Coral bleaching detected in Caribbean at Bocas

Example of bleaching coral in Bocas del Toro. Photo: Smithsonian Tropical Research Institute photo

A warning message just was issued from Bocas del Toro on coral bleaching and invertebrate mortality. Although the National Oceanic and Atmospheric Administration had issued a warning on above-average sea surface temperatures in the wider Caribbean region in July, there was no indication in Panamá of the rising temperatures until mid-September.

A team of Smithsonian scientists and local dive operators first noticed the bleaching and mortality event in the surrounding waters of Istmito in Isla Colon, Bocas del Toro. The water showed an abnormal warming to an extreme of 32 C (89.6 F).

This area is located in front of the Smithsonian Tropical Research Institute’s Bocas del Toro facility. The average during the previous 10 weeks was around 30 C (86 F), with normal temperatures being 28 C (82.4), the researchers said. The warming event is affecting the entire coast of Panamá, from Kuna-Yala, Isla Grande, Portobello and Galeta, to Bocas del Toro, they added.

Presumably it extends into the waters of Costa Rica. Bocas del Toro is just south of the Costa Rican border on the Caribbean.

The institute’s coral reef monitoring network, implemented over a decade ago, confirmed that temperatures started to rise in deep waters in mid-September. This network covers 33 sites on the Isthmus, with 11 sites in Bocas del Toro. The specialists confirmed that through Oct. 4 90 percent of the Bocas floor had been checked, and that mortality was limited to the Isla Colon area and further inside Bahia Almirante. This is a very vulnerable area since water circulation is slow and temperatures tend to rise easily, maintaining elevated temperatures for days and weeks, the institute said. Researchers expect to have a complete report of the state of the coral reefs in Bocas del Toro shortly.

Bleaching is the result of stress experienced by reef corals due to factors like increased water temperature, and does not necessarily mean mortality. Generally, it affects and impairs some vital activities of the organisms cycle like reproduction and growth. However, when warming is prolonged, corals start to die.

During this process, coral reefs release great amounts of mucous turning the waters turbid and bacteria and fungus proliferation is expected. Oxygen runs low and anoxic conditions may affect fish.

Panama´s authority for aquatic resources has been monitoring the water at different depths with Smithsonian personnel.

There was a similar event in 2005 in the wider Caribbean, including intense bleaching in Panama.

However, the mortality was less that 12 percent in the zone and reefs have been relatively healthy.

In the opinion of researchers, it is possible that the hurricane season is enhancing the problem and creating low water circulation in the southwestern Caribbean, thus creating a warming pocket in Panama and off Costa Rica in the sea’s western corner.

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