- In recent days, different tour guides and residents of the Drake community have found up to 12 dead black turtles (Chelonia mydas) on the beaches of the Osa Peninsula.
National alert due to red tides: 12 turtles found dead on South Pacific coasts
As a result of the recent turtle strandings, different national and international marine conservation organizations such as Innoceana, CREMA, Alturas Wildlife Sanctuary and other conservation projects such as the Asociación Conservacionista de la Tortuga Marina del Progreso (ACOTPRO) are joining forces to try to find the cause of death of these marine reptiles.
Although the cause of death is yet to be confirmed, one of the most commented hypotheses is that they have been affected by the great wave of red tides that is currently invading the waters of Costa Rica. Red tides are not a new enemy in Costa Rica and the rest of the world, and in fact they may have natural causes, but in recent years their frequency and impact have increased markedly and it no longer seems to be such a natural process.
During the last 7 months, large masses of red tides have been sighted in the waters of the North Pacific and Central Pacific of Costa Rica; and since the last month, huge outcrops of red tides have also been experienced in the South Pacific coasts, especially in the Osa Peninsula and Caño Island. The impact has been so strong that some Costa Rican marine conservation organizations such as Innoceana, UESPRA, CREMA and the Federation of Artisanal Fishermen and Molluscists of the Gulf of Nicoya, have established a Facebook Group called “Marea roja – Costa Rica | Red Tide Watch Report” where the community can send their reports of red tides and animals affected by it, which is allowing a better understanding of the phenomenon.
During these months, numerous animals affected by red tides have been found both on the beaches and under the sea. Red tides massively affect many types of invertebrates, for example corals, since an increase in bleaching has been observed in them due to lack of light, and there have also been massive arrivals of dead sea urchins on the beaches. . Many of these invertebrates are filter feeders such as sponges and various molluscs, and these are usually the first to be contaminated by the dinoflagellates that form red tides. After the invertebrates and filter animals, the next to be affected are the animals that eat them, such as fish, so it was not surprising that after so many weeks of red tides being affected, many species of dead fish began to be found, generally juvenile reef fish as well as commercial species. These massive and prolonged outcrops now seem to be affecting larger animals and higher up the food chain, so much so that even dead sharks have already been found. The case has already become totally alarming with these latest massive encounters of dead sea turtles, not only in the South Pacific, as some dead turtles have also been reported in the Guanacaste sector.
Whether or not they are the cause of the death of these turtles, it is a certainty that red tides are greatly affecting marine life. Little can be done right now to stop the current wave of red tide present in the waters of Costa Rica, but measures can be taken to prevent it in the future. Without adequate legislation that prohibits certain agrochemicals and a clear social awareness that promotes more sustainable practices, this trend in the ocean will only increase.