Effectiveness of Lionfish Removal Derbies Assessed in New Scientific Paper

Can members of the public help protect our environment from invasive species?
RELEASE DATE
01/10/2018
CONTACT
Ashley Yarbrough, ashley@REEF.org 305-852-0030

New research led by scientists from Reef Environmental Education Foundation (REEF) shows for the first time that volunteers are successfully defending local marine habitats against a global invader. The study, published in Conservation Letters this month, examines volunteers participating in annual fishing ‘derbies’ for invasive Indo-Pacific lionfish in the Tropical Western Atlantic, an exotic predator which consumes a range of native species and now occupies millions of square miles of marine habitat. From 2012 to 2014, the team, led by REEF affiliate scientist Dr. Stephanie Green of Stanford University’s Center for Ocean Solutions, found that derbies reduced lionfish numbers by 52% over a 192 km^2  area on average during these single-day events each year.  

To measure the effect of the volunteers’ fishing for lionfish—done primarily with nets and spears while snorkeling or scuba diving—REEF scientists surveyed lionfish and native fish species in marine environments off South Florida and in the Bahamas before and after each event. They also worked with derby organizers to document where participants fished, and the numbers and sizes of lionfish they captured. Running the data through an ecological model, the team found that before the derbies in 2012 lionfish were above levels likely to impact the native fish species they eat. However, all of the derbies they studied reduced densities of the spiny invader below levels predicted to be harmful. Areas outside the reach of volunteers continued to harbor higher number of lionfish. 

The scientists found that lionfish numbers rebounded quickly after all of the derbies, likely from nearby populations that are not culled in the derbies—meaning that removal must continue in the long term to keep invasion levels low. How often do derbies need to happen? It depends, says Dr. Green.  “In the Florida Keys, we saw lionfish getting bigger over time as the invasion progressed. Bigger lionfish have a larger impact on their prey base, and so more of them need to be removed. In South Florida, and other regions with similar conditions, derbies could be combined with other types of removal or held more than once a year to keep the invasion in check. ” In contrast, lionfish sizes and numbers decreased over the study in the Bahamas, meaning that a single day event had a bigger impact from year to year.

Co-author Lad Akins, REEF’s Director of Special Projects, emphasized that derbies are just one tool that managers have in their tool box for addressing invasions like the lionfish. Providing incentives for removal is key”, said Akins. “Lionfish is a tasty, green, alternative seafood choice and many restaurants and retailers, including Whole Foods, now offer it.” 

Derbies and tournaments for exotic species have become an increasingly popular way to educate the public about invasive species, and gather specimens for research.  REEF organized the first lionfish derby in 2009, and similar events are now held across the Gulf of Mexico, Caribbean, and Western Atlantic.  This study indicates that continuing such events makes a positive impact on the health of our coral reefs and fisheries.

About REEF: REEF conserves marine environments worldwide. Our mission is to protect biodiversity and ocean life by actively engaging and inspiring the public through citizen science, education, and partnerships with the scientific community. 

To read the full article, follow this link: http://onlinelibrary.wiley.com/doi/10.1111/conl.12426/full

Elizabeth Underwood, REEF scientist and graduate student at the University of Charleston, surveys invasive lionfish in South Florida. Lionfish occupy virtually all types of coastal habitats found in the tropical Western Atlantic.Elizabeth Underwood, REEF scientist and graduate student at the University of Charleston, surveys invasive lionfish in South Florida. Lionfish occupy virtually all types of coastal habitats found in the tropical Western Atlantic.

Volunteer Jen Russell holds an invasive lionfish captured during a lionfish derby in South Florida.Volunteer Jen Russell holds an invasive lionfish captured during a lionfish derby in South Florida.

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