There is a great deal of unregulated and unreported fishing activity around the world, all of which is threatening not only individual species of fish but entire marine ecosystems as well. While most everyone agrees that conservation measures are necessary in many areas within international waters, there is a lot of disagreement about exactly what should be done – or where, when and how these measures should be implemented.
Marine conservation in any form can be a complicated process. However, when it comes to migrating marine animals, the challenge of creating conservation management solutions becomes even greater. After all, no one owns these roving sharks, tunas or marlins. And, when these fish swim out of a particular country’s Exclusive Economic Zone and into international waters, whose responsibility is it to manage them? Do any countries or organizations even have the legal authority to do so?
Those are fair questions, but we need more information before we can get to the point of creating and enforcing protective measures – after all, marine conservation is a process, not a knee-jerk reaction. The first step in the process is to learn more about the species that are in need of protection, such as their behavioral habits, migratory patterns and so on. Armed with that data, we can then formulate useful, responsible conservation policies and enforcement measures to protect the threatened species.
Under the guidance of Dr. Mahmood Shivji, the Guy Harvey Research Institute has been at the forefront of shark conservation efforts for years. Of particular interest to the scientists at the GHRI is the plight of the tiger shark, the large migratory shark with a fierce reputation that is engaged in an even more fierce battle for survival. Tiger sharks are heavily overfished, due in large part to the species being an unwilling partner in the international shark fin trade, a diabolical business venture that is responsible for the deaths of tens of millions of sharks each year (the fins are sold primarily in Asian markets for use in shark fin soup).
Through the invitation of veterinarian Dr. Neil Burnie, who is independently starting a tiger shark research effort, the GHRI participated in a recent trip to Bermuda to continue their on-going research of tiger shark populations in the Caribbean and western Atlantic Ocean. I also tagged along, piggy-backing on a TV shoot for an upcoming episode of Sport Fishing Magazine TV (which is under the direction of Ken Kavanaugh, who produced most of my “Portraits from the Deep” episodes). As it turns out, Bermuda has become a sort of hot spot for tiger sharks. Neil has located a consistent source of tigers in an area known as Challenger Bank, just 17 miles south west of Bermuda. This spot is well known among anglers as yellowfin tuna and large blue marlin also frequent this underwater plateau.
Neil’s 34-foot Prowler, “Bones”, was an ideal working platform for both the scientists and film crew. Anchoring up on the bank, Neil and his assistant, Choy Aming, set out a strong chum line using tuna carcasses as bait. Wahoo, tuna, barracuda and marlin would visit us in the chum line, but we were here for Tigers – and Challenger Bank did not disappoint.
Although reluctant at first, the fragrance of the bloody chum line proved too strong for the tigers to resist. Once they drew nearer to the boat, our first order of business was to shoot the sharks – on film, of course. As they approached, several of us grabbed our gear and slipped over the side of the Bones and into the water to film the cautious movements of the suspicious tigers. We shot great video of the sharks for both entertainment and scientific study, but that was secondary to the main purpose of this expedition, which was to catch these animals with rod and reel so we could get them under control at the side of the boat in order to tag each shark with two different electronic devices. Sounds easy enough, right?
In order to do this, we needed an experienced and capable team. Joining Neil, Choy and myself was Dr. Brad Wetherbee of the GHRI, my children, Jessica and Alex, and several other crew mates and cameramen. Alex was brought along to be the muscle – it was his job to crank on the tiger sharks – while Neil, Brad and Jessica (who is an aspiring vet herself) would handle the tasks of getting the sharks in position alongside the Bones and then fitting them with tags.
Alex used heavy tackle to catch and reel in the tigers – a 20/0 circle hook with no barb attached to cable leader, with 130lb. Spectra line on a Shimano stand up outfit. Alex had his work cut out for him – on his very first catch an 800 lb. tiger shark peeled off a couple hundred yards of line. However, being an experienced angler, he got the shark to the boat within thirty minutes. When the shark was within reach, Neil and crew went into action, using an array of tail ropes and straps to secure the shark tight against the boat so it couldn’t thrash about and injure itself.
Next, Neil drilled four holes in the shark’s dorsal fin in order to attach a SPOT tag while Brad secured a PSAT. The SPOT tag was attached to the dorsal fin so whenever the fin broke the surface, the tag would connect with an Argos satellite and say, “I’m here!” The PSAT, on the other hand, collects environmental data such as water temperature, depth and luminescence every two minutes and provides a calculation of the shark’s geographic position (in short, this tag allows us to find out how the shark uses the water column and tells us where each shark goes). The SPOT tag is a permanent fixture on the shark and is good for only as long as the battery lasts while the PSAT is designed to disengage from the shark after six months and float to the surface to transmit a summary of the data to a satellite, which then relays the information to a lab at the GHRI.
This entire process took about twenty minutes to complete, at which point Choy, Neil and Jessica released the straps and tail rope, take out the hook, and allowed the shark to swim off. I was positioned in the water in order to observe the shark down to a depth of 80 feet and then let it swim away. However, the shark swam off too fast for me to follow for very long! I was amazed and impressed at the resilience of this great animal and how easily it recovered.
After the first tagging, we tagged three more large tiger sharks (all between ten and twelve feet long) over the course of several days. The expedition to Bermuda proved to be a very successful beginning to what will be a long-term collaborative research effort conducted by Neil Burnie’s group and the GHRI under the auspices of the Guy Harvey Ocean Foundation. The main goal of these expeditions is to learn more about the life history of these remarkable animals by studying them at different sites in the western Atlantic. Eventually, we will collect enough data to allow us to build a profile of the tiger shark populations in this region, which in turn will give us the data we need to create meaningful and viable measures for protecting these endangered tiger sharks.
For more photos from the expediton to Bermuda, visit the Guy Harvey fan page on Facebook at http://www.facebook.com/home.php?#/pages/Guy-Harvey/120398390965?ref=ts.
UPDATE: Since our return from the expedition to Bermuda, we have received lots of data from the tags. Perhaps the most useful information we have seen so far is the geographical charting of the shark’s locations – many of the tagged sharks rapidly dispersed from the Challenge Bank area soon after being tagged, covering hundreds of miles in the open ocean in a short time. This data suggests that protecting the tiger sharks from overfishing will require the management and enforcement of conservation efforts across large areas of ocean rather than in small, localized regions. Unfortunately, the movement of the sharks across such large areas also means they are susceptible to long line gear and can be caught and killed by commercial fishing activity until conservation measures are enacted (several tiger sharks I have filmed at Tiger Beach in the Bahamas have long line hooks in their mouths). We will keep you updated on the progress of each of these tiger sharks as we learn more about their biology and life history.