In recent years, there has been a decline in coral reef fish population on the East Coast of the United States and in the Caribbean Sea as a result of the accidental introduction of the lionfish, a predatory species, native to the South Pacific and the Indian Ocean. Marine ecologists have developed various methods to decrease the impact of lionfish on local fish communities. Despite the efforts, it is unlikely this predatory species will be removed completely from its host ecosystem because it is fast-reproducing, every 3 or 4 days, laying up to two million eggs each year. Lionfish are capable of destroying 90% of a coral reef, displaying aggressive tendencies and forcing native species to move to less suitable habitats.
Causal factors and geographic location:
The decline in native coral reef fishes and crustaceans has been linked directly to a growing population of lionfish. This predatory species competes for food with local piscivores and destroys the coral reef diversity. It could also impact the population of herbivorous fishes, such as parrotfish, that consume macroalgae from overgrowing corals. It has been speculated that the lionfish were released into the wild by aquarium enthusiasts as early as 1990, which is when it was first noticed outside its native waters. Currently it inhabits most of the Caribbean Sea, the Bahamas, the East Coast of the United States. Recently, lionfish specimens have also been found in the Panama Canal.
The species description and the IUCN status:
Pterois volitans, Scorpaenidae family, Actinopterygii class, is a spiny venomous marine fish native to the Indo-Pacific region. However, in recent years it has become invasive along the east coast of the United States and in the Caribbean Sea, together with a closely related fish, Pterois miles, which is not as abundant. Pterois volitans, is commonly referred to as the red lionfish, zebrafish or the butterfly cod and, according to IUCN, it is not currently listed as threatened or endangered. Lionfish are characterised by alternating white and reddish-brown vertical stripes and by the presence of 13 dorsal venomous spines and they have a diet based on the consumption of coral reef fish, mollusks and crustaceans. The parrotfish, which is currently of least concern according to IUCN, is increasingly endangered by the presence of lionfish populations in the coral reefs and so are the juveniles of the commercially important spiny lobster, Panulirus argus. Conservationists have tried to decrease the lionfish biomass in the Atlantic and the Caribbean Sea by teaching native sharks that this quite recently introduced species is edible. Some have criticised this practice because it may alter the balance of the ecosystem and lead to unforseen consequences. However, people are also encouraged to consume it.
A scientific study on the Atlantic coral reef fish conservation issue :
Green, S., Akins, J., Maljkovic, A., Côté, I.: “Invasive Lionfish Drive Atlantic Coral Reef Fish Declines” (2012). This study was conducted on nine coral reef areas off New Providence Island in the Bahamas. Over a period of three years, its purpose was to determine the impact that the lionfish’s predatory behaviour had on native reef fish communities. The results of the paper indicated that 90% of the prey ingested by lionfish belonged to 42 species of small-bodied coral reef fishes. The biomass of these native fish communities rapidly declined by 65% between 2008 and 2010, indicating a negative long-term impact on the structure of the Atlantic marine communities and on the economies that depend on them. Also, the study speculated that in time, populations of large-bodied fishes will be affected by lionfish if consumed as juveniles.