AS SEEN IN THE WINTER 2004 ISSUE

Thanks to new efforts utilizing satellites and technologically advanced transmitters, our understanding of bonefish and tarpon behavior is taking on a whole new shape.

Remember in years past how your eyes would glaze over and your mind would drift as soon as the topic of fish tagging came up? Jabbing what appeared to be red swizzle sticks into the backs of fish and waiting months, years and often times never, for anglers to re-catch the tagged gamesters seemed like heady stuff.

 No one other than marine biologists really gave tagging more than a second thought; well times have changed. With advances in aquatic transmitters and the use of space age technology, tagging methods have evolved far beyond the simplistic practices of yesteryear. That’s raised a new level of excitement among researchers and shallow water anglers alike.

Couple the research advances with a need to fill in the missing pieces about bonefish and tarpon behavior, and you can understand why a new organization was formed. Titled Bonefish & Tarpon Unlimited, the Key Largo based non-profit organization boasts most of the world’s greatest international fishing legends. The BTU roster includes the likes of Stu Apte, Billy Pate, Sandy Moret, Chico Fernandez, Gary Ellis, Amy Knowles, Rick Ruoff, Rick Murphy, Lefty Kreh, Mark Sosin, Larry Dahlberg, Chico Fernandez, Mina Hemingway, Al Pflueger, Bob Stearns, Guy Harvey, Joan Wulff, Curt Gowdy and many more. The group also boasts movers and shakers from the worlds of science, business and the marine industry. It’s an unprecedented partnership of on-the-water expertise and marine scientists that’s provided a basis for eventually achieving Buts mission: enhancing and preserving present and future stocks of two of the most sought after, glamorous inshore species.

Why is there a need to learn so much about two particular species that are released anyway? As important as tarpon and bonefish are to tourism and the industries they support, we know surprisingly little about them. No one really craves a bonefish sandwich or a sautéed tarpon fillet, so both species get short changed compared to snapper, grouper, mackerel, tuna and others that represent “food fish” that end up in markets and on restaurant menus across the state. Therefore precious few dollars flow from the government or foundations to sponsor research programs focusing on tarpon and bonefish. The result has been a mere trickle of data on even basic behaviors such as spawning locations and migration patterns. Were you aware that bonefish, a species that spends most of its adult life in water only inches deep, spawn offshore in depths ranging to hundreds of feet?  

Fortunately, new research efforts by groups employing modern technology, such as Bonefish & Tarpon Unlimited, are beginning to provide answers that can lead to changes in how we manage these precious species. For example, if tagging data proves that tarpon being netted and slaughtered off Central America are from the same schools of fish found off the Gulf and Atlantic coastlines, it will be far easier to convince U.S. lawmakers to apply pressure on foreign governments to take action. After all, if fewer fish end up in our waters, that inevitably impacts the seven billion dollar a year sport fishing economy and we all know that in Washington, money talks.

To help fill in the missing pieces of the puzzle, Bonefish & Tarpon Unlimited fund research partners such as Dr. Jerry Ault at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, Dr. Aaron Adams of Mote Marine Laboratory in Sarasota, Dr. Jon Shenker of the Florida Institute of Technology in Melbourne, and Dr. Michael Domeier at the PIER Institute in San Diego.

Adams is conducting juvenile bonefish studies throughout the Florida Keys with the assistance of professional guides who have a stake in ensuring greater and healthier fish populations. Two sub-species of bonefish have already been identified based on DNA analysis, and breakthroughs are expected on recognizing nursery habitat and ecosystems that may be more conducive to faster growth. Farther up the coast, Shenker has been taking seine-netting samples in estuaries around the Melbourne area and the Indian River Lagoon System. He’s found tarpon larvae and juveniles only inches in length, helping him form a much needed model on the unknown early lifecycles of “poons”.

One of the more advanced techniques for learning about habits of gray ghosts involves Acoustic Telemetry (AT). This technique initially involved using a boat to follow  bonefish implanted with an ultrasonic tag. Researchers would hold a receiver, called a hydrophone, in the water. The hydrophone was tuned to detect the frequency of the tag. The problem is that fish were more often than not lost during the pursuit or so spooked that their behavior was far from normal.

However, a newer, more convenient approach to acoustic telemetry has allowed hydrophone listening stations to instead be situated around certain flats or channels. Instead of having to follow bonefish in a boat, the listening stations pick up each tagged bonefish’s unique transmitting signature. In this fashion, more than 250 fish can be tracked at the same time. This offers unprecedented data on movements of schools as well as individual fish, revealing preferred tides, moon phases, water temperatures and other pertaining factors thus eliminating human error. “Early results have been very exciting,” says Ault. “The use of stationary listening stations means I can be sleeping at night while we’re still tracking numerous bonefish movements and habits.”  

           A listening station for acoustic telemetry tags entails a hydrophone chained to a 5-gallon bucket of cement with a small buoy attached. The length of rope is adjusted so the buoy is suspended just below the surface. This keeps it out of view to most passers-by while enabling researchers familiar with its position to pinpoint its location. Sites for listening stations are chosen in areas deeper than the surrounding flats to lessen discovery and prop damage, and to maximize the receipt of acoustic signals at the receivers.

           Listening stations are periodically raised above water where a probe is inserted between a personal computer and a port in the hydrophone. The information is then quickly downloaded. The listening stations are reset in strategic positions that capture movements of bonefish carrying the acoustic transmitters. The result is a complete record of which tagged fish came to that specific flat and at what times. The next step is to overlay the corresponding conditions at those times concerning tide, temperature, turbidity, moon phase and other factors. At that point, a clear picture emerges about individual and schooling patterns of behavior.

To cover all the bases, each bonefish implanted with an AT tag also receives a conventional tag. In this way, if a fish swims out of the listening station area it can still be captured and provide data, as well as let researchers know that it’s still alive. Nearly 2,500 conventional tags have been implanted thus far, which has involved the cooperation of numerous fishing guides and anglers throughout Miami and the Florida Keys. This conventional tagging is also being carried out at several bonefish camps in the Bahamas under the supervision of Bonefish & tarpon Unlimited researchers, with future plans to do the same in the Caribbean, Central America and South Pacific.

Results of AT and conventional tagging are already changing traditional views of bonefish behavior. One particular bonefish implanted with an AT tag returned to the same flat on 40 consecutive days. 120 days later, the fish was caught on the same flat, indicating what’s known as site fidelity. However, another bonefish tagged in Biscayne Bay reappeared months later about 100 miles south in the heart of the Florida Keys. These differences indicate that bonefish site fidelity may be related to their size or the time of year, and there is a greater degree of stock mixing and migration than previously thought. Further research now underway with a greatly expanded AT program should unlock these mysteries.

Pop-up Archival Transmitting (PAT) tags for tarpon represent an even greater use of state-of-the-art technology. PAT tags, shaped like a stage microphone, contain a timing device that allows them to detach from the fish and float to the surface at a predetermined interval, such as three months or up to a year. The tags then transmit all the stored data to an Argos satellite. The data in turn is downloaded to a laptop at the research lab and then deciphered with a sophisticated software program.  

The benefits over traditional tagging are huge. Previously researchers only knew where a fish was first tagged and then caught, with little information and lots of guesswork in between. But PAT tags don’t require a tagged fish to be recaptured or even the tag retrieved. Meanwhile, an entire minute-by-minute chronology of the fish’s life is recorded, providing insights about preferred habitats and visitation frequencies at various tides, lunar phases, temperatures, times of day and conditions.

Ault, Domeier and others have implanted dozens of tarpon with PAT tags. At first, only about 10 to 20 percent of the tags stayed on the fish, but recent efforts with better tagging and releasing techniques and a shorter interval for releasing the tags have moved that figure above the 50 percent mark. In May, Ault tagged seven large tarpon off Veracruz, Mexico. Thus far two of the tags popped up hundreds of miles away off the coast of Texas. An indication that silver kings indeed migrate between the two countries. On a different occasion, two tags popped up within five miles of each other off Florida’s Sebastian Inlet. They had originally been implanted on tarpon off North Carolina, possibly pointing a finger at a spawning location; further tagging may prove this.

Ault believes the day is drawing closer when we’ll have clear answers to questions about spawning, migration, feeding habits and other important data that’s missing with bonefish and tarpon. All the tagging efforts seek to engender a deeper understanding of what makes tarpon and bonefish tick, so decision makers will be better able to take the correct steps to protect the species.

In addition to the tagging programs, Bonefish & Tarpon Unlimited has co-sponsored the first series of symposiums focusing exclusively on bonefish and tarpon, with entities such as the International Game Fish Association, Tarpon Tomorrow, the Florida Fish & Wildlife Conservation Commission and others. BTU brings to the table experts from the fishing industry and scientists from around the world who specialize in the two species. Last October, Bonefish & Tarpon Unlimited and the University of Miami organized what’s believed to be the first bonefish census ever conducted in a large area; in this case South Florida. The result is an estimated population of over 300,000 bonefish, which will serve as a baseline for annual censuses so we can do more than guess if the resource is declining, remaining constant or growing larger.

Even so, the strongest research goals still rely on increasing the quantity and quality of the tagging studies. However, the use of AT and PAT tags present challenges: Costs for tags are $350 for each AT tag and $3,500 for PAT tags along with $1,000 for each listening station. In addition, costs for related research work are high. Plus, the coordination and logistics necessary to get the tags into fish can be complicated and time-consuming.

Chairman of BTU Tom Davidson says, “Despite the costs and difficulty in moving through uncharted waters, the new technology in research programs has helped elevate tagging efforts from the silent-movie era to a point where a new door has been opened to a data stream that is revolutionizing our knowledge of tarpon and bonefish.” All that points to increasing the odds for greater populations of Kings & Ghosts in the 21st century.


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How You Can Help
          One of the mainstays of Bonefish & Tarpon Unlimited’s ability to start and sustain tagging programs is its membership. Now totaling nearly 600 members worldwide, anglers passionate about enhancing and preserving future generations of these treasured species can join the organization for as little as $25 per year.

Many members help with tagging efforts directly or take part in tagging expeditions. To review the benefits for the various membership levels and to learn more about Bonefish Tarpon Unlimited, visit www.tarbone.org or contact dkelly@tarbone.org.

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Bio
Doug Kelly is an International Game Fish Association representative and former editor and columnist for several magazine and newspaper publications. Doug currently serves as Executive Director of Bonefish & Tarpon Unlimited. For more info on the organization, please contact Doug at dkelly@tarbone.org.

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