May 21, 2009—Voracious sea urchins are stripping coral reefs off Australia, depriving fish of key habitat, scientists say. The potential solution? Strategic deployment of urchin-eating lobsters.

© 2009 National Geographic (AP)

Unedited Transcript

The long spined sea urchin has invaded waters south of its normal range, and is now busily stripping underwater reefs of seaweed and algae.

According to scientists from Australias University of Tasmania, the sea urchin is destroying the habitats of many fish around Tasmania, including lobsters and abalone.

But while the urchins hunger after their homes, rock lobsters have developed a taste for the urchins themselves.

Ecologists are dropping large rock lobsters into the ocean to feast on the urchin.

About 750 lobsters were released in urchin-infested waters at St. Helen's off Tasmania's north east coast a year ago.

This initial project was a success.

SOUNDBITE (English) Scott Ling, University of Tasmania: "And we've surveyed that area several times and we're finding those large lobsters released - about half of those, there's evidence that they've been eating the sea urchin, so that's a good sign at this stage."

Now more are being released into waters under threat.

In Tasmanias south-east, where the latest drops are occurring, the hope is that the large lobsters will prevent the sea urchins from gaining a foothold.

SOUNDBITE (English) Scott Ling, University of Tasmania: "The work up at St. Helens, where we have large barrens, we're really looking at a cure up there. Here the urchins just appeared, and we're looking at how good these large lobsters can be at preventing the sea urchin barrens forming further."

The lobsters are tagged and dyed, encouraging fishermen not to take them out of the water. Local fishermen are supporting the project.

SOUNDBITE (English) Eddie Freeman, Lobster Fisherman: "To help out the industry, the cray industry. Just give a bit of your time, here and there, yeah we think it's very important."

Scientists will examine the lobster's waste over the next six months to ensure they're taking the bait.

In two years time they'll make an assessment of how the lobsters have fared in their battle against the urchins.