Researchers Tag First-Ever Free-Swimming Leatherback Turtles in New England
By Beth Potier, Media Relations
August 6, 2008
"Henry," the first free-swimming leatherback captured in New England waters, was tagged with a GPS-linked satellite tag by researchers from UNH's Large Pelagics Research Center. Photo: Connie Merigo, New England Aquarium.
UNH researchers have tagged one male and two female leatherback turtles off
Cape Cod. They are the first free-swimming leatherbacks ever tagged in New
England.
The 700 – 800-pound leatherback turtles, an endangered species, were
tagged July 17, 26 and 29 with GPS-linked satellite tags that transmit nearly
real-time tracking data, allowing scientists to better understand these elusive,
highly migratory giants to enhance their survivability.
“We investigators spent 20 years attempting to learn about these animals
on the high seas and temperate ocean waters, with only slow progress,” says
research associate professor Molly Lutcavage, director of UNH’s Large
Pelagics Research Center. “This work will be useful for marine resource
managers and others who want to understand how leatherbacks spend their days
in the New England region and beyond.” Lutcavage notes that this year’s
success is due to a convergence of people, know-how, and funding that allows
researchers access to resources like spotter planes and commercial fishermen.
And, says Kara Dodge, the Ph.D. student leading the tagging effort, the turtles
are cooperating. “It’s leatherback craziness this year,” she
says, noting that warmer water temperatures have brought an abundance of jellyfish,
the primary food source for leatherbacks.
The $5,000 GPS-linked satellite tags Dodge and her colleagues, including Andy
Myers, a postdoctoral researcher in the Large Pelagics Research Center (LPRC),
are attaching to the leatherbacks aim to fill the knowledge gap on these elusive
swimmers. The tags transmit depth, water temperature and location information
daily via satellite, allowing researchers to gain much-needed insight into
the movement patterns of the sea turtles. Dodge is also analyzing the data
as it relates to oceanographic conditions and jellyfish distribution. The LPRC
tagging team has been joined by investigators from the New England Aquarium’s
rescue rehab group and the Provincetown Center for Coastal Studies, who are
profiling leatherback health and clinical information.
Dodge has tracked the male, who was tagged July 17 about eight miles offshore
in Nantucket Sound, to south of an area called the Canyons, off the continental
shelf. He has traveled about 1100 kilometers in less than two weeks.
“He just took off,” she says. “I think it’s a speed
record.” The females, tagged July 26 and 29 in Vineyard Sound just eight
miles southwest of Woods Hole, are swimming at a more leisurely pace; the first
female is about 250 kilometers from where she was tagged and the second female
swam about 65 kilometers between Tuesday and Wednesday.
Mark Leach, captain of the F/V Sea Holly, poses with "Henry," the
first free-swimming leatherback turtle captured in New England waters. Leach
took researchers from UNH's Large Pelagics Research Center out to tag
leatherbacks with GPS-linked satellite tags. Photo: Kara Dodge, UNH Large Pelagics
Research Center.
Leatherback turtles, which can weigh up to 2000 pounds and are warm-bodied,
like bluefin tuna, are the largest living reptiles in the world. The most migratory
sea turtle species, they travel great distances through a wide range of water
temperatures and to great depths. In the western Atlantic, leatherbacks travel
from their nesting grounds in the Caribbean, northern South America, and southeast
Florida to the productive foraging ground of Atlantic Canada. Leatherbacks
typically come to the waters off Cape Cod from July through October although,
says Dodge, “we’ve never known whether they’re coming to
forage or just passing through.”
Previous tagging efforts by Dodge, Myers and Lutcavage have focused on leatherbacks
that have been entangled in buoy lines of fishing gear. This year, thanks to
additional funding from the National Fish and Wildlife Foundation, the researchers
have been able to take commercial lobster boats out to areas where leatherbacks
have been spotted. This off-shore access allowed Dodge to put a tag on a male;
because they never return to shore after they hatch, little is known about
male leatherbacks.
Off shore and away from their nesting areas, leatherback turtles have no natural
predators except sharks and killer whales; entanglement in fishing gear, ingestion
of marine debris and injuries from boat propellers are the major threats to
their survival. “Understanding where they travel and how they use the
water column will help us mitigate these human interactions,” says Dodge.
Emerging research indicates that climate change likely has a large impact on
the leatherback population, as well.
Lutcavage, who’s been working to better understand New England leatherback
turtles since 1993, is thrilled to see the years of planning come to fruition. “It’s
been a long wait,” she says.
The tagging effort will continue off Cape Cod through September; Dodge hopes
to tag nine more leatherbacks. In addition to the National Fish and Wildlife
Foundation, this work is supported by the National Marine Fisheries Service
Northeast Regional Office and the Cape Cod Commercial Hook Fishermen’s
Association.
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