‘Godzilla’ fish invade the Caribbean

Predatory fish, escaped from aquariums, are spreading 'like locusts' across Caribbean coral reefs. These alien intruders are devastating native species. Can they be stopped? And should they be?

Half a metre long, covered in spikes and tentacles, Pacific lionfish are bizarre looking creatures. They float, silently, on the vast elaborate faces of coral reefs, which plunge into the deep ocean.

To smaller fish, they look like overgrown weeds, or colourful corals. But those which approach too close find themselves caught in a deadly ambush – with perfect poise, and lightning speed, the lionfish strike, gobble up their prey, and disappear.

In their native waters, on the great reefs of Australia and the South Pacific, lionfish are only small time players. But in 1992, a freak storm destroyed a tropical aquarium, washing six lionfish into the Atlantic, thousands of miles from their home.

In these unfamiliar waters, the lionfish arrived like a tribe of 'Godzillas', as one marine biologist put it. Small fish haven't learnt to avoid them – sometimes they practically swim straight into their mouths.

And the big fish can't eat them. Lionfish are covered in deadly spines, coated in poison which causes terrible pain if it gets inside a wound. Even lionfish eggs have evolved to taste disgusting.

A female can lay 30,000 of these eggs within four days. In 2008 a single lionfish was spotted off the coast of Little Cayman, in the Caribbean. Now there are thousands of them, and they're eating their way through anything they can fit in their mouths.

Scientists fear that populations of smaller fish may have dropped by as much as 80%.

Humans are fighting back. At restaurants across the Caribbean, the deadly fish is the latest delicacy on the menu. Special competitions reward fishermen who can kill the most. And even the most fearsome array of spikes proves no defence against a speargun.

But however many lionfish divers kill, the numbers keep growing. 'I'm worried that these fish are taking over,' says Peter Hillenbrand, who's been diving the reefs for 30 years.

Tooth and claw
Is this another story of humans wrecking a fragile ecosystem? Nature exists in a delicate balance. Creatures like the lionfish, introduced by human carelessness, wreck that balance and cause terrible destruction. Sometimes whole species are driven to extinction.

But while we love nature, we often forget that it can be cruel. The history of life on earth is a story of repeated mass extinctions. Dinosaurs, mammoths, even Neanderthals – the cousins of modern humans – have all disappeared from the earth.

The animals that remain are descended from nature's survivors, tough species like the lionfish. We may not like it, but perhaps what's happening in the Caribbean is simply nature doing its bloody and ruthless work.

You Decide

  1. Humans are an invasive species which has caused and is causing mass extinctions. Does that make us as bad as lionfish?
  2. Why does it matter how many different species exist on the planet? If animals can't survive without help, why do they deserve to exist at all?

Activities

  1. Should humans intervene to control the numbers of lionfish or should we let nature take its course? Prepare the arguments for one side or another and then make your case to your class.
  2. It's not the first time humans have introduced foreign creatures to ecosystems, with dire consequences. Investigate one other example – from cane-toads in Australia to grey squirrels in the UK – and describe what happened and why.

Some People Say...

“Nature is cruel, not beautiful.”

What do you think?

Q & A

What exactly is an 'ecosystem'?
An ecosystem is the complex network of living things that all depend on each other within a particular environment. The ecosystems of Carribean reefs are particularly rich and diverse, with thousands of different species.
And why are lionfish doing so well?
Ecosystems evolve together. Some animals develop special defences, like lionfish spines, but then predators develop ways round those defences. It's like a constant natural arms race where all the different species stay in balance with each other.
So?
When animals are introduced from outside the ecosystem, like lionfish, predators haven't had the chance to catch up, and prey animals haven't learnt to escape. It's as if aliens landed on earth with advanced technology – it would take humans time to adapt, and by then we might have been wiped out.

Subjects

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