Saturday, January 17, 2015

Loggerhead's 'Lost Years' During Migration Discovered

Loggerhead sea turtles have long been famous for their epic migrations, traveling for thousands of miles across the open ocean. However, there has been a gap in the record of their travels, that is, until now since NOAA researchers discovered evidence of what are known as "the lost years," a new study says.

loggerhead sea turtle
North Pacific loggerheads typically nest on beaches in Japan where they give birth to young hatchlings, which then disappear into the North Pacific and later show up about 6,000 miles away off Baja California. But how do these turtles get from Point A to Point B? This mysterious lapse in time has long been referred to by scientists as "the lost years."
In a stroke of good fortune, late last year scientists with the NOAA Fisheries conducting a marine mammal survey happened to stumble upon a band of 70 young loggerheads more than 200 miles off the Southern California coast. They believed this group to be of the lost years.
"It's one of those great 'aha' moments in science," researcher Scott Benson said in a statement. "We've always known they were out there somewhere, we just didn't know where."
So why exactly is it important that scientists know the exact movements of these migrating turtles? The NOAA-led team believes their study has important implications for the conservation of loggerheads, a species threatened by the fishing industry.
"If we can predict where loggerheads are going to be and when, we can tell where it's safer to fish," explained marine ecologist Jeffrey Seminoff.
According to the Sea Turtle Conservancy, there are an estimated 40,000 to 50,000 nesting loggerhead females worldwide, with populations steadily declining mostly from incidental capture in fishing gear, but also because of pollution and development of their nesting habitat.
But with these new findings, loggerhead sea turtles may be able to get some help.
Biologists have known for some time that loggerheads prefer warmer waters, so seeing them off the coast of California when temperatures are high isn't all that unusual. One theory was that turtles feeding off southern Baja ventured hundreds of miles north toward California during warm conditions.
However, this theory doesn't add up considering the recent swarm of juveniles was spotted heading in the opposite direction, not to mention that they were smaller and younger than turtles commonly seen of Baja. The only explanation, researchers say, is that these turtles were still migrating south toward Mexico via ocean currents, making them "lost year" loggerheads.
"This is one of the best discoveries we've had in years in terms of understanding the lives of these turtles," Seminoff added.
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Original article at