If you like mysteries, Thursday’s Shark Week lineup is for you.
In Jungle Shark (10 p.m.), Dr. Craig O’Connell, the man behind the Sharksafe barrier seen in this year’s Sharks Among Us special, travels to Costa Rica to find out how young bull sharks, which swim up a freshwater river to avoid being prey for larger bulls, coexist with the large crocodiles that call the river home. Why? That knowledge, combined with O’Connell’s background in chemical repellents, might one day lead to a new way for humans to avoid run-ins with bull sharks.
“We initially went to Costa Rica before the actual filming, and one of the things I noticed was that the water was so incredibly murky that there is no way that these sharks are going to be able to see the crocodiles. They have to be able to detect them some other way,” O’Connell tells Yahoo TV. “I went back home, did some reading and learned that crocodiles like to communicate using pheromones. That was my next step: I had to create my scientific hypothesis, and it was that these bull sharks have the ability to detect these pheromones, and they can use them to identify that there’s crocs in the area, and they can flee, so that they don’t get eaten.”
As you can see in the sneak peek above, O’Connell and cinematographer Andy Casagrande place a sonar cam in the murky water at night, and watch as a juvenile bull shark accelerates past a croc. “I think that was one of the best moments of the entire film shoot, because witnessing some sort of interaction between a crocodile and a bull shark is exceedingly rare,” says O’Connell,
Other memorable moments in the special include the team dragging a shark decoy in the water to confirm that a croc will attack. One does, and it takes them more than three hours to get the $10,000 decoy back. O’Connell says: “I’m so used to working with sharks, and sharks immediately realize a decoy is not a real prey item, and they release it, and so it takes a total of one minute to bring it back. But I forgot to account for the typical behavior of a crocodile, which is they bite their prey, and they often keep it in their jaws and swim down to the riverbed and bury their prey underneath a log and save it for later. It was three hours of torture, pretty much.”
With the help of local croc experts, they also extract a pheromone sample from a croc so O’Connell can use the scent in experiments to see if it is, in fact, what’s repelling the sharks (“I never thought I would be wrestling a crocodile for a Shark Week film,” Casagrande says). With promising preliminary results on bull sharks in the special, the door is open for a lot more research, O’Connell says. He’ll have someone continue to run trials for him on more bull sharks and tiger sharks. He says: “I would hypothesize that the bull sharks recognize this as some sort of alarm signal and stay away, but are these crocodiles a threat to tiger sharks, and do they ever encounter one another in the wild? I’m not necessarily certain. I don’t know if it’s going to work on any other species. We’ll have to see.”
Thursday’s other new special, Nuclear Sharks (9 p.m.), asks another question: How did reef sharks, who are thought to be nonmigratory, end up repopulating the waters of Bikini Atoll, a marine ecosystem in the Marshall Islands decimated by 20 years of Cold War nuclear testing? For the answer, Philippe Cousteau, grandson of legendary oceanographer Jacques Cousteau, his wife, Ashlan Gorse Cousteau, and marine biologist Luke Tipple head to Bikini to tag sharks and track their movement in the central Pacific.
They make multiple memorable dives in the film, including one to a sunken aircraft carrier (“It’s like you’re actually walking on her deck, like you’re going through the galley,” Ashlan Cousteau says), and the one in the clip above, with sharks swirling all around them. “You’re in the shadow of these nuclear blasts, the worst fire and brimstone that humanity can engineer, and yet, we couldn’t stop nature. Nature found a way to recover, to rebound and to thrive,” Philippe Cousteau says.
While their tags reveal how far reef sharks are willing to travel, the team’s most important discovery is that 50 percent of the sharks they tagged ended up illegally fished — despite the Marshall Islands being home to the world’s largest shark sanctuary. “One of the big solutions that people have been promoting on the international conservation issue front, myself included, has been developing marine protected areas,” Philippe Cousteau says. “Unfortunately, in a lot of these very remote places — out in the Pacific Ocean, in the Atlantic, the Indian, wherever it may be — establishing these marine reserves is the first step. Actually enforcing them is the next step. Kudos to the Marshall Islands: in 2011, they established a marine reserve three times as large as California, which is really incredible. But they’re a small island nation, and they need help. Large NGOs [non-governmental organizations] come in to big fanfare, establish these big reserves and then they leave. It’s not enough. Clearly, the enforcement of these reserves is paramount, if they’re going to be effective. I think we provide evidence through this expedition that it’s a big crisis.”
What’s the next step? “We are talking with folks at the State Department about what we learned,” Philippe Cousteau says. “We’re doing lots of different things with the film and with the information coming out of this to help to promote the idea of following through with these big, big global NGOs. I think they’ve been a little too quick to pat themselves on the back and say, ‘Hey, mission accomplished when we established these reserves.’ I think [the film’s] going to upset a few people. I think there are some people that don’t want us to talk about this.”
Technology may be the key. “There are some really interesting tagging technologies, GPS-tracking technologies, drone technologies, satellites,” Philippe Cousteau says. “There’s a lot of things that are available out there, that we can leverage. It’s just making that part of the plan of establishing and enforcing these marine parks.”
Adds Ashlan Cousteau: “If we can find ways to put new technology or unmanned drones out there to try to police these areas, that’s going to take manpower, that’s going to take money, but it’s definitely a lot less than big ships that are fully manned.”
In the meantime, the couple can celebrate one fact: The shark that Ashlan Cousteau tags in the film was not one that was fished. “I probably would have traveled to Guam myself to meet the people that would have taken her,” she says. “I do not have children yet. [Tagging that shark] was the hardest thing that I have physically ever done in my entire life. You have to remember that sharks not only are moving constantly, but they can move on a dime. They can go up and down the water column, obviously. Their skin is incredibly hard to pierce. When I finally made that shot, I was so excited, and then I immediately was worried about the shark, because I wanted to make sure that I didn’t hurt her. I didn’t. She came back to check us out probably like five minutes later. I’m so proud, because she was one of the sharks that actually traveled to three different atolls. To be able to, as a journalist, as a citizen scientist, be a part of actually gathering data with these sharks, it was truly remarkable.”
Nuclear Sharks airs June 30 at 9 p.m., followed by Jungle Shark at 10 p.m., on Discovery.