First off, thanks for all showing up, and giving me a nice, big audience to talk to. When I heard I was allowed to talk to you about anything I wanted, I immediately thought of the lionfish. This is an animal that I love, and I’m very excited to share this with you.
By show of hands, who has seen a lionfish? Lucky few! Well, other than AQWA, this is where you’re most likely to find them.
This map shows the natural range of the Pterois Miles in blue, and the Pterois Volitans in green. The Indo-Pacific region has several other species of lionfish, but for the purpose of this talk, we will focus on these two. This is because of the nature of this red patch in the North Atlantic. These two species have been brought by humans to aquariums in Florida, and through carelessness were released into the ocean, and have spread like wildfire. You may have heard that the fish were released during a hurricane, and you may even have heard it was hurricane Andrew in 1992, but this is false. A genetic study of the lionfish present today indicates that they originated from 6-8 lionfish released in 1985 after they outgrew their aquarium tanks. They have since spread to the area in red, and are predicted to expand into the crosshatched area, and reach the same Southward latitude as their Pacific range. There is currently concern that they will gain access to the West coast of the US through the Panama Canal.
Above: By Alexander Vasenin – Own work, CC BY-SA 3.0
This is a major issue because of the effect they are having on their new environment. They have no natural predators in the area, and their population has exploded. A female is capable of laying 2 million eggs per year, and spawn every 3-4 days while well fed. They have been observed predating more than 40 fish species, as well as crustaceans and molluscs. They are capable of eating 20 every half hour, and up to hundreds per day. Studies in the Bahamas recorded a 65-95% reduction in the biomass of prey fish species identified in the studies. Pressure is also put on other predatory species as they are forced to compete for food.
This environmental destruction really highlights the key issue here. Introducing a foreign species is an inherently risky action and has the potential for dire consequences. Florida knows this better than most, with several introduced species outcompeting their native fauna. Boars and Burmese pythons have spread throughout the state. The risk of introducing a non-indigenous species in an environment merits a response from all levels, and this has been seen with the lionfish. If you imagine your response to an infestation of snails in your garden, you can understand the reaction of the local people in combatting the spread of the lionfish.
Currently, the most effective method of lionfish removal is spearfishing. In Florida, the population has been reduced by over 50 000 by spearfishing tournaments, and additional private fishing has put a significant dent in the population. Deepwater traps are also being developed by the University of Florida, aiming to remove lionfish from areas too deep to be cleared by scuba divers.
This response has been matched by the state government, which has tightened import restrictions in the wake of the infestation. Any foreign species may only be imported by license holders predating 2010. Additionally, after September 2018, additional species deemed a competitive risk for native fauna have been banned outright, including the yellow python, bush-tailed possum, mongoose, and many others. The Mexican government is in the process of loosening deep-water trapping regulation. Previously banned, the end goal is to allow the maximum trapping of invasive lionfish. Progress is slow however, as a reduction in by-catch has to be achieved and enforced before the trapping is environmentally beneficial.
And now onto what I believe to be the best solution to the problem, and coincidentally a misconception people hold about the lionfish. They are, without denial, an intimidating looking animal, and the fear of getting stung adds to their reputation as a fish to be feared and avoided. However, they can be fished for safely, and due to their slow movement have very soft flesh, ideal for consumption. Restaurants are being encouraged to sell the fish and create demand in the general public. As the demand rises, commercial fisheries become a viable option which has the potential to seriously affect the lionfish population. Questions have been raised about the financial feasibility of a fishery explicitly aiming to eradicate the target species, but the hope is that pre-existing fishery structures can incorporate lionfish in their target species. There is already an example being set in nature, with some grouper observed eating the lionfish. A research team caught 5 groupers, and found lionfish in the stomachs of 2, indicating that the species is predated to some extent.
Ultimately, the eradication of the species is unlikely due to how rapidly they breed, but there is hope that their impact on the environment can be minimised. This can only be achieved with a continuous effort from all involved to do their part to destroy them.
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