An explosion in the population of the predatory lionfish in Caribbean waters, where it has no natural predators, is posing a widespread threat to marine wildlife.

I have seen thousands of these fish in the Indian and Pacific Oceans, but they should not be here in the Caribbean.

No invasive tropical fish species has ever survived so successfully outside its own home ecosystem like this
Dr Carrie Manfrino

„These fish are like Godzilla,“ Peter tells me on the boat after we surface.

„Two or three years ago we would see the odd one here and there, but now on every dive they’re there.

„I’ve been diving these reefs for over 30 years and I’m worried that these fish are taking over,“ he says.

On Little Cayman, I visit the Central Caribbean Marine Institute, where scientists are studying the invasive population of lionfish, more properly known as Pterois volitans.

„Their stomach can expand up to 30 times its volume,“ Morgan explains.

„And they can swallow any other fish up to two thirds their own body length.

„But they seem to have no natural predators here in the Caribbean.“

The facts about lionfish are frightening.

A female can produce 30,000 eggs every four days. The eggs are unpalatable to other fish.

And lionfish are growing larger than they do in their native waters – up to 18in long (47cm), and they are stealthy ambush predators.

No-one knows how lionfish got into the Caribbean.

One theory says they escaped from a Florida aquarium during a hurricane about 10 years ago.

Others believe that tropical fish keepers released their pets into the sea when they grew too large to keep at home.

„One study in the Bahamas showed that lionfish reduced native species populations on one reef by almost 80%“

It does not really matter how they got here, but since 1992 they have spread from Florida up the east coast of the United States as far north as Long Island in New York.

About six years ago they crossed the western Atlantic to Bermuda and then drifted south to Bahamas, Jamaica and Cuba.

In 2008 the first lionfish was spotted at Bloody Bay on Little Cayman.

One year later there were hundreds, and now thousands. And they have now gone south as far as Venezuela.

„This isn’t just an invasion,“ explained Dr Carrie Manfrino, Research Director at the Central Caribbean Marine Institute.

„This is an explosion. No invasive tropical fish species has ever survived so successfully outside its own home ecosystem like this.“

Source: BBC 07.05.2011

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