The Lionfish Menace

To quote Professor Isabelle Côté, “…in its natural environment, the Lionfish is an unremarkable part of coral reef’s ecology.”. A noted tropical marine biologist, I have had the pleasure of training under her as a scientific diver and attending a lecture on the topic of the Lion Fish invasion of the caribbean and eastern coast of the United States. Outside of the indo-pacific, the Lionfish is an apex predator that local ecosystems are not geared to handle.

Lionfish is a generic term for a variety of highly venomous and voracious predatory fish, commonly found in the Indian Ocean and tropical Pacific of the genus Pterois. Some particularly lost specimens can be found in the Mediterranean Sea as well. As said before, in their natural environment, these fish are unremarkable. So much so that it wasn’t until their invasion of the Caribbean and east coast of the USA that serious effort went into researching them. Hardy and fecund, without their natural predators and the animals that eat the vast numbers of eggs they produce, they can swiftly come to dominate a reef ecosystem and destroy the biodiversity found there in.

The method of Lionfish introduction into the warm waters of the Caribbean and eastern coast of the USA is a debated topic. The most likely causes are intentional release of the fish by aquarium owners, and the results of Hurricane Andrew, where six were accidentally released and others may have been freed by the destruction of an aquarium in Florida. Regardless, the small number that reached the wilds have in turn become a self perpetuating disaster for the area. As mentioned before, the Lionfish s fecund, and produces vast numbers of eggs that have few of the predators that would keep their numbers controlled in their home waters. This has lead to a population explosion that has slowly by inexorably worked its way down the island chains of the Caribbean and inched along the coastal areas in Gulf of Mexico. They have also spread north, following the warm waters up the eastern coast of the USA.

To battle Lionfish, many ideas have been put forward, but the most popular with divers (and cooks) is the active hunting of Lionfish. In a true indication of their numbers and threat, Lionfish are an “unlimited catch” fish, where you can catch/kill as many as you want or can. Various recipes have even sprung up for them, as well as a new PADI Specialty, and they are apparently quite tasty. Unfortunately, this is only a stop gap measure, as they can only be caught by spearing them, and there just aren’t enough divers. Other control methods have included teaching indigenous sharks to eat them and efforts have been made to reintroduce groupers to Caribbean reefs as a natural control measure.

The introduction of alien species to a new environment seldom goes well, whether its an intentional introduction (Bluestripe Snapper in Hawai’i), or mostly accidental (Lionfish). A common thought is often “mother nature will balance”; this just isn’t true for the most part, especially with prolific species that can out compete all of their potential competition and that has a hunter style that their prey simply cannot or don’t have time to adapt to. Most areas of the world have invasive species now, and there are usually BOLO’s (be on look out) available for your diving area. If you see something that doesn’t belong, or that is listed on a Parks or Fisheries BOLO, pass it on as soon as you can!

For more information on Lionfish and what’s being done about them, check out the following links:

Special thanks to Isabelle Côté, for her great lecture that got me looking into this topic. Isabelle Côté is a Professor at Simon Fraser University, where she is head of the Tropical Marine Biology Lab

About the author

Graeme Barber is a professional diver, qualified as a PADI and SDI Divemaster, DCBC 40m Unrestricted Commercial Scuba Diver, 30m Restricted Surface Supply diver, and CAUS Scientific Diver Lv.2. In addition to being the head of Cold Water Diver, he's a full time student working on a degree in Archaeology.