Welcome back to the inaugural Tarpon Week! In this feature, we sat down with JoEllen Wilson, Bonefish & Tarpon Trust’s Juvenile Tarpon Habitat Program Manager. BTT is deeply engaged in improving bonefish, tarpon, and permit fisheries and habitat through science and advocacy. For a species like tarpon that has enjoyed a great deal of angler-led conservation here in the states, quality habitat is absolutely critical for a healthy population today and long into the future.
It’s no secret that tarpon habitats throughout Florida are under extreme stress from both climate-driven impacts, development, and pollution. That’s why BTT created the Juvenile Tarpon Habitat Initiative. These baby tarpon are the future of the population, but the mangrove habitats they rely on are disappearing at a concerning rate. This BTT initiative seeks to better understand that and turn the tide. Follow along for more on BTT and JoEllen’s critically important work.
Flylords: Introduce yourself! How did you get involved with BTT and fisheries science?
JoEllen: I started working for BTT in 2009 as the first Membership Administrator. Dr. Adams, the Director of BTT at the time, gave a presentation to my college ichthyology class about the need for volunteers. I volunteered with sampling for a few months and joined the organization once the position became available. After a few years as an MA, I was ready to go to graduate school to continue my scientific education, and the next BTT-funded project was juvenile tarpon habitat use. In 2014, upon graduating, BTT re-hired me as the Juvenile Tarpon Habitat Program Manager.
Flylords: So you are leading BTT’s juvenile tarpon habitat initiative–tell us about this work.
JoEllen: When I started the initiative, we were learning the ins and outs of early life history habitat metrics for juvenile tarpon, since it wasn’t well documented in the scientific literature, to create a template of functional nursery habitat. That research led to a framework of nursery habitat conservation measures, including protecting natural habitats and restoring degraded habitats in order of priority. Over a decade later, our main focus is on integrating habitat into fisheries management plans and finding other innovative ways to conserve tarpon nursery habitat.
Flylords: As fishermen, we acutely understand the value of habitat to sustain fish populations and provide actual fishing opportunities. Can you shed some light on the different habitats tarpon utilize?
JoEllen: Tarpon use a coastal habitat mosaic throughout their life cycle, including embayments, backwater coastal ponds, and mangrove-lined tidal creeks as juveniles, estuarine coastlines and rivers as sub-adults, and coastal and offshore habitats as adults. Tarpon don’t mature until about 8-10 years old and live up to 80 years, so the adults that anglers are fishing for are likely decades old. That means that the impact that we’ve seen on juvenile habitats 20 and 30 years ago is just starting to impact the fishery.
Flylords: What about how these habitats are changing? What are the causes?
JoEllen: In Florida, especially, we’ve seen a substantial loss of our marsh and mangrove habitats and even bigger impacts to our water quality. These are effects from nutrient and contaminant runoff, pharmaceuticals leaching from septic tanks in coastal communities, changes in natural watershed flows, and coastal development causing habitat loss. We’ve already lost about 50% of mangrove habitat, which means about 50% of juvenile tarpon habitat.
Flylords: And why are quality habitats so critical to juvenile tarpon? What does the perfect nursery habitat look like?
JoEllen: A tarpon’s reproductive strategy is to produce many in the hopes that a few will survive. They spawn offshore with trillions of eggs, and a small percentage of those will eventually become larvae. The larval stage lasts about 30 days as they make their way from offshore back into the estuaries, and a fraction of those survive. Luckily, juvenile tarpon have evolved to inhabit some of the most inhospitable places with high water temperatures, salinity swings, and low dissolved oxygen levels bordering hypoxia.
But these juvenile tarpon habitats are dwindling because they’re in close proximity to human impacts. We know from previous research that just because we find juvenile tarpon in these habitats, it doesn’t mean they’re functional habitats. Often, we’ll get calls from anglers finding juvenile tarpon in ditches and golf course ponds that larvae can access during storm events, but don’t allow for tarpon to emigrate and rejoin the spawning population. They’re pretty much stuck with limited prey in a confined space. In the early days, we partnered with guides, anglers, and homeowners to identify juvenile tarpon habitats and characterize them as natural or altered. The natural habitats are innately the most productive.
We then recommended the natural habitats for protection and used a ranking system to prioritize the degraded habitats for restoration using factors like feasibility, biology, and connectivity. If we’re going to recommend habitat restoration as a means to combat habitat degradation and loss, we first need to know if it works. BTT tested three variations of juvenile tarpon habitats using characteristics that we observed in natural nursery habitats. We found that a shallow meandering tidal creek system with vegetative edge and connectivity at high tides produced juvenile tarpon with the fastest growth, while the design with constant connectivity and a 2m deep depression had the highest emigration rate.
Flylords: What’s been your/the Initiative’s focus as of late? I know you all have been devoting a lot of time and energy to Charlotte Harbor.
JoEllen: Charlotte Harbor/Boca Grande is known as the Tarpon Fishing Capital of the World, so it makes sense that we’d have a large tarpon conservation effort in this region. BTT currently has six potential juvenile tarpon habitat restoration sites in the area undergoing preliminary design, with permitting and restoration to follow. The other benefit to working in Charlotte Harbor is the many agencies – federal, state, and local – that are willing to partner on tarpon conservation projects. BTT is collaborating with these agencies to create an integrative map that can guide future development in Charlotte County with juvenile tarpon habitat in mind.
Flylords: Tell me more about how this initiative stands to benefit other fisheries or wildlife species?
JoEllen: The benefit of this research is that it is repeatable in other regions for juvenile tarpon and can also be adapted to different habitats and focal species. For example, we’re identifying and quantifying juvenile tarpon habitats, but this same framework can be used for a terrestrial species in upland habitats. Additionally, protected or restored juvenile tarpon habitats also support many other species with similar habitat needs. Like snook, for instance.
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Flylords: How can anglers get involved and support this work?
JoEllen: BTT relies heavily on the involvement of anglers and guides to provide knowledge and input on our research. We are still collecting juvenile tarpon locations (tarpon 12” and under) to add to our database, and all sites are kept confidential. We also appeal to residents in coastal communities to be a voice for habitat, which includes converting septic tanks to sewer and advocating for upgrading treatment facilities, foregoing lawn fertilizers, especially in the rainy season, developing in ways that leave natural water flows unaltered, and keeping mangrove habitats intact. Without healthy habitats, we won’t have healthy fisheries.
Cover picture photo credit: Pat Ford
