BY GRACIELA TIBURCIO
During this past week, dozens of Olive Ridley sea turtles arrived to lay their eggs on Medano Beach, our busiest. The curiosity of locals and tourists scared some away, but restaurant personnel protected them, shooing people away until members of the Navy and National Guard arrived to protect them. Almost 200 nests were recovered and taken to a safe nursery. Los Barriles residents have also reported both, sea turtle arrivals and eggs hatching by the dozens.
The Olive Ridley Turtle is one of the species of sea turtles that are characterized by showing different types of reproductive strategies, solitary nesting, nesting in groups or a combination of both (although other species such as the Kemp’s ridley turtle have also reported this). The reproductive behavior of mass nesting is called “arribadas” and is determined by the presence of hundreds or thousands of turtles nesting synchronously for several consecutive days on a specific beach, which becomes one of the most spectacular natural phenomena. The hundreds of thousands of eggs that are deposited during these events represent valuable amounts of energy and nutrients for unproductive systems such as sandy beaches. This is why the Arribada beaches have great ecological importance since the most important colonies of olive ridley turtles in the world nest there en masse, including beaches in India, Costa Rica and Mexico. In Mexico, Escobilla Beach stands out; Oaxaca has the largest number of nesting sites in the world, and it is reported that up to 30,000 turtles can spawn in one arribada. It must be taken into account that an arribada can last around 6 days (not every day with the same intensity).
Today, Mexico has the beach with the largest arribada in the world, which is Escobilla, Oaxaca. Although not all beaches or all populations of olive ridley turtles make arribadas, as they are the most numerous and widely distributed species in the world, by laying their eggs on the beach, sea turtles transport vital nutrients from productive marine ecosystems to sandy beaches, which are habitats with few nutrients. Through the processes of predation and nutrient recycling, the energy from the eggs contributes to sustaining populations of plants and animals in terrestrial habitats near the nesting beaches. The beaches of arrival have an underlined ecological importance, as well as a tourist importance, which if the activity is not regulated, becomes a negative impact capable of changing the behavior of the animals derived from the disturbance and collapsing the arrival as happened in Costa Rica in 2015.