Archive for May 16th, 2011

May 16, 2011

Lionfish Roundups, Reconsidered

Don’t go taking that title too seriously. The folks who’ve been bringing you the organized lionfish roundups in the Florida Keys are continuing their events, it’s the efficacy of removing non-natives in this manner that’s up for debate.

Fisheries scientists are weighing in on the long term benefits of the targeted fishing and removal of these invasive predators. By inverting the usual fisheries models, researchers were able to ask the question: how much of a dent would targeted fishing have on lionfish populations? Is sport fishing a viable method of control?

Barbour, Frazer, Sherman, and Allen’s paper over at PloS One is a bit discouraging at first glance. Their models suggest that the population would need to be fished at 35 – 65% to result in overfishing. That’s literally thousands more fish than the few hundred the roundups have so far removed. To the tune of 150 – 300 lionfish removed per hectare in the Caribbean. That’s a lot of filets, people!

Worse, given good conditions and recruitment of young fish from breeding, when the group ran a fifty-year simulation of recovery for the species after exploitation it took just six to seven years to reach 90% of its original population size before the fishing began. That means these fish, given the life history data we currently have on them in the Bahamas, are incredibly resilient.

Using targeted fishing as a method for eradicating them from all areas of their new range is likely impossible, and even intense programs for removal at local scales will prove difficult as any let up in pressure might allow them to very quickly rebound. Future marine protected area managers for the Caribbean basin, take note. This will be one management headache you’ll likely deal with your entire careers.

So what’s the good news coming out of this study? Well, the Bahamas and the wider Caribbean certainly could use another food fish. Considering the models, they may be rather perfectly suited to providing consistent sustainable meals to people in the island countries and to wider markets. ┬áIf a fishery of some scale can be established – particularly if lionfish can be marketed to the US and to environmentally-conscious types at say.. WholeFoods – it may help economically poor and depressed regions now faltering from the loss of other fisheries currently in decline or under strict regulation.

I don’t know about you, but I can certainly get behind fried lionfish sandwiches in place of mahi mahi.

Of course if we can’t finish the job on these invasives with fishing pressure, maybe we can make more headway if we teach big native predators to eat them.