Wednesday, December 19, 2012

Baby turtle release

It's been snowing here, half-heartedly. There's maybe half an inch of snow melting on the lawn.

Meanwhile, in warmer climes . . .  My son and his family are travelling in Mexico, on their way south. A couple of days ago, in Copala, Guerrero, they were present to watch newborn sea turtles make their way down the perilous sand to the water. These are my daughter-in-law's  photos, posted with permission.

A bowl of new hatchlings.

These are Olive Ridley sea turtles. Every year, thousands of females arrive on appropriate beaches along this coast to lay their eggs, about 100 or more in each nest. The nests are covered with sand and left to hatch, incubated by the warmth of the sun, for about 6 to 10 weeks, depending on the temperature.

This hidden life is not without its perils. Storms and high tides may wash the eggs out of the nests. New waves of females looking for a handy nesting spot often disrupt an established nest. And many animals, from crabs to snakes to foxes, and even humans, dig these eggs up for food. Recently, they are even imperilled by tourists, who dig them out of curiosity.

Known predators of olive ridley nests include raccoons, coyotes, feral dogs and pigs, opossums, coatimundi, caimans, ghost crabs, and the sunbeam snake. Hatchlings are preyed upon as they travel across the beach to the water by vultures, frigate birds, crabs, raccoons, coyotes, iguanas, and snakes. In the water, hatchling predators most likely include oceanic fishes, sharks, and crocodiles. Adults have relatively few known predators . . . Humans are still listed as the leading threat to L.olivacea, . . . (Wikipedia)

The turtle is listed as vulnerable, and several agencies, governmental and non-g. are working together to preserve them. One of the methods used is to collect the eggs from the nests and incubate them in protected hatcheries. When the baby turtles hatch, they are released on their home beach that same day, usually in late afternoon or evening. The youngsters hurry down the beach to reach the sea, as they would have if they had hatched alone. But they are shielded by the human observers from their usual predators, and survive the trip.

Releasing the turtles.

Beginning the trek. Note the legs; they're shaped more like fins, more adapted for swimming than for crawling. The turtles paddle down the beach rather than running.

They're tiny; about three inches long

It's a long way to go, but the end is in sight.

Almost there!

When they reach the water, they pause for a moment, waiting for the next wave, which washes them out to sea.

The hatchlings begin their climb out of the nest in a coordinated effort.  Once near the surface, they will often remain there until the temperature of the sand cools, usually indicating nighttime, when they are less likely to be eaten by predators or overheat.  Once the baby turtles emerge from the nest, they use cues to find the water including the slope of the beach, the white crests of the waves, and the natural light of the ocean horizon.  Artificial beachfront lighting can be a major problem because it attracts these tiny creatures inland away from the water. . . . 
If the hatchlings successfully make it down the beach and reach the surf, they begin what is called a “swimming frenzy” which may last for several days and varies in intensity and duration among species.  The swimming frenzy gets the hatchlings away from dangerous nearshore waters where predation is high. (From SeeTurtles.org)

I would be tempted to "help out" by releasing them a few inches above the water line, but it may be that the initial scramble helps to get their systems working, possibly like the cry of a newborn human is essential to fill the lungs with air. (Just a wild guess, not a hypothesis of any sort.)

My grandsons watching the last few turtles heading for the light across the water.

There's a video that shows the paddling motion of the turtles feet quite clearly, here.

Photos by Angela Bernaldez.

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3 comments:

Powell River Books said...

This is a wonderful post! A long time ago I went down to Baja. We took an inflatable boat and camped along the undeveloped shore areas. This was the first year they completed the paved road to La Paz, so there were only a few people traveling at that time. On one of our trips out in the boat I was looking back and saw what I thought was a scuba diver rising out out the water. It didn't make sense because we knew we are alone. They in dawned on me, it was a huge sea turtle. We had our scuba gear on the trip as well. We saw several manta rays as well. They looked like they were flying through the water. That was a trip to remember. - Margy

Garden Lily said...

Wow, that would be an amazing experience, to watch the hatchling turtles making their way to sea. I bet you wish you were there too! Thanks so much for sharing the photos and information.

Judy said...

Wow!! What incredible photos!! What an experience that must be, to see them racing for the ocean!! I am with you - I would help them to the water, too!!