Turtle Beach Arribada

A couple of weeks ago, I introduced many of my readers to the spanish word “arribada” when I referred to the arrival of Costa Rican tourists from San Jose to the beach.   That was tongue in cheek, but this week we have the real thing: Olive Ridley Turtles nesting at Playa Camaronal.

Steve and I drove down in the afternoon – the new culvert/bridge over the Rio Oro makes Playa Camaronal just 26 minutes from our house.  We hit the beach an hour before dusk, giving us time to explore this beautiful, often deserted piece of sand.  That day there were a lot of surfers because Camaronal is one of the major breaks in the area.  Consequently, it’s not a great beach for swimming but there were lots of people hanging out, waiting for the turtles.  playa camaronalolive ridley turtlesThere had been reports of 400 or more turtles that morning, on an incoming tide.  A few trickled in all morning as the tide peaked high at noon.  Then nothing during the heat of the day, but you could see a lot of tracks left over.

Olive Ridley turtlesAt about 5:30PM, as the beach sand started to cool and the tide turned to come in again, the first turtle of the evening appeared out of the surf, seemingly by magic, as the wave receded.  She began her climb – Playa Camaronal is fairly steep and short, so she can get to high dry sand quickly.

arribadaShe spent about 35 minutes, climbing the beach, digging a hole, depositing her eggs, and then returning to the sea.  It’s an amazing thing to watch and there were about 50 of us doing just that.  The park rangers – Playa Camaronal is a protected reserve – insured that we all stayed back to give her room as she dug.  She uses her flippers like teaspoons, scooping out the sand, depositing it at the side, and tamping the inside of the 6” diameter hole.  The experts think the female turtle goes into a trance and is unaware of her surroundings when she lays her eggs, so the rangers allow observers to approach her then more closely from behind.  But, for me, the most moving part of the process to watch was her return to the sea.  The seond wave that reached her brought about 1 ½” water depth and she simply disappeared.  When the foam settled, it was as if she had never been there.

There are 4 kinds of turtles, all of which are endangered, that lay eggs on Camaronal Beach but the Olive Ridley – it’s known locally as the Lora because of its parrot-like beak – is by far the most common.  It is also the least endangered by 4-10 times.  The others that are known to nest there are the Leatherback (Baula), the Black Sea (Negra) and a fourth which I didn’t get the name of.

The female Olive Ridley lays between 80-120 eggs in a hole, covered with 45cm of sand.  She returns to the sea for 15-17 days before digging another nest, possibly at a different beach.  She’ll lay eggs three times in the cycle which occurs every two years.  She reaches maturity at 15 years and may live to be 80 years old.  That’s 32 cycles time 300 eggs.  So why are they endangered?

The rangers tell me that only one in a thousand eggs survives to sexual maturity.  Raccoons and dogs steal eggs at night.  Vultures steal them in the daytime.  But man is still the number one predator, selling the eggs as an aphrodisiac to be eaten raw in bars with beer.  It’s apparently legal to eat turtle eggs in Costa Rica but not to sell them.  Just last week a trafficker who was found with 10,000 eggs, was convicted.  He’ll get a year in prison, a $79,000 fine and confiscation of his house.

The gender of a turtle is determined by temperature – lower temperature near the bottom of the nest results in males while eggs near the warm surface will be female.  There is some evidence that global warming is raising the sand temperature and thus altering the balance of the sexes, in turn affecting the survival of the species.

turtle nestingolive ridely sea turtlesAt the protected beaches, volunteers remove the eggs fairly quickly from their natural nests, even during laying with a bag or bucket, and relocate them to a nursery where they are protected from predators, with fences and netting.  Gestation is approximately 45 days in summer (Nov. – April) and 75 days in winter when the sand is wetter and cooler.  About 80 percent of the eggs hatch and it takes about 4 days for them to all climb through the sand to the surface.  They climb over each other in a kind of ladder/bridge making an air tunnel that allows them to breath.  Volunteers sometimes escort them to the surf.

olive ridley turtles

On a turtle beach, you’ll often see the broken shells from an old nest.

English: Two Olive Ridley (Lepidochelys olivac...

Image via Wikipedia

From the nurseries, the baby turtles are released near the water’s edge to climb down thelast few meters of be beach, so they’ll remember where they were born.  From natural nests, this is their most vulnerable time, when predators can eat them.Arribadas occur monthly at Playa Ostional – also a reserve and about 1 hour north of Samara – when 150,000 to 2,000,000 turtles will try to lay eggs, sometimes destroying earlier nests.  At Camaronal, a few turtles nest every night of the year, but the last arribada (about 4,000 turtles in the daytime and about 8,000 at night) occurred two years ago.  Thus, I’m not sure that what I saw this week really qualifies as a  true arribada.

At Playa Camaronal, the best time to see turtles nesting is at mid tide, either incoming or outgoing, in a full moon.  A guide is often required after dark, charging about $10.00/person and they usually speak only Spanish.  If you go at night, consider going with a tour and leave the nighttime driving through the river to a professional.  William or Carlos will pick you up at our house around 6:30Pm.  Only red-lensed flashlights are allowed on the beach, to protect the night-vision of the turtles.  Be prepared for a long walk in the dark as you search the length of the beach for the tracks that lead from the water to the nest in the upper part of the beach.  But if you’re lucky, like we were, you can sometimes see them in the daylight.

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3 comments
  1. ronandjoan said:

    Lavae, I love your write up and it makes very clear what we saw last night. I’d like to use your phto on my BLOG….
    Joan

    • lavaeha said:

      sure, you can use this photo.
      What is your blog address?

  2. Steve said:

    Nice article.

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