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Turtles in trouble: can tracking sea turtles help save them from extinction?

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This July, crowds gathered on a beach at Florida's Barrier Island Center to cheer on an unusual athlete--a female sea turtle. With much fanfare, she scuttled out of a starting gate, down the sand, and into the Atlantic Ocean. She was one of 10 turtles leaving from various beaches competing in the Sea Turtle Conservancy's annual Tour de Turtles. The race is meant to raise awareness about the plight of loggerhead, green, olive ridley, and leatherback turtles--all of which are threatened or endangered.

Fans followed the turtles' journeys online to see which one swam the farthest. This was possible thanks to electronic tracking devices affixed to each racer's shell. These tags serve another important purpose too. They allow scientists to learn about the animals' migration routes and marine habitats as they travel thousands of miles to feed, mate, and nest. They also reveal the obstacles turtles encounter along the way, so protective measures can be put in place.

Turtles' biggest threats come from human activities, such as fishing, pollution, and development. Dangers like these have taken their toll on sea-turtle populations. It's estimated that fewer than one in 1,000 turtle hatchlings, or newborns, survive to adulthood. "We need to know more in order to better conserve these animals," says Kate Mansfield, a biologist with the National Oceanic and Atmospheric Administration's fisheries service in Florida.

JOURNEY TO ADULTHOOD

Every summer, thousands of female sea turtles dig nests on sandy beaches. Each lays hundreds of soft-shelled, golf-ball-size eggs (see Life Cycle of a Sea Turtle, below). The warm sand incubates the eggs until they are ready to hatch. When the tiny turtles emerge, they instinctively scramble for the surf, then swim frantically into the open ocean.

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Scientists don't know exactly how long young sea turtles spend in the ocean's pelagic zone, or upper layer of water, away from the shore. But when the turtles reach approximately the size of Frisbees, the "teens" return to coastal areas, where they will grow into adults. Depending on the species, juveniles can take anywhere from 10 to 30 years to fully mature into hefty 45 to 450 kilogram (100 to 1,000 pound) sea turtles.

As adults, females return to nest at the same stretch of beach where they were born. The generation of hatchlings they produce will repeat this cycle all over again.

FOLLOWING TURTLES

Scientists have many questions about sea turtles' life cycles, especially in the earliest stages. "Very little is known about the youngest juvenile turtles when they are in the open ocean," says Mansfield. "Where are they going, how are they getting there, what are the risks in between, and how do they interact within their environment?"

To learn more, Mansfield and colleague Jeanette Wyneken, a biologist at Florida Atlantic University, wanted to see if it was possible to track baby turtles in the high seas. They affixed the smallest trackers available to tiny, 4-month-old loggerheads--the youngest ever tagged-and released them off Florida's eastern coast. Similar devices have been adapted to track all types of hard-to-follow animals (see Tag, You're It!, right).

Each time the turtles surface for air, satellites orbiting the planet pick up signals from their transmitters. The data are beamed to a computer and mapped to show the turtles' movements. The team was able to monitor each teensy swimmer as it made its own round-about way to the open ocean (see map, left). "It blows my mind that these little guys and gals are out there in the middle of nowhere," says Wyneken.

TRAVEL HAZARDS

Tracking devices have already provided insight on where turtles run into human-caused trouble. Last year, for instance, tagged leatherbacks swam right into the heart of the Deepwater Horizon oil spill in the Gulf of Mexico. It turns out that the area is a vital foraging ground for the turtles. Instead of finding food, many sea turtles ended up being coated by the oil slick.

Tagging can also help conservationists learn whether turtles travel through commercial fishing areas, where they can be netted accidentally as bycatch. "Then we can work with fisheries to concentrate their efforts where turtles aren't located during certain times of the year, says David Godfrey, executive director of the Sea Turtle Conservancy in Florida.

On land, a major threat to turtles is the destruction of nesting sites by beachfront development. The turtles are also attracted to the bright light of the buildings, which causes them to navigate away from the water. "They go the wrong way and end up in parking lots, swimming pools, and streets," says Godfrey. To combat these problems, his group works to preserve nesting beaches and dim artificial lighting.

One place where sea turtles and people live together successfully is Tortuguero, Costa Rica, a major nesting spot for green turtles. People there used to harvest nearly every turtle to sell their meat and eggs. Then the Sea Turtle Conservancy helped the town develop an ecotourism program. Its economy is now supported by visitors who come to turtle-watch. "People are fascinated to see sea turtles up close," says Godfrey. Now the race is on to save them.

[WHAT DO YOU THINK?]

Turtles can become ensnared in or choke on plastic debris in the ocean. How could tracking turtles help protect them from plastic pollution?

LIFE CYCLE OF A SEA TURTLE

During the summer, female sea turtles return to the same beaches where they were born to lay their eggs. The hatchlings that emerge must survive on their own in the ocean until they reach adulthood.

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[1] Females come ashore on sandy beaches to lay several batches of eggs.

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[2] Eggs hatch in about 60 days and hatchlings head for the sea.

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[3] Young turtles spend several years in the open ocean.

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[4] Juveniles return to coastal habitats, where in 10 to 30 years they'll mature into

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[5] After adults breed, females return to nest at the beaches where they were born.

RIDING THE CURRENT

This map shows the paths (colored lines) of tagged baby loggerhead turtles as they hitch a ride on the North Atlantic gyre. This circulating ocean current flows around the Sargasso Sea, a floating-seaweed jungle where young turtles forage for food.

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Turtles in Trouble

STANDARDS

NATIONAL SCIENCE EDUCATION STANDARDS:

Grades 5-8: Populations and ecosystems

Grades 9-12: Behavior of organisms

COMMON CORE STATE STANDARD: WRITING IN SCIENCE:

9. Draw evidence from literary or informational texts to support analysis, reflection, and research.

OBJECTIVE

Understand the life cycle, migratory routes, and habitats of endangered sea turtles. Examine the human-made threats to sea turtles and some success stories.

BEFORE READING

* How many species of sea turtles are there? How many live in U.S. waters? (Seven species total. Six live in U.S. waters. The seventh--the flatback sea turtle--is found only in Australian watery.)

* Do sea turtles spend their entire lives at sea? (Males do, but females return to the shores where they were born to nest.)

* What human activities threaten sea turtles? (oil spills, commercial fishing, destruction of nestling sites, light pollution, marine debris, poaching, and many others)

LESSON

1. Go to www.scholastic.com/scienceworld. Open the digital edition to pp. 10-11, and have students do the same in their magazines. Call on a volunteer to read the headline and the deck. As a class, predict what the story is going to be about. Have another student use the highlighter tool to highlight the word extinction and ask the class what that word means.

2. Write the correct definition on a digital "sticky note." (the dying out or disappearance of a species) Ask a student to read the first two paragraphs of the article to set the scene.

3. Pass out the "Understanding Sea Turtles" work sheet from the online skills sheet database. Have students work in cooperative groups to skim the article and generate a list of vocabulary words to define. Then have them read the text and complete the work sheet.

4. Call a representative from each group to the front of the class to type their prediction for the most positive change in human activity onto a digital sticky note. Then, lead a discussion of the predictions shared by each group. Would implementation require new legislation? Would an education campaign be the best way to change people's activities?

DISCUSSION

Read the text in the box labeled "What Do You Think?" oil page 13: "Turtles can become ensnared in or choke on plastic debris in the ocean. How could tracking turtles help protect them from plastic pollution?" Discuss what your students think about the problems with plastic pollution. Then use the Earth Science activity below to delve further into the topic.

ASSESSMENT

Go over the class's responses to the "Understanding Sea Turtles" work sheet. Did they come up with inventive solutions to the turtles' plight'?

DON'T TEACH BIOLOGY?

Go to www.scholastic.com/scienceworld to download these assessment skill sheets instead:

EARTH SCIENCE: PLASTIC POLLUTION

Plastic debris threatens not only turtles but all marine life. Read lids passage to learn more about plastic debris and how it harms sea creatures.

PHYSICS: TRACKING TURTLES

You read about how scientists are using high-tech trackers to learn more about baby loggerheads. Use this work sheet to reorder the major steps in tracking turtles.

RESOURCES

* VIDEO EXTRA: Watch an introduction to the Tour de Turtles at: www.conserveturtles.org/seaturtletracking.php?page=tourdeturtles.

* Visit NOAA Fisheries' Office of Protected Resources sea turtle Web site at: www.nmfs.noaa.gov/pr/species/turtles.

* Read sea turtle news at: www.seaturtle.org.
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Title Annotation:BIOLOGY: LIFE CYCLES
Author:Crane, Cody
Publication:Science World
Geographic Code:1USA
Date:Sep 5, 2011
Words:1598
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