Saturday, January 20, 2007

Sea Turtle Rescue in Texas

Today the New York Times published a story about the current efforts to help some young Green Sea Turtles. This rescue is important since Green Sea Turtles, chelonia mydasare, are considered endangered in Florida waters and the Pacific Coast of Mexico including the Gulf of California. They are listed as threatened everywhere else. In a nutshell, here's what happened:

Young Green Sea Turtles, born last spring off the coast of Yucatán in Mexico, were stunned by the cold in the rapid temperature drop earlier this week. Water temperatures fell 18 degrees in 48 hours. Since turtles are cold-blooded and can't generate their own body heat, this drop in temperature sent them into a hypothermic state. They began washing ashore in South Padre Island, Texas. Animal rescuers were afraid the sluggish turtles would die from the cold or be eaten by sharks, their only predators, so between January 17 and 19, 36 nearly immobile turtles weighing anywhere from 3-65 pounds were scooped up by volunteers and staff of Sea Turtle, Inc. The turtles were scrubbed and warmed and are being held at their facility until weather permits returning them to the sea. The webcam at Sea Turtle, Inc. lets you view the turtles in their temperature-controlled tubs. Check it out!

Green Sea Turtles are amazing creatures. The are named for their green body fat. Although we don't really know their lifespan, we know they take 15-20 years mature. By then they are four feet in length and weigh 250-450 pounds. They are the largest of all the varieties of sea turtles. They are found all over the world in tropical and subtropical waters. They are known to swim as far as 1400 miles between their feeding grounds and the beaches where they lay their eggs. Females lay 75-150 eggs per clutch and can lay as many as seven clutches in a season. Turtles lay so many eggs because so few of the young survive. How about this for a rough start: After a two-month incubation period the hatchlings break out of their eggs. That's just the first step. Next they have to dig out of the hole in which the clutch of eggs was buried by the mother turtle. Believe it or not, they do this as a group! Working together, they scrape away at the top of the nest until they are about an inch away from the surface of the beach. The hatchlings nearest to the surface actually stop digging if the sand feels hot, indicating that it may be daytime. They wait to resume digging until the sand feels cool, indicating nighttime. This instinct to wait for cool sand helps them avoid predatory crabs and birds as well as death by overheating. Once on the beach, they find the sea by navigating toward the brightest horizon. (Artificially lit beaches can mean death for turtles, as the lights make them lose their way to the sea.) Once they hit the water, they have to swim continuously for 1.5 to 2 days to reach their feeding grounds. They do this on their own, again as a group, with no mother to guide them. In the water, some of them become snack food for sharks and carnivorous fish. In the end, only a few baby turtles from each nest reach adulthood. Their very long lifespan counterbalances the high mortality rate of the hatchlings.

The hatchlings now in South Padre Island had arrived safely at their feeding grounds in Mexico. They should have been "home free," but the sudden cold transformed their warm haven into a death trap. They might have all died, were it not for the rescuers.

The last time it was cold like this was 2004; before that the 1980's. The polar bears' ice floes in the Arctic are melting and the turtles' tropical feeding grounds are freezing. What's wrong with this picture? As humans and guardians of the planet, I hope we can figure out how not to destroy the marvelous wildlife whose world we share.

© 2007, Linda Mason Hood
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1 comment:

Kipluck said...

I think this is just so fascinating! I got to meet my first in the wild sea turtle over Christmas in Hawaii and was just enchanted (got video of it on my blog!). Of course, I already loved turtles, that's why I saw your blog... I am in the RES group on Yahoo!