A study by the marine conservation organization Innoceana showed that 80 percent of the corals on the island are suffering from bleaching, caused by other factors as a sign of a stress response, or an increase (more usually) or decrease in water temperature.
The site, which has been declared a Biosphere Reserve, is located about 20 kilometers west of Drake Bay on the Osa Peninsula and has an area of about 320 hectares.
The ENSO phenomenon causes an unusual warming of the surface of the Pacific Ocean and together with the effects of climate change, the temperature of the sea changes significantly, according to an article published by Delfino.
These conditions stress the corals, forcing them to expel the zooxanthellae (organisms that provide carbohydrates to corals through photosynthesis) that sustain them, causing them to discolor.
Innoceana remembers that many species such as sharks, whales, turtles, rays, whales, and other migratory species pass through Caño Island.
Since June, experts have been constantly monitoring the sea temperature to understand and minimize the impact of high temperatures, with devices recording a maximum of 31.6 degrees Celsius.
Researcher Kerlyn González commented that these high temperatures were observed not only in the dawn hours but also in the early morning hours when generally there is no sunlight and cooler conditions are expected.
Experts from the Marine Sciences Research Center of the University of Costa Rica explained that corals usually live in warm waters between 24 and 28 degrees Celsius because at these temperatures they grow and reproduce faster.
For his part, the founder of Innoceana, Carlos Mallo, explained that since 2018 they have been studying the corals of that island and creating 3D models, but they never thought that in 2023 they would all be white. “It’s frustrating,” he added.