Editor’s note: Steve Kessel, Ph.D., is Shedd’s director of marine research. He shares his most recent experiences in his ongoing shark research project in the Bahamas.
The weather is beautiful, and the water is calm: perfect conditions for studying sharks.
We are putting around in a research skiff in a channel between the deep ocean and the shallow flats of the Great Bahama Bank. Around us are the islands of the Exuma Cays, fringed in white sand, which many find to be the most beautiful in the Bahamas, or even the world.
We’ve been scouting the location for about 15 minutes, looking for the most suitable area to set the first scientific longline for our April shark research expedition. Conducted with permits from the Bahamian government, this brief catch-and-release process lets us gather invaluable data about these thriving shark populations.
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I instruct the five-person crew on the protocol for setting the line. We must work as a team to ensure everything goes well and safely, but two crew members have never assisted me with this research before, so I assure them we are going to take things nice and easy. We are setting the line with only five hooks so that we can take our time processing any encountered sharks while bringing the new people up to speed.
By the time we are halfway through our set, everything is going
smoothly. The line is spooling out the back of the skiff, the hooks are
being baited with fish, and the gangions (branches off the mainline that
contain the hook and bait) are seamlessly being clipped on. Seconds
after clipping on the fourth gangion, though, there is a sudden jerk and
the mainline starts to tear off the spool. We haven’t even finished
setting the line and we already have a study subject!
We race to get the rest of the line set so that we can process the shark. By the time we finish setting the line, though, we are all startled by a loud crash from out of nowhere: thunder! It’s the rainy season in the Bahamas, and isolated storms are unpredictable. I turn around to see a huge squall approaching, with clouds black as night. This is going to be a violent one.
Shedd’s spotlight on sharks
I have been working for the Shedd Aquarium for a year. During my
research career, I have primarily concentrated on elasmobranchs (sharks,
skates and rays), and as Shedd’s director of marine research, I oversee
all our research programs that are focused on economically important
species in the Bahamas and Caribbean region. Sharks are one such group
of animals that contribute considerably to the Bahamas’ economy through
shark-dive tourism, and my own research investigates shark and ray
populations within this region.
Whenever I tell people I work with sharks, their first response is almost always, “Why do you live in Chicago?” I am often surprised at how few people are aware that Shedd has two facilities: the aquarium, on the shore of Lake Michigan, and our 80-foot research vessel, the R/V Coral Reef II, based in Miami.
It is a rare and fantastic resource for any organization, whether academic or purely research-focused, to have access to such a large, functional vessel as we do at Shedd. It was this resource, in fact, that was the biggest lure for me coming to work here. I knew that with access to this vessel, we could make a real difference for conservation research in the Bahamas, including a focus on sharks and rays.
Globally, many shark and ray populations are experiencing declines, which are primarily driven by overfishing. Sharks originated around 450 million years ago and have survived five mass extinction events. Not until the age of humans have shark populations ever been at the levels of risk we see today, with around one-quarter of all elasmobranch species currently threatened with extinction. To reduce and even reverse these declines, we need good data generated by applied research to inform conservation and management initiatives.
“I knew that with access to this vessel, we could make a real difference for conservation research in the Bahamas, including a focus on sharks and rays.”Steven Kessel, Ph.D., director of marine research
Working against the weather
Back in the Bahamas, we race back to the boat to switch the gear, and the captain informs me that, based on the radar, this squall is about 10 miles wide. We can’t wait it out. We need to get the shark off the line and the line out of the water.
We head back at full speed and grab the marker float just in time for the storm to hit. The change in conditions is instantaneous. Pounding rain and screaming winds are on us in a second. Despite the sheltered nature of our location, the waves build instantly. Driving the skiff forward to allow the line to be pulled in takes enormous concentration and coordination. The conditions require us all to yell at the top of our voices to communicate. We make steady progress until we reach the shark.
It’s a beautiful Carcharhinus perezii—Caribbean reef shark—and the main target species for our current research. This would be a perfect specimen to add to our study, but as much as it pains me to do it, for the safety of the crew and the shark, we have to let this one go.
I pop out the hook, the shark swims away, and we continue to fight the conditions hauling the line. Once the line is up, it’s too rough outside the shelter of the channel to return to the mother ship, so we flee to one of the adjacent beaches and huddle together for warmth for the next few hours while the storm passes. It is a real baptism by fire—or more accurately, by torrents of water—for the new team members. But much to my delight and relief, they take it all in stride.
Building our knowledge of wild sharks
Happily, on this research trip, we got all our bad luck over with that first day, and we spend the rest of our trip collecting valuable data on the region’s shark populations.
We use two main methods to assess shark and ray abundance in the Bahamas and Caribbean: shallow-water bottom-set longlines and baited remote underwater video (BRUV) surveys.
The scientific longlines are a safe and standard research technique for estimating the relative abundance and biodiversity of sharks and rays in shallow waters. They are set from a tender for an hour. Sharks encountered on the haul are brought alongside the tender, and we collect data including species, sex, total length and several other measurements.
Each shark receives a passive integrated transponder, or PIT tag—like microchipping your dog—and a U.S. National Marine Fisheries Service identification tag inserted at the base of the first dorsal fin. If we encounter these animals in subsequent years, we’ll be able to identify them quickly and safely, and add to our database on them. Finally, we take a tiny fin clip for genetic analysis and a blood sample.
Not all our data is collected in person. We are also conducting the BRUV surveys throughout the region as part of Shedd Aquarium’s partnership with Global FinPrint. By distributing underwater video cameras throughout the region—and later scoring the footage in partnership with Shedd’s Teen Learning Lab and volunteer program—we can build our understanding of shark abundance and biodiversity in key habitats throughout the region.
Strengthening shark sanctuaries
Our trip was a huge success, generating lots of important data to help us understand the diversity, demographics and distribution of shark species. These data support our long-term collaboration with the Bahamas National Trust and Department of Marine Resources to maintain and increase the effectiveness of shark and ray conservation and management measures in the Bahamas.
The Bahamas has some of the most progressive shark conservation and management policies in the Western Hemisphere, which has resulted in some of the richest shark populations in the western Atlantic and Caribbean region. In 1993, longlines and gillnets were banned from commercial use, greatly reducing the number of sharks caught and killed as bycatch.
In 2011, the Bahamas moved to designate the entire expanse of its 630,000 square kilometers (about 139,000 square miles) of national waters as a shark sanctuary, meaning it is now illegal to kill sharks anywhere in this protected area. This was the first and is still the largest shark sanctuary in the western Atlantic.
So if sharks are doing so well here, why do they need our help?
Progressive shark conservation measures like the Bahamas’ are rare around the globe, and when they result in abundant and diverse shark populations, like they have here, we have a responsibility to make sure they are sustained and remain protected. This is important not just for the Bahamas, but also for the surrounding waters of the U.S. east coast, the Gulf of Mexico and broader Caribbean region.
The sharks of the Bahamas can play a crucial role in sustaining shark populations in these other areas through spillover effects, and as long as these conservation and management measures are kept in place, the Bahamas can serve as a positive example to other island nations looking to improve their shark-related policies.
Shedd Aquarium’s research program aims to quantify and highlight the benefits of the shark sanctuary, not just in and for the Bahamas, but also the additional benefits it supplies to the surrounding region. These data will help to ensure the Bahamas’ progressive shark policies remain in place for years to come, safeguarding these rich and productive shark populations.
With the launch of Shedd’s new #KeepSharksSwimming campaign, we are stepping beyond a purely field-based research program for sharks and rays, and providing a platform for education and advocacy that reaches a wide audience around the globe through immersive underwater 360 videos with sharks.
You can visit Keep Sharks Swimming on our website to virtually come face to face with sharks in the Bahamas—and learn about the global plight of sharks, become more familiar with our dedicated research program and see how you too can take action to positively influence sharks.
The global threats to shark populations are far from over, but together we can keep the needle pointing in the right direction and help to safeguard shark populations long into the future.
Steve Kessel, Conservation Research team
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