This was unexpected and it is catastrophic, a true ‘Black Swan’ event.
Pacific Red Lionfish invaded the US southeast coast and the Caribbean about a decade ago, and they have now successfully invaded the rest of the Gulf of Mexico, including the coasts of Belize and Texas. They are most common on coral reefs, but they are generalists, and turn up in grass beds, mangroves and rocky caves as well, down to depths of 200 meters.
The invasion probably started from a dumped aquarium on the US south east coast sometime in the 1980s. Now it is the single best example of a successful invasion of a marine fish species. We’re accustomed to invasive marine plants and invertebrates, but fish species are rarely successful. This one is.
For a continually updated map of the invasion, check the US Geological Survey website.
With its elaborate fins, stripes and spines, this is one very beautiful fish. The tips of its spines concentrate a powerful neurotoxic venom that protects it from most predators – including any human who handles it too casually. By the time it is an adult it about 45cm (20 inches) long, able to reproduce a few times each month all year long.
It is a slow-swimming predator, eating fish up to about half its size. At the high densities it is now reaching in many communities on many reefs, prey species are declining by 90% or more. The degraded reefs of the Caribbean need an abundance of herbivores if they are ever to recover. so the invasion of lionfish is a further catastrophe in the sad litany of catastrophes that have converted so many of the reefs to algal rubble.
In the Indo-Pacific, large predatory fish like eels, sharks and groupers somehow manage to eat lionfish and help to keep their numbers under control. In the Caribbean and Gulf of Mexico we’ve fished out most large fish already, and those that remain are learning to avoid them, not how to eat them without being stunned.
No wonder it is such a successful invader – an efficient and cryptic, with a rapid growth rate and huge reproductive potential, and pretty well free of predators.
So what’s ahead? Either lionfish will become so abundant that they will eat up all the available prey, wreck the available ecosystems, and then starve – a miserable outcome to say the least.
Or we can eat them.
This is an astonishing development. Everywhere in the Caribbean, in the Gulf of Mexico and around Florida we are now encouraged to hunt them down by spear, line or trap. Fishing derbies have emerged in many places. There are no restrictions – just catch and kill as many as you can.
What about those spines and their neurotoxins? Internet videos show you how to handle the fish and clip off the spines. What’s left is free of the toxins.
So go forth and kill. As many as you can. We may never have an opportunity like this again – a chance to exploit a new fishery, free of any regulations, a last echo of the old days when all fish were superabundant and we were not.
And if you can’t go killing lionfish, ask your restaurant to include them. This is not a trivial matter – if we don’t stop them, lionfish will wreck whatever is left of the precarious reefs in the Caribbean and the Gulf of Mexico.