• Sharks I Have Known, Loved and Learned From

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    Recently, Luxx visited the Cape Cod Museum of Natural History in Brewster to listen to Greg Skomal, one of the world’s most informed shark specialists. We share our time with him.

     

    Greg Skomal loves sharks.

    He knows them intimately.

    He follows their patterns around Cape Cod and throughout the Atlantic.

    He knows them by the names he gives them.

    He believes fervently that sharks are widely misunderstood.

    In talking about his book, The Shark Handbook, Skomal explains:

    shark handbook

    “I want to give readers an idea of how we study them, shark diversity, their unique body structure, how they are used in fisheries and how we need to conserve them. I am trying to tell people that what you see on TV is not representative of what we know and what we understand about these unique animals. They are not killing machines that swim around making baby sharks and eating people, but they are unique, have a unique life history.”

    When Skomal was an undergraduate at the University of Rhode Island, his obsession was working with white sharks. Narragansett Federal Laboratory was not far from his campus. He began volunteering there and participated in his first shark tagging program.

    “Back then, we did not have laptop computers. Now, we actually can strap them on the sharks,” he explains with a degree of awe.

    In those early years as a shark enthusiast, most of Skomal’s research involved dead great whites. “We learned a great deal from the dead,” he explains. “We would cut themup and discover what the animals ate. We would take sections of back bones, and like a tree, determine the animal’s age by virtue of the rings on the spine. We would study their reproductive systems.”

    skomal 1Today, Skomal is at the cutting edge of a startling increase in the number of white sharks that are visiting the waters of Cape Cod, especially around Chatham. One reason for this upsurge is the proliferation of the grey seal population.

    We have opened up this incredible café and these customers are showing up to take advantage of this food resource,” Skomal explains. “It’s given us an ideal opportunity to go out and study this animal.”

    Skomal’s professional focus on sharks began in earnest in 1987 when he worked for the state of Massachusetts. In 1995, he reached into his savings account and traveled to the Neptune Islands in Australia to work with colleagues, diving for white sharks.

    That’s when he graduated from dissecting dead sharks to swimming with live ones.

    From then on, Skomal developed a phrase that captures his work: Sharks I Have Known, Loved and Learned From.

    “I was totally motivated to learn as much as I could about the white shark. What does it do from day to day, to minute to minute, second to second. Early on, however, we did not have much technology.”  He literally had to view the sharks to understand their patterns.

    In September 10 years ago, Skomal was working off Naushon Island when he encountered “Gretel.”

    “She was the most frustrating shark I ever have known,” he recalls. She was a 14-foot female who entered a salt pond and then could not find her way out. She spent two weeks trapped there.

    “I experienced some of my highest highs and lowest lows,” said Skomal. “She was trapped in very shallow waters, only three feet deep at the gap of the pond. It was like a cat stuck In a tree that cannot get down.

    “Her belly would constantly bump against the bottom of the pond and she would go back in. We eventually used a weir net and high pressure pumps to get her out”

    But before Gretel escaped, Skomal and his team placed a tag on her with new pop-uup technology to record temperatures and other data. “We were set up for three-dimensional analysis of where she would go for months. Unfortunately, we programmed the tag to pop up on April Fool’s Day. Bad choice.”

    Skomal’s team followed Gretel out into Vineyard Sound. “We are going to be the first team to use put this new technology to use. We envisioned ourselves on the cover of National Geographic.”

    Forty-five minutes later, the tag came off.

    Skomal’s fortunes have picked up considerably since then. He tagged 39 white sharks by last year.

    New acoustic tags, which emit very high-frequency pings, have proven revolutionary.  They can remain operative for up to 10 years.  There is a large acoustic receiver in the Orleans/South Chatham area that can pick up signals from the tagged sharks.

    They are individually coded to track specific sharks by date. “Now we can recreate their movements in our local waters – day or night, high tide or low,” he explains. One valuable result is getting a true sense if and when the animals swim near local surfing and swimming beaches.

    Julia can be traced in yellow dots. She really likes to roam between Chatham inlet to south Monomoy.  Marge likes to swim around Orleans.

    When Marge travels to Truro, Julia avoids her. That indicates sharks territoriality, Skomal explains.

    Scarface is a 12-foot female. Her $4,000 acoustic tag has led researchers to new understandings about just how far and wide these animals swim year-round. She has been detected across the East Coast, from Daytona Beach to Halifax in Canada.

    Currently, Skomal is monitoring sharks via 15 tags. Three others have failed.

    sharks i lovedFor a long time, Skomal and his fellow researchers thought that an individual shark followed a relatively simple migration path. One might go to the Gulf of Mexico stayed on the Atlantic shelf moving north to south. “We thought we had it all figured out,” he said.

    That changed with Curley, who was discovered nine miles east of Chatham feeding on a whale carcass. Despite the name, Curley is a 17.5-foot female.

    “We put a sophisticated tag on her and went online to follow Curley’s movement. She traveled to the edge of the Continental Shelf from November to early January then to the Sargasso Sea in the middle of the Atlantic Ocean and by spring to near George’s Bank.

    “When Curley was on the shelf, she stayed in relatively shallow water as cold as 48 degrees. But, then she would dive as deep as 2,500 feet every day. This was remarkable, unique behavior. Sometimes, Curley would experience temperature changes as dramatic as 80 degrees on the ocean surface to 30 degrees on a dive. Physiologically, how did she withstand those changes?”

    Skomal continues to raise funds for more research. Fifteen tagged sharks won’t come close to solving the mysterious nature of these animals.

    He has partnered with an nonprofit organization, Osearch, that specializes in capturing big fish.

     

    Ultrasound_PT2_1805Osearch owns a unique vessel ideally suited for capturing sharks. It can lift the animals onto a platform to give scientists live access. When captured, Skomal and his team have about 15 minutes to affix multiple tags, take some tissue and blood samples, perform an ultrasound to determine if the shark is pregnant and return it to the water safe and sound.

    Mary Lee was a 16-foot shark tagged on Osearch. Skomal followed her around the Continental Shelf into George’s Bank. She visited Florida in January, came back to visit relatives in Long Island, then returned to George’s Bank before heading to Bermuda and later into the Sargasso Sea.

    No one anticipated such a vast roaming area as well as the rapid movements. “We are just scratching the surface of our understanding,” says Skomal. One tagged shark, Lydia, has traveled more than 30,000 nautical miles in a single year.

    “Lydia has demonstrated movements much more dynamic and complex than ever anticipated,” he says.

    One question that dogs Skomal: Why do sharks dive as deep as 3,000 feet in the middle of the Atlantic Ocean? What are they doing down there?

    He hopes that new tags that have the capability of videotaping the sharks will offer some answers to this and other key questions.

    Skomal also sees drone-like, robotic underwater vehicles – the same ones used to search for the missing Malaysian aircraft – being used to research sharks.

    Two years ago, Skomal was able to follow a large 16-foot shark named Large Marge with a transponder strapped to her. She was tracked for hours off Orleans. She was the shark made famous by a photo of her swimming alongside a kayaker and surfer.

    How did Skomal know that was Large Marge? By her dorsal fin, which is similar to human’s fingerprint.

    Grey sealsSkomal theorizes that Cape Cod may be a mating areas for sharks. Certainly, the proliferation of grey seal populations is making this area very attractive to the hungry creatures.

    Skomal doubts that sharks will attack humans. “In all likelihood, no,” he stresses. “They are not dumb animals.”

    At the same time, he adds: “They do make mistakes.”

    The important thing is to use common sense, he says. Don’t swim out 200 meters and splash around near grey seals. Don’t go out far alone at dawn or dusk either.

    Skomal notes that currents and tides around the eastern shore of Cape Cod where seals congregate are more dangerous than a shark.

    “Look at the statistics,” he explains. “If you are afraid of dying, don’t get in your car. Driving to the beach is more likely to kill you than getting into the water and confronting a shark.”

     

    June 24, 2014