The Strait of Sicily in the middle of the Mediterranean Sea is considered a crossroads between the western and the eastern basins for species immigrating from the Atlantic Ocean and Lessepsian species. Among the latter, the African sailfin flyingfish Parexocoetus mento was recently collected from Lampedusa Island in November 2017, and represents the first documented record in Italian waters. In this paper, the morphological and meristic characteristics of this specimen are reported and discussed, compared with the other species of the genus Parexocoetus. Furthermore, as mapping and monitoring the distribution of invasive species is crucial to understanding their establishment and spread and then to manage the invasion process, the occurrences distribution of P. mento in the Mediterranean Sea was studied. The application of GIS-based spatial statistics allowed to identify significant clustering areas and dispersion areas of the species, summarizing the key characteristics, and underlining directional trends of distribution. GIS analysis identified two similar groups of records (1935/1966 and 1986/2017 time period), showing a change of distribution spatial pattern over time. An earlier spread direction in the Mediterranean east coast and a settled area of P. mento were found. The analysis also includes the specimen caught in Italian waters.

This study is the first work on the reproductive biology of lessepsian bivalve Fulvia fragilis. Monthly and bimonthly samplings were made in the period from April 2006 to October 2007, at the Bay of Tunis (northern Tunisia). From histological preparations of gonad, a gametogenic scale was drawn up based on eight stages: sexual rest; initiation of gametogenesis; advanced gametogenesis; ripe; partial spawning; advanced spawning; restoration; and spent. After examination of gonad preparations, F. fragilis appeared to be a simultaneous hermaphrodite species. Spawning was continuous all along the year, scarce in winter and with peaks during the rest of the year. The spawning peaks were positively correlated with the rise of the sea surface temperature and the nutrient availability. Furthermore, the presence of oocytes surrounded by spermatozoa in female and male follicles and in male gonoducts was observed. Self-fertilization may occur in this species. High summer mortalities probably due to the combination of vulnerability of the bivalve in response to the reproductive effort and high temperature stress were recorded. The F. fragilis reproduction strategy explains the success of its installation on the Tunisian coast.

Between October and November 2010, several individuals of Fistularia commersonii, a lessepsian species, were fished by trammel nets in less than two weeks along the French coast in the north-western Mediterranean. These catches represent the most important records of the species in the western basin of the Mediterranean to date, specifically in areas where the species has rarely been observed before. This paper synthesizes the records of F. commersonii along the French coast starting from the first record in November 2007 until the most recent reports, and discusses the present status of the species in the north-western Mediterranean Sea.

A total of fifteen adult specimens of the so-called ‘lessepsian sprinter’ Fistularia commersonii were captured by bottom trawlers and gill-netters operating along the Latium coasts, Italy, in October–November 2007. This non-native species is established in the eastern Mediterranean but it has been sporadically reported beyond the Strait of Sicily. Never before has the species been recorded in such large numbers from a single locality in the western Mediterranean. These records may suggest an incoming establishment of a self-sustained population of the species also in the western Mediterranean and they document for the first time the presence of a lessepsian fish in Latium waters. Biometry and meristics of the available specimens of F. commersonii and data on their diet and reproductive condition are given.