After eight months at home in Nebraska, we flew back to Trinidad on May 2nd, arriving at 10:15 p. m., and stayed in an airport motel. By noon on the 3rd, we had taken a taxi and returned to Power Boats Yard in Chaguaramas Bay. While Wight Skye was still on stands in the yard, we stayed in a small efficiency apartment in the boat yard. Right away this day, we ran into our dear friends from England, Paul and Jane, S/V Shian. We made plans to meet in the evenings for the next few days, before they haul Shian and fly home. Meanwhile, I made arrangements with a couple of yard workers to begin cleaning up Wight Skye, waxing her cabin, decks, and stainless steel. We also installed a couple of teak pads in the bowsprit to keep the anchor rodes from contacting the bit of topsides paint they seem to chip and scratch sometimes. I had a diesel mechanic look over the engine again concerning a fuel pump problem. He found a wire had been knocked loose from the temperature sender. This is part of the safety shutdown system on the engine that disengages the fuel pump for high temperature or low oil pressure.
On the next evening, Wednesday, May 4th, we arranged to ride with Jesse James’ Members Only Maxi Taxi to travel across Trinidad to the Atlantic Shore at Maturo Beach and watch Leatherback Turtles come ashore to lay eggs. This beach claims one of the largest populations of Leatherback Turtles in the world during their egg laying season. This clearly will have been the ultimate experience of the cruising season if not of a lifetime. We were awestruck.
The Leatherback is the largest of all sea turtles.1 The species is unique in having a soft covering and no shell. The Leatherback is also the fourth largest of all reptiles, the three larger all being crocodilians. The females of these turtles do not reach sexual maturity until they are at least six years of age. Thereafter, they tend to lay eggs every second or third year, laying up to nine clutches of about 115 eggs each during their laying year. The eggs hatch in about 60 to 70 days. About 85% of them are viable. The females appear to have a sperm storage mechanism, so that they do not need males between successive batches of eggs, although the Trinidadians that watch over this beach say that there are males in the water just offshore. Clearly, the reproductive strategy here is that of huge numbers of offspring followed by high mortality of eggs and hatchlings. Survival rate is something like one to two percent.
The females only come ashore during the night. We could not use lights or take flash pictures as they came up out of the surf, because white lights confuse and disorient them. It takes about 30 to 45 minutes for each female to lumber and struggle up the beach to a point about 40 yards above the surf line and five feet above sea level. Then, she spends another 45 minutes or so, using her flippers to excavate a large nest hole. She removes about two thirds of a cubic yard of sand. Then, she drops her bottom into the pit and lays her clutch. While she’s laying, we were allowed to use flashlights and take flash pictures, as she goes into a trance and isn’t bothered. When she’s done laying, she buries them with the sand she had removed and very carefully pats down the cover. Then, we must turn off all lights again lest we disorient her as she makes her way back down the beach and into the surf.
The turtles we saw were a good six feet long, four feet wide, and would have weighed not much under a thousand pounds. A young female just sexually mature may weigh 550 pounds and be around three and a half feet long. The largest commonly observed are six and a half feet and weigh up to 1,500 pounds. The largest ever measured was ten feet long and 2,019 pounds. When not laying eggs, the turtles are strictly pelagic. They’ve been observed in all seas and from the surface to about 5,000 feet deep. They are fast swimmers, having been observed swimming at 21.92 miles per hour. While it is not known if they actually migrate, a radio-equipped Leatherback was observed to have swam 12,427 miles over 647 days. They are endothermic and maintain an internal body temperature up to 32.4 degrees higher than cold seawater. Clearly, they would not be doing that in our 85 degree Atlantic Tropical water. The earliest fossils of Leatherbacks date to the Upper Cretaceous, about 110 million years ago, quite a successful species. It’s just such an awesome sight to see these great, ancient reptiles come lumbering up out of the nighttime surf.
1. Scientific information here is from our guide and from Wikipedia and our own observations.
No comments:
Post a Comment