Until now, few sightings of the alien lionfish Pterois miles have been reported in the Mediterranean and it was questionable whether the species could invade this region like it has in the western Atlantic. Here, we present evidence from divers and fishermen that lionfish have recently increased in abundance and within a year colonised almost the entire south eastern coast of Cyprus, likely due to sea surface warming. At least 23 different fish are reported of which 6 were removed. Groups of lionfish exhibiting mating behaviour have been noted for the first time in the Mediterranean. Managers need this information and should alert stakeholders to the potential ecological and socio-economic impacts that may arise from a lionfish invasion. Actions could involve incentives to engage divers and fishermen in lionfish removal programmes, as these have worked well at shallow depths in the Caribbean. Given that the Suez Canal has recently been widened and deepened, measures will need to be put in place to help prevent further invasion.

The European Regulation (EU) 1143/2014 on Invasive Alien Species entered into force in 2015, with the aim to fulfill regional and international biodiversity goals in a concerted manner. To date, the Regulation listed 66 Invasive Alien Species (IAS) that are subject to legal controls. Only one of these is marine. A recent lionfish (Pterois miles) invasion has been closely monitored in the Mediterranean and a detailed risk assessment was made about the profound impacts that this invasive fish is likely to have on the fisheries and biodiversity of the region. In 2016–21, lionfish rapidly became dominant predators along Eastern Mediterranean coasts, yet the process for their inclusion on the EU IAS list has been lengthy and is ongoing. There is an urgent need to learn from this experience. Here, we recommend improvements to the Regulation 1143/2014 and the risk assessment process to protect marine ecosystems and secure the jobs of people that rely on coastal resources.

Widespread reports over the last six years confirm the establishment of lionfish (Pterois miles) populations in the eastern Mediterranean. Accumulated knowledge on lionfish invasions in the western Atlantic Ocean has shown that it is a successful invader and can have negative impacts on native species, indirect ecological repercussions and economic effects on local human societies. Here we analysed genetic sequences of lionfish from Cyprus as well as data from the whole distribution of the species, targeting the mtDNA markers cytochrome c oxidase subunit 1 (COI) and the control region (CR). Our results reflect a pattern of repeated introductions into the Mediterranean from the northern Red Sea and a secondary spread of this species west to Rhodes and Sicily. Presented results agree with previously published studies highlighting the genetic similarity with individuals from the northern Red Sea. Nevertheless, some individuals from Cyprus, in addition to those coming via the Suez Canal, were genetically similar to fish from the Indian Ocean, indicating genetic homogeneity among populations of P. miles across its current distribution, possibly facilitated by the ornamental fish trade and/or transport through ballast water.

A lack of biosecurity in the Suez Canal has combined with global warming and other human pressures to cause abrupt changes in the Mediterranean Sea. Throughout this region an influx of species is influencing the outcome of efforts to protect and restore nature. Despite calls for targeted removals of invasive species from protected areas, there is limited information about the effectiveness of this course of action from both an ecological and a socio‐economic perspective. In this study, coordinated removals of lionfish (Pterois miles) by volunteers/scuba divers at three marine protected sites in Cyprus were conducted. The removal efficiency was monitored using visual‐census surveys and citizen science data. Removals significantly decreased lionfish numbers but long‐term suppression of lionfish would require monitoring and repetition of removals when necessary, since population recovery was sometimes rapid. Citizen science yielded the data needed to understand lionfish population changes and guide the timing of removal events, but was characterized by large variation and potential outliers, highlighting the need for large sample sizes. Questionnaire surveys were used to assess the social impact of participation in lionfish removals; these showed that involvement had a strong positive impact on knowledge about lionfish and motivation to support marine conservation activities – the divers were even willing to pay extra to remove lionfish. Management reforms would be needed to capitalize on this societal motivation, and enable effective lionfish removals by scuba divers, coordinated by competent authorities. The EU aims to protect at least 30% of the marine waters by 2030. Removal events could help shield selected conservation sites from the adverse effects of lionfish and at the same time help establish links with local communities, strengthening the sustainable use of marine systems both at corporate and at societal levels.