Discovery Channel: Expedition Shark

Pizza Sharks

Richard has just arrived on board with a huge grin. “I got him!” he says. It’s a much different demeanor than yesterday, when he and Mike were incredibly frustrated at the “one that got away.” This time it’s not sharks but manta rays, though Richard says, “Rays are just sharks squished out and flattened like a pizza.”

One of the cool aspects of the Expedition Shark research is that they grab opportunities that arise to tag new species or ask new questions about the ones that they have been working with for years. When we drift fished to catch silvertips the thought was; why not try to catch them, too? They tried to catch the tiger shark when they spotted it, and they tried to catch grey reef sharks with a “claw.” Sometimes it works, and sometimes it doesn’t. After some frustration, Richard has now worked out a new technique to tag manta rays, and gather data on them as well as the whitetip and grey reef sharks.

“We are using technology straight out of a spy movie. We’re using radio tags and spy cams to look at what these animals are doing in real time,” says Richard.

Every morning since we arrived, divers have deployed a reefcam at Raging Horn, and retrieved it in the afternoon. The reefcam sits inside a watertight cylinder, and gives the scientists eyes into a world undersea. “Most of the shark research investigations put bait into the water. It’s based on observing the sharks after feeding them, which changes their behavior.” Collecting data on their movements and observing their real-time behavior undersea is shedding new insight into the world of these oceanic predators.

“Things we learned decades ago on land, we only have the foggiest idea about for the ocean, and about the largest predators on earth,” says Sanjayan. “It’s just astonishing. I’m a conservation biologist who has worked almost exclusively on land. And being part of this expedition really turned my worldview to understand that all the work that I do is really dwarfed by both the challenges of working in the ocean and the need for conserving the ocean.”

They set the reefcam at a “cleaning station,” where cleaner wrasse fish hang out and wait for marine organisms, including sharks, to show up for a parasite cleaning.  “Fish line up like a carwash,” says Dean Miller, who has worked with Richard on and off for the last eight years as Richard’s research assistant and videographer. “You see fish that would otherwise prey on each other, hold off. It’s like a no-go zone.”

Scientists have known that rays and sharks use cleaning stations for some time, but Richard wanted to find out how many different shark species are using them. Using a reefcam, they can find out. Cleaning stations are typically found where currents pass through, because the fish or sharks or rays can hover on the current while being cleaned. Sometimes the cleaning stations are near a geographically distinct feature. This particular cleaning station lies at 100 feet, across a channel where a strong current runs. Sea fans and soft corals abound here.

A spotted moray —much smaller and more colorful than the giant moray from the other day — makes its home in a crevice nearby. Near the cleaning station it looks like a giant graveyard of bones, broken off branches of once living coral, probably victims of a past coral bleaching event or perhaps a cyclone.

Coral bleaching happens when hot ocean temperatures cause algae that live in symbiosis with the corals to abandon ship. The coral polyps have a symbiotic relationship with zooxanthellae algae, and if the algae leave for too long, the corals die. When temperatures cool back down, the algae re-colonize and the reef can recover, but it takes time. Global warming has increased ocean temperatures around the world, and coral bleaching has affected many reefs worldwide, especially ones at shallower depths because shallow water heats up more quickly.

Dean gets the job of scanning eight or nine hours of reefcam video footage every night looking for interesting footage. “We didn’t know how many different species of sharks use the cleaning station,” he says. “On this trip we’ve seen manta rays, whitetips, silvertips, grey reef sharks, scalloped hammerhead, and a large unidentified species that was over 10 feet long.” He has also seen several interesting behaviors.

“We have seen stalling, which is when the shark uses the current to actually stop in the water to allow the cleaner wrasse to come up and service them. We’ve seen sharks moving out of the way for larger sharks of different and the same species. Yesterday I saw four scalloped hammerheads swimming side by side with the school of chevron barracuda.”

About halfway through our trip, Dean started seeing a lot of manta rays on the footage, and some of the divers spotted them when they’d put down and pick up the reef cam. So Richard thought, why not try to put pinger ID tags on them too? They hatched up a plan to use a speargun to shoot a pinger onto a manta’s wing.

So for the past three days, they have tried to do just that. The first day, Richard thought he had one in the bag. He shot the pinger from the speargun, but it whizzed past. “I’ve never had something where I was so sure I’ve had it, and then it got away.” He came back on board frustrated. Several other diver teams then tried, but didn’t see manta rays when they arrived at the cleaning station. But then, success! Richard, one; Mike, zero.

This morning, the crew tried to tag more mantas in teams of two, leaving every 15 minutes. Mike explains his shift. “We had all this crap with us—the reefcam, the data logger, the spear and cutters and zip strips, and down we go. We had a lot to do. Set the reefcam. Set the data logger. And we had to tag a manta ray in 20 minutes. That’s all the time you’ve got at that depth. So we got down there and I still had this crap in my hand and there was the manta ray,” Mike explains. “It was a beautiful situation where the manta was being cleaned. It was going in circles. He went around once and we couldn’t get him. He went in a second circle and pop, he’s done.”

The researchers have now completed a network of 32 receiving stations around Osprey Reef that detect the pingers. “Now we’ve got two manta rays in the grid,” Mike says, thrilled. Any time these mantas get within 300 feet of any of the receivers, their presence will get recorded. “This was an opportunity to put a really important tag on a very important species in very important experiment.” Richard, one; Mike, one; sharks and mantas, 62 tags.

Images: JR and Richard plan tagging strategy; Moray eel in the coral; Richard with spear gun for attaching pingers to manta rays.

Photos: Cat Gennaro/DCL

Silvertips, Tigers and Hammerheads, Oh My!

So there is Sanjayan, underwater, holding a whitetip shark on a rope; while JR has taken the other two to the boat. They’ve just finished the shark rodeo and we’re heading to the surface. Sanjayan holds a joint appointment as lead scientist for The Nature Conservancy and a research faculty member at the University of Montana. Coming into the show as a terrestrial ecologist, he presents fresh insight into what it’s like to experience some of these things for the first time.

“I’ve spent a lot of time around carnivores. I’ve been with polar bears and grizzlies and mountain lions and leopards and lions and wolves. I know how they behave and I know how to put myself in a situation where I’m never taking incompetent risks,” says Sanjayan. “But the moment I go in the water, I feel incompetent because I’m surrounded by animals that are more comfortable in their environment than me, and I can’t read them. Their body language is new to me.”

The sharks must be having a tough time reading us too. Seeing sharks dangling by their tails is a pretty funny sight. But all that lassoing gets the job done.

“When Richard first told me what he wanted to do, that he wanted to catch a shark by its tail, and transfer the lasso from your hand to its tail, I thought it was a crazy idea,” Mike said in a video diary he recorded for the show last night. “But that’s what we’ve been doing. And it works like a charm.”

The shark rodeo takes place at North Horn, at the relatively shallow depth of 55 feet. The plan had been to capture the same three whitetips that they’d placed the temperature loggers on, but catching the third whitetip they placed temp loggers on has proven a bit tricky. The outside capsule fell off her tail fin, so she’s not quite as easy to identify, but Richard can tell her by the fresh sutures on her belly.

After bringing the sharks they captured to the boat, Richard carries them one at a time to the kiddie pool to wait while they work on the third. Richard gives the new whitetip a pinger ID, and removes the temp loggers from the other two.

We watch the shark rodeo again the following day, catching one new whitetip, but the one they really want eludes us yet again. She’s turning out to be a slippery shark. So Richard tries a new capture technique for grey reef sharks. He opens the bait box, which gets them hyped. With fish in the water, the greys started circling and grabbing aggressively at the fish —very different behavior from their regular cruising mode. Once the greys get in a frenzy, Richard tries to hook their tails with a “claw” he invented —a metal hook that works like a handcuff.

We watch for another 20 minutes or so, but it’s not working so Richard makes the call to head up. “The claw just seems to not work around their tail. It just slips out,” Richard says. But the good news: “We’ve now tagged 50 sharks at Osprey Reef.”

Out here on the Undersea Explorer, there are two simultaneous agendas—conduct scientific research and film a documentary. Some days they do both at the same time. Other days, no cameras are around and they just capture sharks. Sometimes they film scenes on board the boat or in the water while no research is happening. Sometimes they just play around, like when Sanjayan, Richard and Mike lay in the kiddie pool with a small whitetip shark.

Sometimes different things are happening at the same time. Various divers are setting and retrieving receivers, fishing for sharks or setting out reef cams. When Undersea Explorer biologist Gabriel Vianna was retrieving one of the receivers at North Horn, several silvertip reef sharks “buzzed” him. Instead of keeping at a distance, the silvertips were checking him out, just slightly more aggressive than their normal cruising mode.

Since the silvertips were in the area, why not try to catch some? Silvertips forage differently than grey reef sharks, so researchers have to capture them differently too. While you can catch grey reef sharks by fishing off the back of a moored boat, silvertips tend to swim in deeper water and go after moving bait.  So with engines idling and winds behind us, the crew cast a 400-pound fishing line with bait, and let the line drift with the boat away from the reef. When the boat gets too far out, skipper Sean would reposition the boat closer to the reef, and then let it drift some more.

I watched the fishing from the back deck and saw several silvertips swimming in the water just off the duckboard. Despite heavy winds during our trip reducing water visibility, the ocean is still incredibly clear blue, and sharks can be seen with clarity under the water’s surface. After an hour and a half, several to try to take the bait, but not aggressively. Once again the sharks just weren’t biting.

Yesterday morning we were traveling from Admiralty Anchor to North Horn to try our hand at shark rodeo again. I was standing at the duckboard when crew started running past and talking about a tiger shark. Mike spotted something at the front of the boat and so we all went out there to check it out. It comes really close to the surface and Richard makes the call, “definitely a tiger.” I can see the tiger-like marking on its flanks. “It’s a small one.” It is probably about 10 to 12 feet long—larger than any of the other sharks we’ve seen so far, but small for a tiger.

“Ask me how many tigers I’ve seen out here at Osprey, including that one,” Richard says to Sanjayan. “How many have you seen?” Sanjayan asks.

“One,” Richard replies.

JR grabs some fish bait to see if they can hook it, so they can see whether it’s one they tagged at Raine Island earlier in the year, also part of the Expedition Shark film. Tiger sharks lurk in great numbers off of Raine, a green sea turtle nesting beach. The crew got in the water to film, tag and release them. Is it possible that one of those tiger sharks made its way out here, over 100 miles away? No one knows.

They try to hook the tiger shark for about 20 minutes but unfortunately, it didn’t take the bait. She swam close to the surface a few times, dove deep, surfaced again and then swam away— a typical day of shark research.

“First a thresher and now a tiger shark. What’s next?” I say. What a rare, privileged sighting! “Maybe a hammerhead? We’re going to see a hammerhead!” I say. I’m half joking, because that would be extraordinary and unusual to say the least to see all three of these species here within a few days.

But I’ll be darned if we don’t see just that — a great hammerhead — the very same afternoon. Topside cameraman Athol Foster was snorkeling off the reef at North Horn when he saw a hammerhead swimming below him. “It came up within couple meters of the surface and it circled around. It showed a lot of interest in me.” he says. “Had I been on my own and had no researchers telling me about sharks for the last several days, I probably would have been scared. I was sort of caught between both worlds, where you think, shoot, it could be really scary but I wished it would come closer.”

Soundman Cam McGrath was the only one already in Scuba gear, so he jumped in with a underwater camera and got about 20 to 30 seconds of good footage. As more people got in the water, the hammerhead seemed to get a lot more agitated. They kept most people out of the water so they could get some footage and by the time I was able to jump in with my snorkel and mask, it was gone.  Athol said it left by heading from the deeper water into the shallower Osprey reef shelf. But what an amazing stroke of luck we’ve had!

Images: Richard and grey reef; Pinger ID tag; Bait box frenzy; Sanjayan, Richard and Mike in kiddie pool with whitetip shark.

Photos: Cat Gennaro/DCL/Courtesy Wendee Holtcamp

Shark Surgery

After hours of waiting, waiting, waiting things can happen fast around here. One minute Sanjayan’s playing in the kiddie pool, cracking jokes. Fifteen minutes later, he’s got a whitetip reef shark by its pectoral fins, pinned on its back on the duckboard with two whitetips are lounging in the pool. They’ve never used the kiddie pool as a holding tank for sharks before, but it works brilliantly.

Richard, Mike and Dean dove down below with a box full of fish, which attracts the sharks. Sometimes up to 40 sharks will swim in a flurry around the bait box, and then it’s time for shark rodeo! Richard goes in with a rope and lassoes the tail. If I’m lucky, I’ll get to go down with the crew while they lasso sharks in the next few days.

Richard is something of a shark superstar around Australia. He’s been in four documentaries and worked on 20, and he has a sixth sense about sharks. I’ve seen him stick his head right in the water with two or three grey reef sharks circling near. I know I wouldn’t be that bold. 

“I’ve worked with sharks every day for 6 years at the Manly Aquarium (in Sydney, Australia),” he says. “So, I know when to stop. I know when they’re about to get crazy or dangerous.”

But today, I’m staying topside, and about to take on my new role as “shark nurse,” handing Richard surgical equipment.  Richard will be testing a new hypothesis about whitetip diving behavior and we’ll even be able to look at that data before the end of the trip, after they catch these same three sharks again and retrieve the devices.

“We think they’re using their diving behavior to thermoregulate,” explains Richard. Data they’ve collected on Osprey Reef whitetips over the past two to three years shows that during the night-time, they spend most of their time at shallower depths, but then do quick swims down deep. On top of that, as the night goes on, the sharks start going deeper and deeper.

Richard’s hypothesis is that the body temperatures of these “cold-blooded” animals start to heat up as the night progresses because they’re feeding constantly, and then they cool off by diving to the cooler, deeper waters below. “We have to prove that there’s a temperature differential between inside the shark and outside.” That will suggest that the deep dives can indeed cool them down. They’ll do a rough test by comparing internal body temperature to external temperature on these three sharks. We’ll find out in a few days.

Three divers arrive back at the boat with three lassoed sharks and hand the ropes to Sanjayan.  Scuba gear comes off, then Richard and Mike pull one shark at a time out of the water. Richard grabs the 5-foot-long shark, which wriggles at first, then calms down as he carries it nonchalantly up the stairs into the kiddie pool. They repeat this for the next shark, but the third shark they place upside down onto a mattress – the “surgery table.” The mattress has an orange-sized rip in it where another whitetip had taken a bite. “They’ve got a mouth full of tiny razor blades,” says Richard. I ask if he’s ever been bitten by a whitetip, and he shows me several tiny bite mark scars on his leg.

I sit near the shark’s tail, which Mike holds in place. Sanjayan holds down the shark’s pectoral fins which is hard work. JR places a hose so that saltwater runs constantly through the shark’s mouth and hence over its gills. Since sharks are fish, they breathe by getting oxygen through water pumping past their gills.

The first order of business is to find out whether the team has captured this shark before. If so, it will already have a PIT —or passive integrated transponder—ID tag inserted by needle beneath the dorsal fin. Before he even swipes the PIT tag reader, Richard says “We’ve caught her before.” He can tell some sharks apart by their spots! Sure enough, after swiping the PIT tag reader, he confirms she’s “Twin Peaks” — so named after two spots on her flank. “Twin Peaks” has probably told us more about whitetips than any other shark. And with this new data, she’ll show us even more.

Richard squirts the shark’s abdomen with antiseptic. I hand him the scalpel and he cuts an inch-long incision through skin and top muscle layer.

“Females have tougher skin than males because it protects them during mating,” Richard explains. “They can get a bit rough.” They can also tell she’s a “girl” because she doesn’t have claspers, two sausage-like projections.

During the incision she flinches a couple of times and Sanjayan yells, “Watch out!” since he can feel her squirm before the rest. They quickly pin her back down, making sure no one has any fingers close by those razor-sharp teeth.

After Richard completes the incision, I hand him a 2 ½ inch long black capsule — a “pinger” which gives the shark a unique ID. Unlike the PIT tag ID, which they can only scan when they capture the shark, the pinger ID gets recorded any time it swims within 900 feet of one of 29 receiving stations (aka data loggers) the researchers have set up around Osprey Reef. They will be installing three more on this trip and I will dive underwater tomorrow to watch one being set up.

Data collected from these pingers will give a great geographical perspective on where the sharks spend their time on the reef. Combined with the time-depth-recorder, which gives a vertical perspective of how deep they dive, they’ll end up with an amazing three-dimensional view of how sharks use their habitat.

I hand Richard the internal temperature recorder, a 1-inch long white capsule. Next, a needle threaded with catgut with which he expertly sews up the incision, twisting it in place with clamps and cutting with scissors.

The next order of business is to attach another temperature capsule to the caudal peduncle — the base of the tail fin — with a cable tie. Last, he takes measurements of the shark’s total body length from head to tail. Then she’s ready to go back in the water.

After we finish all three whitetips, they switch to a new project— luring in grey reef sharks by pitching in fish and a tuna head on a rope just off the duckboard. If we can lure them in, we’ll also implant pingers and collect data on these guys. Mike shakes a coconut rattle —used for millennia by ancient cultures — to attract them. Within minutes, I see one in the water just off the boat. They’re about twice the bulk and size of the whitetips. Magnificent!

Images: Sanjayan holds whitetip for tag retrieval; Richard and Mike with lassoed whitetip; Wendee (bottom right) with team performing "surgery;" Richard sews up incision.

Photos: Cat Gennaro/DCL