The Presence of the invasive Lionfish Pterois miles in the Mediterranean Sea

Here we report the occurrence of Pterois miles in the Mediterranean Sea, based on the capture of two specimens along the coast of Lebanon. Previously, only one record of the species from the Mediterranean Sea had been documented. The new records highlight the arrival of new propagules of P. miles, more than two decades later, hinting to a future potential invasion of the Mediterranean Sea

First sighting of Zebrasoma flavescens (Teleostei: Acanthuridae) and Balistoides conspicillum (Teleostei: Balistidae) in the Mediterranean Sea: Two likely aquarium releases

Here we provide the first documented occurrence of the yellow tang Zebrasoma flavescens and of the clown triggerfish Balistoides conspicillum in the Mediterranean Sea. These tropical fishes were photographed in October 2008 off Sitges (Costa Daurada, Spain: 41°13'27.09" N; 1°47'22.35" E) and in July 2012 in front of Palamós (Costa Brava, Spain: 41°50'56.19" N; 3°8'26.29" E), respectively. Their possible release from private aquaria is discussed

Fish diversity associated with gas platforms: Evaluation of two underwater visual census techniques

Fish assemblages associated with offshore platforms were surveyed using two underwater visual census techniques: strip transects and mobile point counts. Data were collected from four depth ranges at three platforms off Crotone, Italy (Ionian Sea). A total of 25 fish species belonging to 12 families were recorded for the three platforms. Significant differences between sampling methods and depth were observed in the fish assemblage structure, species richness and fish abundance. The mean number of species recorded with the strip transect method was always greater than that obtained with mobile point counts, whilst the opposite pattern was observed for mean abundances. Gregarious species such as Boops boops, Chromis chromis, Anthias anthias and Oblada melanura were responsible for most of the differences in the assemblage structure. According to our results, both methods allowed us to observe species that are not usually caught by means of fishing gear. When both census techniques are used, they provide complementary information about the fish assemblages strictly associated with the platform structures

First record of the twobar sea bream Acanthopagrus bifasciatus (Teleostei: Sparidae) in the Mediterranean Sea

In September 2010, one specimen of the twobar seabream Acanthopagrus bifasciatus was recorded for the first time in the Mediterranean Sea, off the Islands of Zembra (Gulf of Tunisi: 37°07’03’’N; 10°48’35’’E). This species could have entered the Mediterranean via the Suez Canal or alternatively by unintentional human transport

Tracking the invasion of Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts: A Local Ecological Knowledge study

Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investigate on the occurrence and establishment of the exotic Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts. According to fisherman’s knowledge, H. far and S. undosquamis appeared in Libya, in 1980 and 1989 respectively. In Tunisia these species were observed afterwards, in 2004 and 2007. Currently both H. far and S. undosquamis result to be well distributed and established, along the entire surveyed area, from Tubrouk (eastern Libya) to Tabarka (western Tunisia). A statistical analysis of the qualitative trends in abundance perceived by the respondents show that both species have significantly increased in abundance in Tunisia. In Libya an increase of the abundance of H. far was also apparent during the first decade of the 21st century but the current abundance of S. undosquamis resulted to be stable at the level of occasional captures. Given the lack of regular environmental monitoring programmes in the area, these findings provide information that could not have been obtained otherwise. Besides improving our understanding on the status and chronology of these invasions, this approach highlights the value of fisherman’s knowledge to reconstruct ecological process in the course of rapid historical modifications

Marine alien species in Italy: A contribution to the implementation of descriptor D2 of the Marine Strategy Framework Directive

A re-examination of marine alien species or Non Indigenous Species (NIS) reported in Italian Seas, until December 2018, is provided, focusing on establishment success, year of first record, origin, potential invasiveness, and likely pathways, in particular. Furthermore, their distribution is assessed according to the marine subregions outlined by the European Union (EU) Marine Strategy Framework Directive: Adriatic Sea (ADRIA), Ionian Sea and Central Mediterranean Sea (CMED), and Western Mediterranean Sea (WMED). In Italy, 265 NIS have been detected with the highest number of species being recorded in the CMED (154 species) and the WMED (151 species) subregions, followed by the ADRIA (143) subregion. Most of these species were recorded in more than one subregion. One hundred and eighty (180 or 68%) NIS have established stable populations in Italian Seas among which 26 have exhibited invasive traits. As regards the taxa involved, Macrophyta rank first with 65 taxa. Fifty-five of them are established in at least one subregion, mostly in the ADRIA and the CMED. Crustacea rank second with 48 taxa, followed by Polychaeta with 43 taxa, Mollusca with 29 taxa, and Fishes with 28 taxa, which were mainly reported from the CMED. In the period 2012-2017, 44 new alien species were recorded, resulting in approximately one new entry every two months. Approximately half of the NIS (~52%) recorded in Italy have most likely arrived through the transport-stowaway pathway related to shipping traffic (~28% as biofoulers, ~22% in ballast waters, and ~2% as hitchhikers). The second most common pathway is the unaided movement with currents (~19%), followed by the transport-contaminant on farmed shellfishes pathway (~18%). "Unaided" is the most common pathway for alien Fishes, especially in the CMED; escapes from confinement account for ~3% and release in nature for ~2%. The present NIS distribution hotspots for new introductions were defined at the first recipient area/location in Italy. In the ADRIA, the hotspot, Venice, accounts for the highest number of alien taxa introduced in Italy, with 50 newly recorded taxa. In the CMED subregion, the hotspots of introduction are the Taranto and Catania Gulfs, hosting 21 first records each. The Strait of Sicily represents a crossroad between alien taxa from the Atlantic Ocean and the Indo-Pacific area. In the WMED, bioinvasion hotspots include the Gulfs of Naples, Genoa and Livorno. This review can serve as an updated baseline for future coordination and harmonization of monitoring initiatives under international, EU and regional policies, for the compilation of new data from established monitoring programs, and for rapid assessment surveys

Tracking Signals of Change in Mediterranean Fish Diversity Based on Local Ecological Knowledge

One of the expected effects of global change is increased variability in the abundance and distribution of living organisms, but information at the appropriate temporal and geographical scales is often lacking to observe these patterns. Here we use local knowledge as an alternative information source to study some emerging changes in Mediterranean fish diversity. A pilot study of thirty-two fishermen was conducted in 2009 from four Mediterranean locations along a south-north gradient. Semi-quantitative survey information on changes in species abundance was recorded by year and suggests that 59 fish species belonging to 35 families have experienced changes in their abundance. We distinguished species that increased from species that decreased or fluctuated. Multivariate analysis revealed significant differences between these three groups of species, as well as significant variation between the study locations. A trend for thermophilic taxa to increase was recorded at all the study locations. The Carangidae and the Sphyraenidae families typically were found to increase over time, while Scombridae and Clupeidae were generally identified as decreasing and Fistularidae and Scaridae appeared to fluctuate in abundance. Our initial findings strongly suggest the northward expansion of termophilic species whose occurrence in the northern Mediterranean has only been noted previously by occasional records in the scientific literature

First records of Sphyraena chrysotaenia (Klunzinger, 1884) and Diadema setosum (Leske, 1778) in the Marine Protected Area of Zakynthos Island (Ionian Sea, Greece)

In 2021, three specimens of the Lessepsian yellowstripe barracuda Sphyraena chrysotaenia and eight specimens of the Indo-Pacific needle-spined sea urchin Diadema setosum were recorded along the coasts of Zakynthos Island, some within the Marine Protected Area

Management priorities for marine invasive species

Managing invasive alien species is particularly challenging in the ocean mainly because marine ecosystems are highly connected across broad spatial scales. Eradication of marine invasive species has only been achieved when species were detected early, and management responded rapidly. Generalized approaches, transferable across marine regions, for prioritizing actions to control invasive populations are currently lacking. Here, expert knowledge was elicited to prioritize 11 management actions for controlling 12 model species, distinguished by differences in dispersion capacity, distribution in the area to be managed, and taxonomic identity. Each action was assessed using five criteria (effectiveness, feasibility, acceptability, impacts on native communities, and cost), which were combined in an ‘applicability’ metric. Raising public awareness and encouraging the commercial use of invasive species were highly prioritized, whereas biological control actions were considered the least applicable. Our findings can guide rapid decision-making on prioritizing management options for the control of invasive species especially at early stages of invasion, when reducing managers' response time is critical

Coastal observatories for monitoring of fish behaviour and their responses to environmental changes

The inclusion of behavioral components in the analysis of a community can be of paramount importance in marine ecology. Diel (i.e., 24-h based), seasonal activity rhythms, or longer durational in behavioral responses can result in shifts in populations, and therefore on measurable abundances. Here, we review the value of developing cabled video observatory technology for the remote, long-term, and high-frequency monitoring of fish and their environments in coastal temperate areas. We provide details on the methodological requirements and constraints for the appropriate measurement of fish behavior over various seasonal scales (24 h, seasonal, annual) with camera systems mounted at fixed observatory locations. We highlight the importance of using marine sensors to simultaneously collect relevant environmental data in parallel to image data acquisition. Here we present multiparametric video, oceanographic, and meteorological data collected from the Mediterranean observatory platform, OBSEA (www.​obsea.​es; 20 m water depth). These data are reviewed in relation to ongoing and future developments of cabled observatory science. Two key approaches for the future improvement of cabled observatory technology are: (1) the application of Artificial Intelligence to aid in the analysis of increasingly large, complex, and highly interrelated biological and environmental data sets, and (2) the development of geographical observational networks to enable the reliable spatial analysis of observed populations over extended distances