- Black sea bass have dangerously sharp spines on their dorsal fin that can puncture human skin.
- The all-tackle world record for black sea bass is 9 pounds, 8 ounces.
- When hooked in deep water and brought quickly to the surface, a black sea bass will often regurgitate its stomach contents.
When a beefy bonefish chomped the shrimp on the end of my line, I took up the slack and gave a stiff jab that would have made Lennox Lewis proud. The bonefish reacted in its signature manner: a blurring burn through the skinny water, causing my trailing line to spew a mini rooster tail. However, the 20-pound test and heavy spin outfit was no match for the tiring bone. I pumped and wound it to the boat in minutes.
Why the seemingly low regard for sportsmanship? Because this wasn’t an ordinary bonefish outing. The game plan was to catch bonefish as quickly as possible to minimize trauma and attach a tag to each. But not your ordinary "spaghetti" tag—this new device involved acoustic telemetry (AT), a state-of-the-art tagging system whereby the tag transmits a signal that’s picked up by underwater listening stations.
Acoustic telemetry listening stations enable researchers to follow the movements of vast numbers of bonefish simultaneously.
Tarpon research is similarly being carried out on a cutting-edge plane. Pop-off archival transmitting (PAT) tags used to track the habits of billfish are now being used on the silver kings. At stake is the opportunity to learn more about two species that, compared to fish with greater food value, receive precious little research attention. The new research may soon provide answers to such basic questions as where tarpon and bonefish spawn as well as migration habits. For example, if tagging data shows that tarpon being netted and slaughtered off Central America are the same fish found off the Gulf and Atlantic coastlines, it will be far easier to convince U.S. lawmakers to put pressure on foreign governments to take action.
One of the leaders in this new-age tagging research is the University of Miami’s Rosenstiel School of Atmospheric and Marine Science (RSMAS). The effort combines conventional tagging techniques with AT and PAT technology. Funding is being provided by Bonefish & Tarpon Unlimited, a non-profit organization dedicated to securing research that will inevitably help those species flourish.
Each bonefish is implanted with an ultrasonic tag that enables researchers to follow its movements from a boat via a receiver on the same frequency called a hydrophone. However, RSMAS researchers are now using new acoustic telemetry (AT) tags that give each bonefish a unique transmitting signature. By positioning listening stations around certain flats, more than 250 bonefish 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 factors—thus eliminating human error.
Each AT tag carries a unique signal to the transmitter, helping identify the movements of individual fish in addition to schools.
“This set-up represents the latest in acoustic telemetry technology, and early results have been very exciting,” says Dr. Jerry Ault, a professor of marine biology at RSMAS and lead scientist for the tagging projects. “Instead of trying to follow fish around in a boat—which tends to spook them and alter behavior—the use of listening stations means I can be sleeping while we are still tracking numerous bonefish movements and habits.”
To cover all the bases and take advantage of both techniques, 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 offer data and also let researchers know that it’s still alive. Nearly 1,000 conventional tags have been implanted thus far, many by fishing guides in Miami and the Florida Keys, as well as by researchers.
I recently went on a tagging trip with Michael Larkin, an RSMAS research assistant under Ault. According to Larkin, the AT data revealed that one particular bonefish returned to the same flat 40 consecutive days. Even four months later, the fish was caught on the same flat, indicating what’s known as site fidelity. However, other bonefish tagged in Biscayne Bay have ended up months later 50 or more miles south in 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 than previously thought. But further research should unlock these mysteries and others.
Conventional "spaghetti" tags still have their place in bonefish research. If a fish swims out of the AT listening station area, it can still offer data and let researchers know that it’s still alive.
A listening station for AT 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 kept below the surface, keeping it out of view to most passers-by while enabling researchers familiar with its general position to visually pinpoint its location. Sites for listening stations are chosen in areas deeper than the surrounding flats to lessen discovery or prop damage, and to maximize the receipt of acoustic signals at the receivers.
The listening station is periodically raised, a probe inserted between a PC and a port in the hydrophone, then all the information is downloaded. The result is a complete record of which tagged fish came to that flat and at what specific times. The next step at RSMAS is to overlay the corresponding conditions at those times concerning tide, temperature, turbidity, moon phase and other factors. At that point, a clearer picture emerges about individual and schooling patterns of behavior.
Pop-Off Archival Transmitters (PATs)
PAT tags for tarpon are even more esoteric. These tags have a timing device that pops off at whatever interval desired, such as six months or a year. The tags then float to the surface and transmit all the stored data to a satellite. This means that tagged tarpon don’t have to be killed and the tag doesn’t have to be retrieved, as is the case with traditional tagging methods.
The benefits over traditional tagging are huge. Previously, you would only know where a fish was first tagged and then where caught, with little information and lots of guesswork in between. But PAT and archival tags don’t require a tagged fish to be re-caught or even the tag retrieved. Meanwhile, an entire minute-by-minute chronology of the fish’s life is being recorded, providing valuable insights into preferred habitats and visitation frequencies at various tides, lunar phases, temperatures, times of day and conditions.
PAT tags will pop off at designated intervals, thus avoiding the need for manual capture of tarpon.
Ault believes the day is drawing closer when we’ll have answers to questions about spawning, migration, feeding habits and other important data that’s missing with bonefish and tarpon.
Plans are on the drawing boards to expand the studies to the Bahamas, Caribbean, Central America and Pacific regions that harbor bonefish populations. And efforts in the U.S. are being stepped up, such as a new, concentrated study utilizing PAT tags off Homosassa, Fla., that’s being funded mostly by BTU member Neal Myers.All the tagging work seeks to engender a deeper understanding of what makes tarpon and bonefish tick, so decision-makers will be more inclined to take the correct steps to protect them.
BTU is also sponsoring an upcoming scientific symposium in partnership with the International Game Fish Association, RSMAS, the Florida Fish & Wildlife Commission and others. The symposium will bring to the table experts from the fishing industry and scientists. BTU expects to have enough accumulated data by the time of the symposium to present a detailed report on the tagging efforts. The symposium takes place January 9-11 at IGFA headquarters in Dania, Fla., with Dr. Glenda Kelley serving as symposium director.
But the tagging studies using PAT and AT tags present challenges: Costs for tags and research work are high, and the coordination necessary to get the tags into fish can be complicated. But this new technology has moved tagging efforts out of the silent-movie era to the point that a new door has been opened to a data stream that is destined to revolutionize our knowledge of silver kings and gray ghosts. And that all points to healthier and greater resources for those species in the future.
Sidebar: Lend A Helping Hand
Bonefish & Tarpon Unlimited is the only non-governmental group funding these studies. The tagging projects are gaining momentum and already beginning to fill in the knowledge gaps. But more PAT and AT tags must be implanted in order to obtain a rich flow of data to analyze.
BTU’s membership boasts renowned personalities such as Stu Apte, Billy Pate, Chico Fernandez, Lefty Kreh, Curt Gowdy, Guy Harvey, Johnny Morris, Mina Hemingway, Norman Schwarzkopf, Joan Wulff, Mark Sosin and even EPA Administrator Christie Whitman. To learn more about BTU and how to join the effort, call 813-546-8241 to obtain a brochure and newsletter.
Doug Kelly is a freelance writer and former editor of Sport Fishing magazine. Kelly also serves part time as Executive Director of Bonefish & Tarpon Unlimited.