The thousands of fish that turned up dead along different beaches of the Nicoya Gulf back in February 15, died due to high temperatures and a decrease of oxygen, confirmed the National Animal Health Service (SENASA) after the analysis done by the Center for the Investigation of Microscopic Structures of the University of Costa Rica.

According to the different analysis done, the temperatures in different points of the region were of between 27.5⁰C (81.5⁰F) and almost 34⁰C (93.2⁰F), and the levels of oxygen found were of up to 0.1 milligrams per liter, both this situations create an environment “incompatible with life” for the species of fish found.

SENASA also determined the appearance of a type of seaweed of the type cynobacteria which could have contributed to the mentioned environmental changes. A similar situation was faced in 2002 in Caldera in the Pacific coast when cyanobacterias caused the death of different fish species.

Presence of chemical contaminators and bio-toxins were ruled out.
Although a few days back authorities had recommended not to sell or buy fish originating from this area, they are now confirming that its consumption is safe.