Turtle Nesting Season
This is the time of year when the Olive Ridley Turtles (Lepidochelys olivacea) come ashore to lay their eggs. Here in the beaches around San Carlos they do not nest in large numbers, so there is no turtle-watching tourism, but it seems the number of nests is increasing.
The turtles hang around near the nesting sites, feeding and mating for about two months before the females come ashore to lay their eggs, so there is always a chance you will see one while snorkeling or paddling quietly around local waters.
Olive Ridleys aren’t big, as sea turtles go, about 60 cm or two feet in shell length, so watch for a head about the size of a fist, poking out of the water. When they come up for air they stick their heads above the surface several times, gulping air, before they submerge. Once they go down, they may remain submerged as long as several hours, depending on how active they are.
All sea turtle species are in danger of extinction, mostly due to human harvesting of the eggs and adult turtles. Olive Ridleys are actually the most abundant sea turtle, worldwide, but are still listed as vulnerable by the International Union for Conservation of Nature (IUCN). There is an international treaty called the Convention on Trade in Endangered Species, commonly known as CITES. Under this treaty, of which Mexico, Canada and the USA are all signatories, the trade in listed species of plants and animals, and any parts, including a shell you may find on the beach or in a market is strictly controlled. Taking a sea turtle or even a piece of a shell across the border into the U.S. or Canada will land you in very hot water, and may result in heavy fines or even jail time.
Once they reach maturity, these turtles nest annually, typically in large numbers called arribatas. Here in San Carlos, the turtles are so few in numbers that nesting occurs singly. Turtle mortality is highest in the egg stage. Nests sometimes drown in extra-high tides, can be exposed by beach erosion from storms, or be dug up by egg predators such as raccoons, coyotes or feral dogs.
The eggs hatch after about two months incubation, usually at night. The newly-hatched young dig their way to the surface, and head to the sea, guided by moonlight sparkling of the surface. They have to get into the water before first light. If they are caught out in the open, they are quickly gobbled up by vultures, frigatebirds, gulls and ravens.
Annette Felix is a local woman who is spearheading a campaign to protect these wonders of nature. She has organised support to patrol the beaches, looking for tracks or any evidence of nest-building. She has also recently put together a flyer warning people of the possibility of nests on the beach, and suggesting things they can do and should not do, in order to maximise the survival of eggs and hatchlings.
Because the eggs are just under the surface of the sand, they can be crushed by a careless pedestrian or under the wheels of an ATV or truck. Motorised vehicles are banned by law from the beaches here, but this rule is poorly enforced and often ignored. So the first rule is; be careful where you walk, and try to discourage motorists from using the beach as a racetrack.
When the hatchlings emerge, they may be misdirected by lights from homes and streets, and head away from the sea. By the time they realise their mistake, they are a long way from the sea and are vulnerable to predators. So the next rule is: lights out. Keeping exterior lighting to a minimum is crucial to the survival of hatchlings.
These animals are adapted to swim in the sea and are very good at it. But travelling overland is a tiring and difficult venture for a female turtle carrying a heavy load of eggs. Beached boats, chairs, trash and even sand castles and pits dug in the sand by happy children can be a serious impediment to females and also to the hatchlings heading for the sea. So the next rule is: keep the beach clean and free of trash and obstacles. Fill in your pits and flatten your sand castles when you are finished with them.
Following these simple rules will contribute to turtle conservation, and help to ensure that these magnificent animals which have been on the earth for millions of years, will still be here for your grandchildren to see and enjoy.
Photos from National Geographic.