By: Mark Hixon, Mark Albins, and Tori Redinger
Indo-Pacific lionfish are rapidly invading the waters of the Caribbean
and tropical Atlantic. Due to their population explosion and aggressive
behavior, lionfish have the potential to become the most disastrous
marine invasion in history by drastically reducing the abundance of
coral reef fishes and leaving behind a devastated ecosystem. Dr. Mark
Hixon and his team from Oregon State University with support from
NOAA’s Undersea Research Program (NURP) have embarked on the first
studies to measure the severity of the crisis posed by this invasive
The lionfish, native to the Indo-Pacific region, have infiltrated their
way into the Caribbean. Their introduction is believed to be a result
of hurricanes and tank releases during the early 1990’s. They have been
spotted along the eastern seaboard spanning as far north as Rhode
Island to as far south as Columbia. Protected by venomous spines,
lionfish are voracious and effective predators. When hunting, they herd
and corner their prey using their pectoral fins, then quickly strike
and swallow their prey whole. With few known natural predators, the
lionfish poses a major threat to coral reef ecosystems in the Caribbean
region by decreasing survival of a wide range of native reef animals
via both predation and competition. While native grouper may prey on
lionfish, they have been overfished and therefore unlikely to
significantly reduce the effects of invasive lionfish on coral reef
Lionfish found near Lee Stocking Island. Photo credit: Mark Albins, University of Oregon State
A Photograph from above of a lionfish.
Photo credit: Mark Albins, University of Oregon State
In the last several years, members of Dr. Mark Hixon’s lab working
at the NURP Caribbean Marine Research Center at Lee Stocking Island
(LSI), a field station at the southwestern end of Exuma Sound, Bahamas,
have documented increasingly frequent sightings of lionfish. These
findings have provided an unprecedented opportunity to study the
ecological interactions of lionfish with Caribbean coral reef fish
communities from the very beginning of the invasion. In the summer of
2005, they found their first lionfish near LSI. Between the fall of
2006 and summer of 2007, the lionfish population in the Bahamas
increased substantially. During the summer of 2007, over 100 lionfish
were spotted around LSI signifying a rapid expansion within the
PhD student Mark Albins of Hixon’s team devised a controlled experiment
testing the effects of lionfish on native fish communities by
documenting the recruitment of newly settled reef fishes on 20 patch
reefs near LSI: 10 reefs with a lionfish and 10 reefs without. Fish
censuses were conducted at one week intervals for five weeks.
Recruitment was significantly lower on lionfish reefs than on control
reefs at the end of the experiment. On one occasion, a lionfish was
observed consuming 20 small wrasses during a 30 minute period.
Researcher Mark Albins documenting a lionfish in the Bahamas. Photo credit: Mark Albins, University of Oregon State
Diver observing a lionfish among corals.
Photo credit: Mark Albins, University of Oregon State
It was not unusual to observe lionfish consuming prey up to
2/3 of its own length. Results of the experiment show that lionfish
significantly reduce the net recruitment of coral reef fishes by an
estimated 80%. The huge reduction in recruitment is due to predation
and may eventually result in substantial, negative ecosystem-wide
consequences. It is also important to note that lionfish have the
potential to act synergistically with other existing stressors, such as
climate change, overfishing, and pollution, making this invasion of
particular concern for the future of Atlantic coral reefs.
Stocking Island facilities Exuma, Bahamas. This island is surrounded by
extensive patch reefs, seagrass meadows, and mangrove forest.
Photo credit: Perry Institute for Marine Science
While complete eradication does not seem realistic, affected nations
are encouraged to initiate targeted lionfish control efforts as soon as
possible, including targeted fisheries (lionfish flesh is tasty and
cooking denatures the spine venom). Efforts to reduce densities of
lionfish at key locations may help to lessen their ecological impacts.
Recovering and maintaining healthy populations of potential native
predators of lionfish, such as large grouper and sharks, may also help
reduce the deleterious effects of these voracious invasive predators.
Hixon’s team will return to the Bahamas this summer and
thereafter to conduct further field experiments, field observations,
and laboratory experiments to answer important questions regarding the
invasion and how lionfish interact both directly and indirectly with
native Bahamian reef fish and invertebrate communities. They will also
work in the Pacific Ocean to understand what naturally controls
lionfish abundance in their native range.
|NOAA’s Undersea Research Program (NURP) provides scientists with the tools and expertise they need to
investigate the undersea environment, including submersibles, remotely
operated vehicles, autonomous underwater vehicles, mixed gas diving
gear, underwater laboratories and observatories, and other cutting edge
technologies. NURP provides extramural grants to both the federal and
non-federal research community through its six regional centers and the
National Institute of Undersea Science and Technology.