An underwater clash of spears: Public engagement in Mediterranean lionfish control efforts

Invasive alien species pose a great challenge in conservation ecology. Rapid establishment of common lionfish (Pterois miles) in the eastern Mediterranean Sea and its ongoing westward expansion raises many questions about how to sustainably combat this invasion in the long term. Drawing on experiences from the western Atlantic invasion, citizen scientists were engaged and demonstrated the efficiency of long-term coordinated removals for the first time in the Mediterranean Sea. Findings reveal a sustained participation and interest throughout the coordinated removal events that encourage the organization of future events. Removal Action Teams were found effective at reducing lionfish numbers in small (less than half a hectare) areas of high conservation value, when removals were repeated systematically. Single-day lionfish derbies, operated at greater spatial scales, succeeded in a 50% reduction in lionfish abundance while removing most large (>30 cm) individuals from an area after three consecutive events. Given the recreational character of such activities, coordinated removals are useful options for management and conservation when guided by competent authorities and supported by citizens, as they promote marine environmental awareness and help develop a sense of stewardship among members of the public.