A protected species in the Bahamas, whitetips are hunted elsewhere for their fins
Demian Chapman has one of those jobs that turns heads at social gatherings: he’s a shark biologist. The New Zealand native, who is also an assistant professor in the School of Marine and Atmospheric Sciences at Stony Brook University, is in the middle of studying the oceanic whitetip sharks.
Known for living far from land, the whitetips, which eat tuna, mahi mahi, marlin and squid, have declined precipitously in numbers in the last few decades, in part because some people consider their fins a delicacy.
Chapman, his wife Debra Abercrombie — also a shark biologist — and several other researchers recently published results of a study on the whitetips. Starting in 2011, Abercrombie and other field biologists went to the Bahamas, where the waters are aggressively patrolled and the sharks are actively protected, to fit some sharks with pop-up satellite tags that could track their location.
As Chapman explained it, the researchers put bait in the water near the Bahamas at a time when the sharks are closer to land. If it’s alone, the first shark won’t typically approach a piece of bait. Once other sharks arrive for a meal, however, the shark’s competitive instincts take over and it becomes easier — albeit still a struggle — to reel them in.
The researchers slip a rope around the tail of the shark and then drive the boat slowly while they outfit the cartilaginous fish with a tag. Chapman said the tags, which weigh only a few grams, are probably barely noticeable to the sharks, which can be as long as eight feet and can weigh about 150 pounds.
What the tags showed was that one of the sharks traveled about 2,000 kilometers, or over 1,200 miles, in under a year. Five of the sharks traveled outside the exclusive economic zone (or EEZ) for the Bahamas, where they are better protected. This suggests that more countries might need to safeguard these sharks.
This March, the Convention on International Trade in Endangered Species of Wild Fauna and Flora is meeting in Bangkok, where representatives from several countries will consider whether to list this species. Such a listing would mean that permits would be required to trade the species across international boundaries. People caught trading the species without those permits would face penalties.
The sharks “do spend a lot of time in the Bahamas, where they are well protected,” Chapman said. “The fact that they do leave raises concerns. If you don’t have some parallel measures outside the Bahamas, that may undermine what the Bahamas has done.”
Chapman hopes that this paper, along with further research, helps to raise awareness of the delicate state of the shark population.
Countries vote to determine which species make it to different protected lists. A species has to get two-thirds of the vote.
“It’s difficult to get,” Chapman said. “Some countries that are pro-shark trade — if they consume fins — will never vote for a shark to be” on the list.
There’s definitely politicking at these meetings, he said, where some countries vote to list species in exchange for the votes of other countries on other organisms.
Chapman went to Asia in late February to help train customs agents to recognize the fins of different sharks.
Unusual for his combined expertise in DNA analysis and field work, Chapman made a remarkable find in 2005. A female hammerhead shark had been in an aquarium without any access to males for about three years. After all that time in isolation, it gave birth. The aquarium sent a copy of the mother and pup’s DNA to Chapman. He concluded that the shark had given a so-called virgin birth.
While impossible in mammals, animals like sharks, snakes and turkeys can somehow combine an unfertilized egg with the genetic code of a polar body, which essentially acts like a sperm.
The polar bodies are “cells that could have been an egg” but were produced during the production of eggs, he said.
Residents of Miller Place, where they recently purchased a house, Chapman and Abercrombie, who is originally from South Carolina and is a consultant for the New York Department of Environmental Conservation, met when they were at a field station in the Bahamas.
Chapman tries to avoid the “Shark Week” series on the Discovery Channel because of the frequent recreations of shark attacks.
“They try to add a conservation message,” Chapman said, “but it’s difficult to reconcile how the sharks need to be protected” after people have watched them attack swimmers.
As for working with sharks, he said he’s never had a “bad experience with them.”