Lionfish-killing contests help control them, study claims
FORT LAUDERDALE, Fla. — They are festive killing sprees, contests among divers armed with spears and nets to catch the biggest haul of venomous, non-native fish that have colonized South Florida’s reefs.
Lionfish derbies take aim at spiky, elaborately decorated fish from the Indian and Pacific oceans that have done to Florida’s coastal waters what Burmese pythons have done to the Everglades. The fish devour native species and compete with them for prey, while reproducing at a rate that has frustrated attempts at controlling them.
The derbies, organized by environmental groups and scuba organizations across South Florida, award cash prizes for the most fish caught, the biggest fish and even the smallest fish, in a party atmosphere that often includes cooking demonstrations, lionfish tastings and live music. Some scientists have been skeptical of the effectiveness of these efforts, regarding the derbies as feelgood events that do little to hold down lionfish populations. A new study, however, claims these lionfish-killing contests can — sometimes — have lasting effect.
The study, published in the peer-reviewed journal Conservation Letters, claims that lionfish derbies reduced the species’ numbers by 52 percent over an average area of 74 square miles over three years in Key Largo and the Bahamas. The study was led by Stephanie Greene, a scientist at Stanford University’s Center for Ocean Solutions, who has worked with Reef Environmental Education Foundation, or REEF, a Key Largo nonprofit that organizes lionfish derbies.
The most successful derbies took place in the Bahamas study area, where the one-day events resulted in a permanent decrease in lionfish populations below the level that would harm native fish. Less successful was the one in Key Largo. Although numbers went down and stayed down, the lionfish that did take their place were bigger, resulting in no reduction in the threat to native fish.
Lad Akins, director of special projects for REEF and a co-author of the study, said the greater success in the Bahamas may stem from the study’s region’s isolation from other coastal waters, which would have reduced recruitment of lionfish from other populations. But he said the study showed the derbies can reduce the lionfish threat, if held frequently enough and in the places most likely to benefit from them.