Saturday, September 22, 2012

Mexico And The Turtle


This time of year is nesting or “clutching” season for sea turtles and I am reminded of a wonderful day spent on the beach at Tronconus, just outside Ixtapa . Todd and I were invited to a party at a cute little casita right on the beach. It was a small casual party with a diverse group of people and the conversation was lively and very interesting. One of the Mexican guests brought ceviche, made from a family recipe, that was incredible and  a lady from Alaska brought smoked salmon.

There was also a fellow there who was a bit of an expert on reptiles which, as the day progressed, turned out to be very fortuitous. Shortly after our party began there was a commotion at a cabana up the beach a little ways. Someone was hollering about una culebra, a snake. Hunter, the reptile expert, was off in a flash and returned with a lyre snake, pronounced “liar”. After we had all oo’ed and aw’ed over and petted the lyre, Hunter put it in a bag to be returned to the jungle sometime later.


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The Beautiful Lyre Snake


The party was definitely off and running, and shortly thereafter, so were we. Not long after the snake went into the bag someone noticed a large sea turtle climbing up a sand dune not far from the casita. Naturally, beers in hand, we all had to rush to check it out. As it turned out the turtle was completely oblivious to all the watchers and continued on until she had found what she felt was the right spot for her nest. She began to dig.


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Maternal Instinct


The next couple of hours proved to be really fascinating, and made all the more interesting by having someone with us who could explain about turtles as the process progressed. To our amazement mother turtle dug a hole about 12 to 18 inches deep. When this was done she then started to dig a smaller hole, cupping her rear flippers like a sand spade. This was incredibly slow and arduous work and I was amazed by her unwavering determination. I’ve heard that sea turtles go into a kind of trance during nesting and can’t be disturbed by anything around them. Apparently this is not actually the case, but it definitely looked that way at the time.


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Kids learning about conservation


I learned that 6 of the 7 species of sea turtles are found here in Mexico, that they are found in all the world’s oceans and that most of them are endangered. I knew that sea turtles spend most of their lives in the ocean and that they lay their eggs on land but I didn’t know that they always return to the place where they were born, to lay them. They can live up to 200 years and apparently have an extraordinary sense of time and location, possibly due to the fact that they are very sensitive to the Earth’s magnetic field. This also may be how they navigate.

Watching this process, I couldn’t help but think about the fact that turtles have lived for 100 million years and are now being pushed to extinction. There are many reasons for this but probably the main one is living with humans and the changes we have wrought in their environment. Turtles and manatees are about the only animals that eat sea grass, which like our lawns, needs to be cut short to thrive and spread across the sea floor rather than just growing tall in clumps.

You’re probably thinking, “ and this is important because?”  I was. It is important because these sea grass beds provide breeding grounds for many species of fish, shellfish and crustaceans. A small change in the ecosystem can create a domino effect. I think the scuba diver in me is surfacing….so to speak.

However, I was very happy to discover that conservationists all over Mexico are working to keep the sea turtles from extinction and some of them were just down the beach from us. We all stood around watching and waiting for momma turtle to finish her task and then ours would begin. Finally she had carved out her second, smaller hole where she laid her eggs. They are like soft warm ping pong balls, and flexible so they don’t break as they fall into the hole. Then she began to slowly refill the hole and pack down the sand.


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And Then She Was Gone


Turtles lay about 80 to 120 eggs per clutch depending on the species. In this clutch there were 90. There was a turtle nursery about 100 yards down the beach from the nest and we planned to dig up the eggs an bring them to the nursery where they would be reburied in a fence enclosed area and watched by the conservationists there. The incubation  period of the eggs is about 45 to 60 days, with the temperature of the sand governing the speed of the embryo’s development.

The survival of an egg clutch is precarious to say the least. Overhead the sea gulls and pelicans were circling and on the beach a few dogs were doing the same. Thankfully a couple of people from the nursery arrived to guide us through the extraction process. Even though we had all watched the birth we had a hard time finding the actual egg bundle. Mother turtle had done an excellent cover-up.


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The eggs were right under that can of beer

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 Pay Dirt!

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90 Future Turtles

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What? No Leftovers?


Without the help of the conservationists, and bystanders, the chance of even a few of these eggs making it to adulthood is very slim. And for those few that do their future is uncertain.

Sea turtles are actually a part of 2 ecosystems. The beach/dune system and the marine system. Turtles will lay 3 to 7 times during the nesting season and over a 20 mile stretch of beach leave about 150,000 pounds of eggs per season. Not all the nests will hatch, not all the eggs in a nest will hatch and not all the hatched turtles will survive.

This all leaves nutrients in the dunes which are hard pressed to get them in other ways.
With these nutrients dune vegetation becomes stronger providing a root system that helps prevent sand erosion on the beaches. Sea turtles play a large part in supporting both these fragile ecosystems.

This concludes the science portion of this post and we now return you to the party. No, wait… the party sort of degenerated from there so I think we’ll leave it at that.

2 comments:

  1. You have your turtles. I have my crocodiles.

    ReplyDelete
  2. Yes, but I have to drive all the way to the beach to see turtles, your crocodiles are right outside!

    ReplyDelete