial conservation gives us the chance to prioritize, and address the issues facing habitats that might deserve more attention to start,” Adams said. For instance, he said, armed with this spatial data, managers at the Florida Keys National Marine Sanctuary might be able to use it to better manage boat traffic or to address other threats in certain areas of the sanctuary.
EDUCATION
Putting the spatial data to use is, of course, the ultimate goal. That’s why Lombardo and Adams insist that education is key to any solution to South Florida’s tarpon challenge.
“I think the fishing community sees the bigger picture,” Adams said. “The guides are not only leading the charge in spatial management, they are also a big part of the science that is informing conservation efforts.”
In the end, Adams said, it’s going to come down to the fishing community—in other words, all of us.
“The solution is going to require engagement in public policy, and that means the fishing industry is going to have to continue to engage,” he said. With the spatial data still in production by Lombardo and others at BTT, the information will be there for anglers, boat builders, rod manufacturers, tackle dealers … Everyone will have access to the story.
And, ever hopeful, Adams hopes they’ll help write the conclusion. It doesn’t have to be a horror story. It can be the tale of an amazing comeback.
For the tarpon’s sake, let’s hope so.
Chris Hunt is an award-winning freelance journalist and author and an avid fly fisher based in Idaho and Florida. He writes frequently about conservation, fly fishing and travel. His most recent book, The Little Black Book of Fly Fishing, is available online and at finer bookstores.
