The red lionfish (Pterois volitans), popular among many aquarium enthusiasts, is a large fish native to the indo-Pacific region of the Pacific ocean. It has few predators and is able to survive in a variety of conditions, making it a formidable invasive species. Originally introduced into the Atlantic Ocean along the coast of North America, it has since damaged Bahamian ecosystems and reef systems.
Red lionfish populations in the Bahamas have been observed to be at a density of 390 lionfish/hectare, a density high than recorded even in their native habitats. Its high rate of population growth is due to a lack of any predatory fish in the Atlantic Ocean. A lack of competition has enabled these invaders to decrease Atlantic fish recruitment in the Bahamas to coral reefs by 79%.
Rui Dai of Duke University, among numerous other researchers, postulates that not all hope is lost for the Bahamian coral reefs. In 2008, several Nassau and tiger grouper (native Bahamian grouper species) were found to have lionfish remains in their stomachs. Dai is interested in whether these Bahamian grouper, perhaps with the help of humans, may be able to serve as natural biocontrol for the red lionfish.
To test her theory, Dai plans to place several groups of different proportions of the grouper, the lionfish, and other fish species native to the Bahamas in commercial fish pens, which are used while still in the ocean. This type of fish pen will be used because it should enable salinity levels, etc., in the experiment to be identical to those in the Bahamas, the environment in which the results of this study are applicable.
Each test group will contain one Bahamian grouper (of either species) and two, four, or eight lionfish, as well as a variety of crustaceans, small fish, and squid found in the Bahamas. Dai will also test the grouper at different ages (five months old, one year old, and five years old) to see whether only the largest adult grouper could be successful biocontrol agents. Each morning, Dai plans to observe which species are still present in each pen. The entire study will last approximately three months, after which point Dai expects to have enough data to draw conclusions about the approximate success of Bahamian groupers as biocontrol agents against red lionfish.
Dai expects that large numbers of the adult grouper will be the most successful biocontrol agents, though human assistance will be imperative for their success. Once Dai has obtained results from her study, she hopes that others will continue research about how to best implement Bahamian grouper as biocontrol agents against the red lionfish.