For scientist Neil Hammerschlag, it was just
another Sunday. He was out cruising the reefs near the Florida Keys, hunting
for sharks — not as trophies, but for research aimed at keeping them out of
display cases and in the water. In many places, these iconic predators are
disappearing.
A research assistant professor at the University
of Miami, and the director of its R. J. Dunlap Marine Conservation Program,
Hammerschlag spends every other weekend in southern Florida dragging baited,
shark-safe lines behind a boat, hoping one of his research subjects will take a
bite.
When he and his team catch one, they outfit the
shark with either a satellite tag or an ID tag, take tiny
samples of muscle and fin and a vial's worth of blood (they check to see if the
shark is pregnant), then send the shark on its way. The whole process
takes about five minutes.
Big catch
On Sunday, May 27, they were having plenty of
luck. Something snagged the other end of the 75-foot (23-meter) line, and
Hammerschlag began to pull it in. Right away, he said, he could tell something
was different.
"It's a lot of work to bring up a line, but
I can usually do it myself," he says. This time, he needed help.
He and a colleague joined forces. "We
didn't know if we were pulling up a sunken boat, a monster shark, a school bus
— we had no idea which it was," Hammerschlag told OurAmazingPlanet.
They were in about 150 feet (46 m) of water,
and, even as the two men strained to pull in whatever it was, it remained
invisible, hidden by the murk of the shallow ocean.
"As soon as it came to the surface, it
literally took my breath away, it was so big," Hammerschlag said. They had
hooked a massive bull shark, the region's top predator; the shark was about 10
feet (3 m) long and, the researchers estimated, over 1,000 pounds (454
kilograms).
"It's one of the biggest bull sharks I've
ever caught, and it's the biggest bull shark I've ever tagged,"
Hammerschlag said — and he's tagged more than 1,000 sharks. "When this guy
rocked up, it just took my breath away."
Iconic
predators
It turned out it was, in fact, a
lady. Like many other shark species, female bull sharks are larger than males.
But bull sharks of either sex are nothing to be trifled with. Like great white
sharks and tiger
sharks, bull sharks have serrated teeth — an accessory that allows them to rip
and tear apart their meals, which means they can go after far bigger prey than
smaller shark species can.
Bull sharks "have the most
testosterone of any animal on the planet, so that should tell you a little
something," Hammerschlag said. They also like to hang out in shallow,
coastal waters.
Despite what this implies for our own species,
Hammerschlag said the sharks don't specifically target people. "They
possess the machinery but lack the motivation," he said.
Bull sharks are one of the three species most
often blamed for unprovoked, deadly shark
attacks around the world, according to the National Oceanic and
Atmospheric Administration.
Big threats
Yet far more commonly, people attack sharks.
Their fins, prized for shark-fin soup,
a traditional Chinese dish, fetch high prices. According to numbers cited by the
Humane Society, as many as 73 million sharks are killed for their fins each
year.
Overall, many shark species
are facing steep declines. Figuring out what is driving that trend,
and reversing it, is a big motivation of Hammerschlag's research. "We know
a lot of shark populations are in trouble, but the question is, what is
happening to Florida Keys sharks?" he said. "And if you want to be
effective at conserving them, what would it take?"
Because they had run out of
satellite tags — they're expensive — after taking biological samples,
Hammerschlag attached a simple ID tag to the bull shark. They'd have no way of
tracking the giant female. With a push, Hammerschlag sent the shark on her way.
He said the experience wasn't scary.
"This is a predator like none other in the
world, and it deserves complete respect and attention," he said. "If
your heart doesn't skip a beat, you don't have enough respect for it."
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