JIJITANG2014-07-29 6:26 PM

SEA TURTLES RETURN TO WHERE THEY DRIFTED AS BABIES

Where little sea turtle hatchlings drift in ocean currents determines their migrations and selection of feeding sites as adults, new research shows.

When they breed, adult sea turtles return to the beach where they were born. After breeding, adult sea turtles typically migrate several hundreds to thousands of kilometers to their feeding habitats.

There’s been little information about how turtles choose their feeding sites, though. For example, some turtles migrate to feeding habitats thousands of kilometers away, while other turtles don’t migrate or feed in the open ocean.

SATELLITE TRACKING

The study looks at what habitats the turtles would have experienced as juveniles. Newborn hatchling sea turtles are too small to track with satellite tags. However, when they emerge from their eggs, they head to the ocean and drift with ocean currents to their juvenile development habitats.

The researchers combined all the available satellite tracking data on adult turtles with models of how the world’s seawater moves past nesting sites to study where the hatchling sea turtles drift.

By comparing global patterns in the migrations of all satellite tracked sea turtles with global hatchling drift patterns, they showed that adult sea turtle migrations and foraging habitat selections were based on their past experiences drifting with ocean currents.

“Hatchlings’ swimming abilities are pretty weak, and so they are largely at the mercy of the currents,” says Rebecca Scott, leader of the study in Ecology.

“If they drift to a good site, they seem to imprint on this location, and then later actively go there as an adult—and because they’re bigger and stronger they can swim there directly.

“Conversely, if the hatchlings don’t drift to sites that are suitable for adult feeding, you see that reflected in the behavior of the adults, which either do not migrate or they feed in the open ocean, which is not the normal strategy for most turtle species,” explains Scott, who is based at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany.

SOLO TRAVELERS

Many animal groups undertake great migrations, and the process of learning where to go on these travels can take several forms. For example, some juvenile whales and birds learn migration routes by following their mothers or more experienced group members, while other bird and insect species seem to be born with the information or a map sense that informs them where they should migrate.

However, neither of these strategies works for turtles. Once the adult female has laid her eggs on a beach, her involvement in her offspring’s development ends. When the hatchlings crawl down the beach into the water, they are on their own; there is no experienced turtle to follow, and they go where the ocean takes them.

“Although it is known that ocean currents have a large influence on the dispersion of small planktonic organisms, these findings reveal ocean currents also directly shape some the migrations of some of the largest, most powerful long distance migrants in the animal kingdom,” adds Bob Marsh of the University of Southampton, who was Scott’s supervisor and coauthor of the study.

Smith’s NERC PhD studentship and a postdoc position funded by The Future Ocean Cluster of Excellence supported the work.

Original Article: 
《Ontogeny of long distance migration》, Published on Journal 《ESA Ecology》in May 2014. 

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

JIJITANG

0 Following 3 Fans 0 Projects 310 Articles

SIMILAR ARTICLES

Changes to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) have resulted in families eating more fruits and vegetable

Read More

In contests drawn from game theory, chimpanzee pairs consistently outperform humans in games that test memory and strategic thinking.A new study, condu

Read More

Publishing is one of the most ballyhooed metrics of scientific careers, and every researcher hates to have a gap in that part of his or her CV. Here’s

Read More

Pornography triggers brain activity in people with compulsive sexual behaviour -- known commonly as sex addiction -- similar to that triggered by drugs

Read More

In a recent survey, academic staff at the University identified the interrelated skills of writing and reasoning as the two most important skills for s

Read More

In a recent survey, academic staff at the University identified the interrelated skills of writing and reasoning as the two most important skills for s

Read More

Reading cautionary tales like The Boy Who Cried Wolf and Pinocchio to little kids might not be the best way to teach them to tell the truth.New researc

Read More

Those flat, glassy solar panels on your neighbor’s roof may be getting a more efficient makeover, thanks to a new class of solar-sensitive nanoparticle

Read More

Physicists have overcome a major challenge in the science of measurement using quantum mechanics. They’ve used multiple detectors to measure photons in

Read More

If you want to slow down long enough to smell the proverbial roses, you might want to move to a neighborhood with fewer drive-thru restaurants, researc

Read More