Grouper controls invasion of lionfish on coral reefs

Grouper may be able to limit the invasion of lionfish on Caribbean coral reefs, reports a study published this week in the online journal PLoS One. Lionfish, which are not found naturally in the Caribbean, are believed to have been released from aquariums in the United States and eventually made their way to the Bahamas in 2004. Lionfish numbers have increased dramatically in the last few years and they have now invaded the entire Caribbean.

Although lionfish are among the most beautiful fish in the sea, they are voracious predators of small fish and conservationists are concerned about their impact on native fish populations.

A research team from the University of Queensland (Australia) and American Museum of Natural History (New York) studied the invasion of lionfish in a remote stretch of coral reef in the Bahamas. The reports lead author, Professor Peter Mumby, states, “In 2006 we did not encounter any lionfish but by 2010 they were at all of our 12 study sites. However, the number of lionfish was ten times lower in reefs with lots of large groupers”.

The team surveyed reefs inside and outside the Exuma Cays Land and Sea Park, which is one of the best marine reserves in the Caribbean, having been established in 1959. Prof Mumby continues, “With long-term protection from fishing, grouper numbers are among the highest in the Caribbean and we believe that groupers are eating enough lionfish to limit their invasion on these reefs”.

This news is positive for conservation efforts but Mumby adds a cautionary note, “Years of over-fishing means that densities of large grouper, like the Nassau grouper, are low throughout most of the Caribbean. If we want grouper to help us control the lionfish invasion we’ll have to develop a taste for lionfish instead of grouper and drastically reduce the fishing of this species”.