Safe haven for lionfish at study sites

Researchers investigating the
growing invasion of lionfish are requesting divers not to capture and kill
lionfish at two Little Cayman dive sites so they can closely study the venomous
fish throughout the summer months.

Oregon State University biologist,
Professor Mark Hixon, who has been studying how lionfish have invaded the
Caribbean, said divers are being asked not to take lionfish at Snap Shot and
Sailfin Reef on the northern coast of the island over the summer so researchers
can study their movements, survival, growth, and interactions with native
predators and competitors to compare with their counterparts in the Pacific

Mr. Hixon said by doing this,
scientists may be able to learn more about why the species has become so
prolific in the Atlantic.

“At the end of the summer, we will
collect them all for parasite studies – lionfish in the Bahamas have no
parasites, even though all native fishes do. Examining fish for parasites in
Little Cayman and the Pacific this summer will help us know whether resistance
to parasitism is one of the reasons the invasion is so successful,” he said.

Mr. Hixon visited Cayman earlier
this summer to prepare for the research project sponsored by the US National
Science Foundation. Two graduate students have remained in Little Cayman to
work on the project.

Lionfish are believed to have been
released from aquaria in Florida in the early 1990s and since then their population
has exploded, spreading from the mid-Atlantic coast of the US to southern

The venomous fish have no natural
predators in the Caribbean and a single lionfish can wipe out nearly 80 per
cent of small and juvenile fish populations on a patch of coral reef in just
five weeks. They can spawn 30,000 eggs a month.

Divers are hoping that groupers can
be taught to eat lionfish and on Little Cayman, dive masters have been feeding
dead lionfish to grouper, lobsters, tarpon and other marine life. They have
also been pointing out lionfish to large, tame Nassau Grouper on Bloody Bay
Wall and the grouper have been eating them.

Scientists are concerned that the
lionfish may severely reduce the abundance of native coral-reef fish important
as food for humans, such as grouper and snapper in their juvenile stages, as
well as species that maintain the integrity of coral reefs, like grazing parrot
fish that can prevent seaweeds from smothering corals.

Mr. Hixon and his team have been
studying the impact of the lionfish in the Bahamas, which has been hard hit by
the invasion of lionfish. Comparative studies are being done with lionfish in
their native Pacific Ocean.

Currently, the only way to cull the
lionfish population is for divers to catch them in nets.

“Culling is very effective over
small areas, but complete eradication is unlikely unless natural controls –
predators, competitors, parasites, diseases – kick-in,” said Mr. Hixon, who
spent a week in Cayman in June and plans to return next year.


Lionfish pictured on a Cayman reef.
Photo: Kristi Feierstein