San José, Costa Rica, since 1956

El Niño a Mixed Blessing for Divers on Pacific

The weather phenomenon known as El Niño, or “The Child”, affects all of Earth’s atmosphere and waters, from the highland Himalayas in Tibet and China to currents running over Costa Rica’s dive sites.

An El Niño becomes official when the eastern tropical Pacific warms up to higher than usual temperatures while the western tropical Pacific cools a bit compared to normal. Ancient Peruvians first named the warming of their coastal waters El Niño because they noted that it happened around the time of the birth of the Christ child, El Niño, or Baby Jesus.

Costa Rica’s Pacific is part of the eastern tropical Pacific, and that means El Niño brings a warming of our waters as well.

Anyone who has dropped into Costa Rica’s Pacific waters in the past few months knows that the ocean’s temperature has been about that of a warm bath. The last time it was this warm was during the last strong El Niño in 1997-98, when the warm water stretched from Peru to Canada. This time it made it only to Mexico, and so the experts have deemed this event a moderate one. That’s good news for most of Costa Rica, but it’s a mixed blessing for divers.

El Niño not only means warm water at dive sites from Santa Rosa National Park in the northwestern province of Guanacaste to Cocos Island, hundreds of kilometers southwest of mainland Costa Rica, but also the waters turn clear.

During January and February, visibility topped 50 meters on some days at Caño Island Biological Reserve, 20 kilometers off DrakeBay on the OsaPeninsula, on the southern Pacific coast. The waters were so clear that it seemed that divers were suspended in air. The transparency revealed the topography of the bottom like few times before.

Many dive sites normally require navigation underwater to see different areas of interest. When you are underwater and the water is not so clear, to reach a distant rock or coral outcropping, you must navigate using a compass, or the sun’s rays falling at an angle, or you might just see nothing but sand. This is when guides become very useful for divers.

But during the past couple of months, the water has been so clear that no navigation has been required. When you can see them, distant rocks are about as hard to find as the other side of a swimming pool.

Most of us guides used this visibility to extend our knowledge of the area surrounding dive sites. It’s a special thrill to see new parts of a site you have known for many years.

The clear water is nice, but the warm El Niño waters also mean fewer fish for Costa Rica’s Pacific. A great deal of marine life prefers cooler waters. This season’s humpback whales seemed to arrive late, were few in number, and were generally scarce during January, normally a peak month.

A few corals at CañoIsland began to turn white, or bleach, as a result of high temperatures – not a good thing.

Then, over the past few weeks, the cool, green water that El Niño usually holds down below 30 meters began to rise up toward the surface. A strong current began blowing the cool water from the southwest over the dive sites. Mirror-flat seas were replaced with a small swell that stirred things further. Corals at Caño grew their colors again, and fish started showing up in massive numbers.

Rains fell on the parched forests of the southwest Pacific coast. Rains let up on the southern Caribbean coast, and the sea calmed down. El Niño is over, and not a moment too soon.

Both coasts were reporting good diving at press time. As usual, now is the time to go diving in Costa Rica.


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