The lionfish, Pterois miles, is one of the most recent Lessepsian immigrants into the Mediterranean Sea, and it poses a serious threat to marine ecosystems in the region. This study assesses the basic biology and ecology of lionfish in the Mediterranean, examining morphometrics, reproduction and diet as well as population structure and distribution. The population density of lionfish has increased dramatically in Cyprus since the first sighting in late 2012; by 2018 aggregations of up to 70 lionfish were found on rocky grounds with complex reefs and artificial reefs in depths of 0-50 m. Lionfish in Cyprus become mature within a year, and adults are capable of spawning year-round, with peak spawning in summer when the sea-surface temperature reaches 28.4 C. The Cypriot lionfish grow faster and bigger than in their native range, and females are more common than males. Lionfish are generalist predators in these waters, as also found in their native range, consuming a range of teleost and crustacean prey, some of which are of high economic value (e.g., Spicara smaris and Sparisoma cretense) or have an important role in local trophic webs (e.g., Chromis chromis). Overall, the reproductive patterns, the presence of juveniles and adults throughout the year, the rapid growth rates and the generalist diet indicate that lionfish are thriving and are now already well established in the region and could potentially become the serious nuisance that they are in their temperate and tropical western Atlantic-invasive range.

The impact of recreational fishing on fish stocks remains largely unknown, as this is inherently difficult to monitor, especially in areas such as the Mediterranean Sea where many species are targeted using a variety of fishing gears and techniques. This study attempts to complement existing data sets and construct the profile of recreational fisheries in the EU‐Mediterranean countries using videos publicly available on social media. A total of 1526 video records were selected, featuring the capture of 7799 fish specimens. The results show recreational fishing is multispecies in nature (26 species contributed to >80% % of the most numerically important species caught) and exhibits a spatially homogeneous pattern, with differences in species composition being mostly dependent on the fishing technique used rather than on the country. Such findings fill an important knowledge gap on recreational fishing activities, and the methodology provides an innovative approach to gather statistics on data‐poor thematic areas that can potentially complement other data sets, such as the EU Data Collection Multi‐Annual Programme.

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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.