URI researcher helps keep an eye on traveling sharks
It’s mid-summer, people are flocking to the beaches and just about everywhere—even on television—there appears to be a fascination with sharks.
But for Brad Wetherbee, a biology lecturer in the College of the Environment and Life Sciences, the fascination with sharks is not just a seasonal thing. He has been interested in the creatures for years, actively trying to solve some of the mysteries surrounding the swift predators that have long been feared by swimmers and embraced by filmmakers.
During the school semesters, Wetherbee teaches biology and marine biology to hundreds of undergrads. But during the summer and sometimes during semester breaks he is employed by a research institute which needs him to help them track the sharks and other mysterious denizens of the deep.
It all started at the University of Hawaii where he earned his doctorate. The university had a program tracking sharks with acoustic transmitters. The devices had severe limitations in that the researchers had to stay close to the sharks because the range and reliability of the transmitters left a lot to be desired.
In the late 1990s, however, new tracking devices that could communicate with satellites were developed and so wholesale tracking programs were possible on a host of marine creatures such as blue fin tuna. There evolved two basic devices—those that could communicate when the creatures came to the surface and those that would automatically pop up to the surface in the case of marine life that rarely surfaces.
One the signals are transmitted to satellites, triangulation determines the creature’s exact coordinates.
It’s a system that is better than the acoustic devices of years ago but it is not without practical problems, especially when it comes to sharks which are always on the move.
“If we try to get the devices on the fish for a long time, we bolt them on and then you are lucky if they stay on as long as the batteries last,” says Wetherbee. “So many things can go wrong. It’s a big battle.” A sole AA battery powers the devices.
But the battle is worth the challenge because the researchers are finding some surprising things about certain species of sharks (there are 500 of them), says Wetherbee.
He and other researchers are fascinated with the travels of tiger sharks. It was once thought that the sharks were coastal dwellers but the tracking studies show they swim thousands of miles out into the Atlantic for half the year before returning to warmer climes in the Bahamas, for example.
“It’s surprising how much time tiger sharks spend in the open ocean,” says Wetherbee. “We now know where they go but we don’t know why. Tiger sharks are hard to figure out. They don’t like to conform.”
The lack of conformity is also surprising. “Half the year they are coral reef fish and the other half is spent in the open ocean. That’s like some animal that spends a half year in a rain forest and the other half in a desert.”
Wetherbee does the tracking for the Guy Harvey Research Institute in Florida. Guy Harvey is an entrepreneur who has a doctorate in marine biology and offers a whole line of marine products from T-shirts and swim wear to even original paintings. “He’s a conservationist who sells things to support his research institute,” says Wetherbee who has been with Guy Harvey for 13 years. “He’s keen on giving something back” says Wetherbee of Harvey.
The institute has a unique website http://www.nova.edu/ocean/ghri/index.html where visitors can log on to watch various named sharks and the routes they have travelled over the last few years.
Right now, says Wetherbee, the institute is tracking 16 sharks and the data comes in constantly. Wetherbee has students, some paid and some just getting credit, to help him log the data. “It’s good all around as it helps me get away from some tedious work and gives them some experience doing research. Of course they are not out there tagging sharks which they would love to do.” Wetherbee has taken some students with him to tag sharks on occasion—even his young daughter.
All of the expenses in the tracking operation are paid by Guy Harvey. The tracking devices themselves cost $5,000 for the pop-up types and $2,000 for those bolted onto a shark’s dorsal fin. On top of that are expenses for crews, boats and satellite usage fees—that’s a lot of T-shirt sales.
Tracking sharks and other marine life is essential to understanding the populations, says Wetherbee. So much is unknown about life in the oceans. “Our government is committed to protecting fish populations. Our whole goal is to manage fish populations in a sustainable way and information gathering is all important.”