Assessment of Human Health Impacts from Invasive Pufferfish (Attacks, Poisonings and Fatalities) across the Eastern Mediterranean.

The silver-cheeked toadfish Lagocephalus sceleratus (Gmelin 1789), and to a lesser degree the orange spotted toadfish Torquigener hypselogeneion (Bleeker, 1852), pose threats to human health from physical attacks and poisonings in the Eastern Mediterranean Sea. This study reviewed human health-related impacts resulting from these pufferfish, compiling and assessing records from online sources, the peer-reviewed literature, medical records, personal interviews, and observations across the Eastern Mediterranean in the years 2004 to 2023. A total of 198 events impacting human health were documented: 28 records of physical attacks, at least 144 non-lethal poisoning episodes, and 27 human fatalities resulting from consumption. The majority of the reported incidences occurred in Syria, Türkiye, and Lebanon. Most physical attacks occurred in summer, while most poisoning events occurred during winter. The number of recorded incidents greatly increased after 2019, especially with regard to poisonings, yet whether this is related to greater media attention, or to increased fish abundance is unclear. This is the first comprehensive study to collate findings on attacks, poisonings and fatalities caused by these pufferfish in the Mediterranean Sea, and may help in improving national health policies. We urge the continuation of national campaigns to caution residents and tourists of these species' high toxicities and potential aggressiveness.

Invasion genomics of lionfish in the Mediterranean Sea.

The rate of biological invasions is steadily increasing, with major ecological and economic impacts accounting for billions of dollars in damage as a result. One spectacular example is the western Atlantic invasion by lionfishes. In the Mediterranean Sea, invasions from the Red Sea via the Suez Canal (termed Lessepsian invasions) comprise more than 100 fish species, including a recent invasion by lionfish. In light of the devastating effects of lionfish in the Caribbean Sea, understanding the dynamics of Mediterranean lionfish invasion is crucial. The Lessepsian lionfish invasion started in 2012, and rapidly spread to the central Mediterranean. Here, we used thousands of RAD seq genomic markers to study the population dynamics of this invasion. While we did not find a reduction in genetic diversity between source (Red Sea) and invasive (Mediterranean) populations (i.e., bottleneck effects), we found evidence of population structure within the invasive range in the Mediterranean Sea. We found that loci that are potentially under selection may play an important role in invasion success (in particular, genes involved in osmoregulation and fin spine sizes). Genomic approaches proved powerful in examining the ecological and evolutionary patterns of successful invaders and may be used as tools to understand and potentially mitigate future invasions.

Genetic diversity and phylogenetic relationships of threadfin breams (Nemipterus spp.) from the Red Sea and eastern Mediterranean Sea.

The present work utilized partial sequences of cytochrome c oxidase subunit I (COI) to study Red Sea populations of threadfin breams (Nemipteridae), and compare their genetic diversity to that of Mediterranean Sea (Nemipterus randalli only) and Indo-Pacific populations. A Maximum Likelihood tree separated four fish species - N. randalli, N. japonicus, N. bipunctatus, and N. zysron - into four clades. Haplotype analyses revealed a strong case of the founder effect for the Lessepsian migrant N. randalli: Three haplotypes represented all sampled geographical ranges in the Mediterranean Sea and only one haplotype was shared with a Red Sea individual, presenting evidence that the colonizing population was founded by a small number of migrants. The Red Sea population of N. japonicus shared haplotypes with Persian Gulf and Indian Ocean populations, but South China Sea populations remained fully isolated. The haplotype networks of N. randalli and N. bipunctatus also revealed haplotype sharing between Red Sea and Indian Ocean populations. For N. zysron, one haplotype was shared between Indonesia and the Persian Gulf. We discuss the impact of continued usage of public database sequences of initially misidentified organisms and provide recommendations for avoiding distribution of sequences with incorrect scientific names.

The marine ichthyofauna of Lebanon: an annotated checklist, history, biogeography, and conservation status.

This is an annotated checklist of the marine fish species of Lebanon (Levant coast, eastern Mediterranean). It comprises a total of 367 fish species distributed in 159 families and 27 orders, out of which 70 species are non-indigenous and 28 are recorded for the first time from Lebanon. The checklist includes all names and citations of species found in the literature, as well as references to specimens available in museum collections. It also includes an updated zoogeographic distribution and conservation status for each species. Threats were estimated based on surveys and observations made over the last two decades; broadly categorized conservation actions were also suggested.

Habitat suitability, niche unfilling and the potential spread of Pterois miles in the Mediterranean Sea.

The common lionfish Pterois miles has rapidly spread across the eastern Mediterranean Sea. We compiled occurrence data from both native and invaded range under the framework of Species Distribution Modelling (SDM). Through a construction of an environmental suitability model and estimation of spread rates we investigated the lionfish climate niche in both its native and invaded domains, this latter represented by the Mediterranean region. Model projections allowed to identify suitable areas for lionfish establishment in the Mediterranean. Spread analysis suggested that a further geographical expansion in this basin could be completed within the next years. Our results did not provide evidence for niche expansion but highlighted a high degree of niche unfilling thus prospecting a likely spread of Mediterranean lionfish invasion beyond the predictions of current SDMs. These findings provide novel inputs to forecast the future geographical evolution of the lionfish in the Mediterranean Sea and asses the related risk of invasion.

Climate change, biological invasions, and the shifting distribution of Mediterranean fishes: A large-scale survey based on local ecological knowledge.

Climate change and biological invasions are rapidly reshuffling species distribution, restructuring the biological communities of many ecosystems worldwide. Tracking these transformations in the marine environment is crucial, but our understanding of climate change effects and invasive species dynamics is often hampered by the practical challenge of surveying large geographical areas. Here, we focus on the Mediterranean Sea, a hot spot for climate change and biological invasions to investigate recent spatiotemporal changes in fish abundances and distribution. To this end, we accessed the local ecological knowledge (LEK) of small-scale and recreational fishers, reconstructing the dynamics of fish perceived as "new" or increasing in different fishing areas. Over 500 fishers across 95 locations and nine different countries were interviewed, and semiquantitative information on yearly changes in species abundance was collected. Overall, 75 species were mentioned by the respondents, mostly warm-adapted species of both native and exotic origin. Respondents belonging to the same biogeographic sectors described coherent spatial and temporal patterns, and gradients along latitudinal and longitudinal axes were revealed. This information provides a more complete understanding of the shifting distribution of Mediterranean fishes and it also demonstrates that adequately structured LEK methodology might be applied successfully beyond the local scale, across national borders and jurisdictions. Acknowledging this potential through macroregional coordination could pave the way for future large-scale aggregations of individual observations, increasing our potential for integrated monitoring and conservation planning at the regional or even global level. This might help local communities to better understand, manage, and adapt to the ongoing biotic transformations driven by climate change and biological invaders.

DNA Taxonomy Confirms the Identity of the Widely-Disjunct Mediterranean and Atlantic Populations of the Tufted Ghost Crab Ocypode cursor (Crustacea: Decapoda: Ocypodidae).

The distribution area of the tufted ghost crab Ocypode cursor includes two widely separate sub-areas, i.e. the tropical and subtropical Atlantic coasts of Africa and Macaronesia, and the central-eastern Mediterranean basin. The current disjunct distribution of the species is possibly the remnant of a previous wider and continuous distribution area that was fragmented during the Pleistocene, with the disappearance of the species from the temperate Atlantic Ocean and the western Mediterranean basin, and its survival in the warmer areas of the eastern Atlantic and the Mediterranean Sea. Such disjunction is thus compatible with an ancient isolation between the Mediterranean and Atlantic populations of the species, which could in fact constitute two well-characterized independent evolutionary lineages, or even two cryptic species. Unexpectedly, the sequencing of a fragment of the mtDNA COI gene from Mediterranean and Atlantic Ocypode cursor allopatric populations showed the cohesion of the species throughout its distribution range, and the nesting of Mediterranean populations within the single Atlantic population studied. This pattern is hereby tentatively ascribed to an incomplete lineage sorting due to the large population sizes of both the Atlantic and Mediterranean subpopulations of the species. The current westward expansion of the species in the Mediterranean Sea originating from the Levantine basin, due to ongoing regional sea warming, follows a typical phalanx dispersal mode.

Genetics reveal the identity and origin of the lionfish invasion in the Mediterranean Sea.

Following aquarium releases, invasive lionfishes have colonized large areas of the Caribbean and western Atlantic, resulting in an immense ecological damage. The early stages of that invasion are poorly known. Indeed, a lag of time between the introduction and detection often preclude genetic characterization of that crucial phase. With elevated awareness, the recent invasion of Pterois miles was quickly detected in the Mediterranean Sea. We hereby show that the very first individuals establishing populations in the Mediterranean Sea display haplotypes that nest within the large genetic diversity of Red Sea individuals, thus indicating an invasion via the Suez Canal. We also show that only two haplotypes are detected in the Mediterranean Sea, suggesting that few individuals may have been involved in the invasion. Thus, we conclude that the Mediterranean invasion is the result of a movement of individuals from the Red Sea, rather than from other means, and that low genetic diversity does not seem to have a negative effect on the success and spread of lionfish into the Mediterranean Sea.

Characterization of the Cultivable Gut Microflora in Wild-Caught Mediterranean Fish Species.

BACKGROUND: Microflora of the gastrointestinal tract plays important roles in food digestion, nutrient absorption and in host defense against ingested pathogens. Several studies have focused on the microflora of farmed fishes, but the gut flora of wild fishes remains poorly characterized. The aim of this work was to provide an overview of the bacteria colonizing the gut of wild-caught fishes and to determine whether some bacterial species can be pathogenic. RESULTS: We isolated cultivable bacteria from fifteen wild-caught Mediterranean fish species corresponding to different habitat, diet and origin. Bacterial species identity was determined by 16s rRNA gene sequencing for the 61 isolates. The potential pathogenicity of isolated bacteria was investigated using fruit fly (Drosophila melanogaster) and zebrafish (Danio rerio) as model organisms. Two bacterial strains (Serratia sp. and Aeromonas salmonicida) were lethal when microinjected to Drosophila, while zebrafish did not develop any disease when exposed to any of 34 isolated bacterial strains. However, it was interesting to note that two bacterial strains (Shewanella and Arthrobacter) isolated from marine fishes were able to colonize the guts of freshwater zebrafish. CONCLUSION: The results of this study give an overview of the bacterial species found in the guts of wild fishes living off Beirut seashore. It shows that some parameters believed to be limiting factors to host-gut colonization by bacteria can be overcome by some species. This pilot study could be extended by sampling a larger number of fish species with several specimens per fish species, and by identifying uncultivable bacteria that reside in the fish guts. Our results may have implications for the utilization of certain bacterial species in fish farming or their use as bio-indicators for water and/or food quality.

Predicting future thermal habitat suitability of competing native and invasive fish species: from metabolic scope to oceanographic modelling.

Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. The increasing success of these species may be related to their higher physiological performance compared with indigenous ones. Here, we determined the effect of temperature on the aerobic metabolic scope (MS) of two herbivorous fish species that occupy a similar ecological niche in the Mediterranean Sea: the native salema (Sarpa salpa) and the invasive marbled spinefoot (Siganus rivulatus). Our results demonstrate a large difference in the optimal temperature for aerobic scope between the salema (21.8°C) and the marbled spinefoot (29.1°C), highlighting the importance of temperature in determining the energy availability and, potentially, the distribution patterns of the two species. A modelling approach based on a present-day projection and a future scenario for oceanographic conditions was used to make predictions about the thermal habitat suitability (THS, an index based on the relationship between MS and temperature) of the two species, both at the basin level (the whole Mediterranean Sea) and at the regional level (the Sicilian Channel, a key area for the inflow of invasive species from the Eastern to the Western Mediterranean Sea). For the present-day projection, our basin-scale model shows higher THS of the marbled spinefoot than the salema in the Eastern compared with the Western Mediterranean Sea. However, by 2050, the THS of the marbled spinefoot is predicted to increase throughout the whole Mediterranean Sea, causing its westward expansion. Nevertheless, the regional-scale model suggests that the future thermal conditions of Western Sicily will remain relatively unsuitable for the invasive species and could act as a barrier for its spread westward. We suggest that metabolic scope can be used as a tool to evaluate the potential invasiveness of alien species and the resilience to global warming of native species.

On the Monacha species of Lebanon (Gastropoda, Hygromiidae).

In this paper, all seven hitherto known species of the hygromiid genus Monacha from Lebanon are briefly characterised and illustrated, and distribution maps are supplied (Monacha (Monacha) syriaca (Ehrenberg, 1831), Monacha (Monacha) nummus (Ehrenberg, 1831), Monacha (Monacha) obstructa (L. Pfeiffer, 1842), Monacha (Monacha) crispulata (Mousson, 1861), Monacha (Monacha) solitudinis (Bourguignat, 1852), Monacha (Monacha) bari Forcart 1981, and Monacha (Monacha) cf. compingtae (Pallary, 1929)). One species, Monacha (Monacha) bari Forcart, 1981, is recorded for the country for the first time, and its relationship to Monacha (Monacha) compingtae (Pallary, 1929) is discussed. Based on recently collected specimens, the genital organs of a long time ignored species, Helix solitudinis Bourguignat, 1852 could be investigated. It is here re-described as a Monacha species endemic for Lebanon.

Lack of a genetic bottleneck in a recent Lessepsian bioinvader, the blue-barred parrotfish, Scarus ghobban.

The present study investigates the genetic diversity of Scarus ghobban, a recently introduced parrotfish in the Mediterranean Sea via the Suez Canal. Two mitochondrial and one nuclear DNA regions were sequenced and phylogenetic relationships investigated, from samples collected from Lebanon and across its natural range. Scarus ghobban clustered in two major clades, Pacific Ocean and Indian Ocean, indicating strong population structure, or cryptic speciation. Expectedly, Mediterranean samples clustered with Indian Ocean-Red Sea individuals. However, unlike other recent Lessepsian invaders, S. ghobban displayed high genetic diversity. These results underscore that genetic diversity is a poor predictor of success of an invasive species.

Anilocra pilchardi n. sp., a new parasitic cymothoid isopod from off Lebanon (Eastern Mediterranean).

Anilocra pilchardi n. sp. is described from several specimens collected mainly from clupeiform fishes from off Lebanon. Various stages of the parasite are considered: ovigerous and non-ovigerous females, male and intramarsupial larvae. Taxonomic comments on the relationship of A. pilchardi to other congeneric species are given. A. pilchardi belongs to a particular group of Anilocra species previously known only from the Indo-Pacific Region.