The loggerhead turtle Caretta caretta population of the Eastern Mediterranean faces a host of climate change-induced challenges in the future. The sex of hatchlings is determined by incubation temperature during a genital differentiation phase, producing more females at higher temperatures (generalised here to >29 degrees C). Without behavioural change, either by nesting at a cooler time of year or altering microsite selection, there is a risk that climate change-induced female bias may place the population at risk. Through a combination of in situ dataloggers and biophysical modelling, we estimated offspring sex ratios across 8 Mediterranean countries, including established rookeries (>50 nests yr(-1), n = 17 in 4 countries) and smaller rookeries (n = 5) and beaches that do not currently host nesting (n = 9). Here, we provide for the first time a regional estimate of hatchling sex ratio: 74.5% female, which may rise to 91.2% by 2100 per IPCC SSP3-7.0. Of the well-established rookeries, Patara, T & uuml;rkiye, has the lowest female production (49%), while Alagadi, Northern Cyprus, produces the most females (96%). Several smaller beaches, particularly in North Africa, exhibit male-biased production, including Lake Bardawil, Egypt (19% female), and Kuriat Islands, Tunisia (23% female). Beaches without current nesting activity, such as Qerret, Albania, could provide significant male production (6% female). A phenological shift of 20 d could potentially decrease female hatchling proportion upwards of 60% in areas with rapid mid-summer warming. We present as part of this work an interactive tool to explore these warming and phenological shift scenarios, providing a novel framework to assess the impact of hypothetical phenological and abundance changes on resultant primary sex ratios.

Mediterranean monk seal (Monachus monachus) sightings along the Lebanese coast were recorded between 2020 and 2025. This study aims to provide insights into the consistency of monk seal presence, their habitat use, and their feeding behaviour in the studied area. The research relied on photographic and video materials gathered from social media reports, as well as contributions from local fishers and divers. A total of 43 sightings were recorded, with photo-identification possible for 34 of these. The study confirmed the presence of at least three distinct individuals, including one adult female frequently utilizing marine caves in Amchit and Rawsheh. Video recordings of feeding behaviour revealed prey species such as grey mullet and octopus, which are also targeted by local fisheries, suggesting potential conflicts between the seals and the fishing sector. This study emphasizes the need for a more systematic, long-term monitoring approach, including the use of infrared cameras, to identify suitable habitats and more accurately assess seal presence. The research further recommends a region-wide effort to understand monk seal movements within the Levantine Basin and to support broader conservation initiatives for the species.

The brown mussel Perna perna (Linnaeus, 1758) is a circumtropical species with a complex biogeographical history, recently expanding in the eastern Mediterranean. While the status of Perna perna in the Mediterranean Sea remains debated, specifically whether it should be classified as native, cryptogenic, or an introduced species, it has been recorded in several southern Levantine countries, likely facilitated by rising sea surface temperatures. Perna perna is known to thrive in warm-temperate to subtropical waters, typically tolerating temperatures between 12 and 32 degrees C, with optimal performance above 20 degrees C. These thermal preferences overlap with the increasingly warm conditions of the Levantine Basin, which has been identified as one of the fastest-warming marine regions in the Mediterranean. This study reports the first confirmed record of P. perna in Lebanese waters, based on live specimens collected from mediolittoral rocks in Saida on September 7, 2024. Given the region's proximity to the Suez Canal, a principal route for Lessepsian introductions, and its documented susceptibility to non-indigenous species invasions and climate-induced ecosystem shifts, the establishment of P. perna raises concerns about potential impacts on local biodiversity and native assemblages. Furthermore, P. perna has been reported to form dense populations in other parts of its introduced range, where it has displaced native mussels and altered community structures, underscoring its relevance as a species of biosecurity concern. This finding highlights the need for continued monitoring, regional collaboration, and adaptive management strategies to mitigate the potential ecological consequences of its spread in the Levantine Basin.

The analysis of the genetic structure of populations of the Mediterranean green sea turtle (Chelonia mydas, C. mydas) is essential for the development of sustainable management strategies and in ensuring the effective conservation of the species. In order to obtain more comprehensive data on the genetic connectivity and migratory behaviour of sea turtles, genetic diversity should be evaluated in detail using advanced molecular markers. Maternal genetic diversity based on mitochondrial short tandem repeats (mtSTRs) in the D-loop region of 327 samples was assessed to elucidate the genetic connectivity and population structure of C. mydas in the Mediterranean. Among the 42 haplotypes identified, nine novel haplotypes were found in stranded individuals from T & uuml;rkiye, four from Cyprus and one from Tunisia. The origins of the stranded individuals were also investigated through mixed stock analysis. The results show that the genetic structure of C. mydas populations in the Mediterranean is more complex than previously thought. In particular, the Turkish coasts stand out as an important migration and feeding area where different genetic groups come together. The findings suggest that protecting nesting and feeding areas, expanding genetic monitoring and enhancing international conservation cooperation are essential for the species' sustainability. In summary, this study enhances our understanding of the genetic structure of Mediterranean C. mydas populations and provides essential insights to support evidence-based conservation strategies aimed at ensuring the long-term viability of regional management units (RMUs) within the Mediterranean.

Ostreopsis spp. blooms have been occurring in the last two decades in the Mediterranean Sea in association with a variety of biotic and abiotic substrata (macroalgae, seagrasses, benthic invertebrates, sand, pebbles and rocks). Cells proliferate attached to the surfaces through mucilaginous trichocysts, which lump together microalgal cells, and can also be found in the plankton and on floating aggregates: such tychoplanktonic behavior makes the quantitative assessment of blooms more difficult than planktonic or benthic ones. Different techniques have been so far applied for quantifying cell abundances of benthic microalgae for research, monitoring and risk assessment purposes. In this context, the Benthic Dinoflagellates Integrator (BEDI), a non-destructive quantification method for benthic dinoflagellate abundances, was developed and tested within the EU ENPI-CBCMED project M3-HABs. This device allows mechanical detachment of cells without collecting the benthic substrate, providing an integrated assessment of both epiphytic and planktonic cells, i.e. of the number of cells potentially made available in the water volume from “resuspension” which could have harmful effects on other organisms (including humans).The present study confirms the effectiveness of the BEDI sampling device across different environments across the Mediterranean Sea and constitutes the first large-scale study of Ostreopsis spp. blooms magnitude in function of different macro- and meso-habitat features across the basin.

The loggerhead sea turtle ( Caretta caretta ), has the widest distribution among sea turtle species in the Mediterranean, requiring regional and international collaborations in addition to local efforts to better inform conservation actions. Molecular techniques are powerful tools for the assessment of population dynamics at large scales, especially in determining the connectivity among different nesting and foraging sites, and genetic diversity. In this study, a large sample was collected synchronously in the nesting areas located in the north, south and eastern Mediterranean. Recently confirmed nesting sites from Albania and other nesting sites represented by lower sample sizes were also included in order to better assess the genetic composition of the region’s rookeries. Samples from 698 individuals were collected and the longer (815 bp) mtDNA D-loop fragment of these samples was sequenced. We recorded 15 haplotypes, three of which were novel. In addition, our results show that some haplotypes considered of Atlantic origin, have a wider dispersal in the Mediterranean than previously thought, albeit with low levels of representation. Our results contribute to determining the likely origin of haplotypes that were previously only recorded from foraging sites. They highlight the utility of broad-scale sampling, with increased sample sizes and the longer mtDNA sequence to determine genetic diversity and connectivity. This study also demonstrates the importance of continued monitoring for the contribution of Atlantic-origin haplotypes to the Mediterranean population and the effects of climate change on the resident Mediterranean population, which is expected to expand its geographical range for reproduction. This work is important for, mixed stock analyses (MSA) that seek to determine the natal regions of stranded or accidentally caught sea turtles and those purposefully obtained from foraging sites. In doing so biogeographic linkages between areas of the Mediterranean can be elucidated for conservation purposes.

The basket star Astrospartus mediterraneus (Risso, 1826) is reported for the first time in the Libyan waters. The species was collected by trawling at 73 m of depth in Tripoli waters. This note gives details about this observation.

The recent paper by Bariche Fricke (2020) presents an updated checklist of the marine fish species in Lebanon including 367 fish species, 70 non-indigenous and 28 new records. According to Bariche Fricke (2020), the inventory is based on the published scientific papers related to the marine fishes in Lebanon, since Gruvel (1928, 1931), as well as grey literature, images published in newspapers or on local websites and social media. However, important scientific papers and published reports, providing important data on marine fishes in Lebanon, were missed. Hereby we cite twelve scientific papers: [Nafpaktitis (1963), Bath (1977), Shiber (1981), Moosleitner (1988), Lakkis et al. (1996), Bariche (2006), Bariche et al. (2006); Bitar et al. (2007), Bariche Trilles (2008), Bitar (2010), Khalaf et al. (2014), and Bitar (2015) in Zenetos et al. (2015)], twelve national reports [the national report of Abboud Abi Saab et al. (2003) under the framework of a Libano-Franco cooperation, the national report of Majdalani (2005) under the framework of the Ministry of Agricultue (MoA), the two reports in cooperation between the Food Agriculture Organisation (FAO) and the National Council for Scientific Research (CNRS) Lelli et al. (2006), and Sacchi Dimech (2011), and the eight national reports in collaboration with the Ministry of Environment (MoE) and the organizations of: (i) aecid/Tragsa as MoE/aecid/Tragsa (2009), (ii) International Union for Conservaion Nature (IUCN)- Specially Protected Areas Regional Activity Centre (SPA/RAC) as IUCN-SPA/RAC (2017), (iii) the SPA/RAC as Bitar (2008), RAC/SPA-UNEP/MAP (2014), IUCN-SPA/RAC (2017), and SPA/RAC-UN Environment/MAP (2017, 2018a, 2018b), and finally, the book of Lakkis (2013)]. Concerning the publication of Lakkis et al. (1996), and the book of Lakkis (2013), only the valid and confirmed/ or proofed marine fish species were listed in Table 1. While, the questionable/ doubtful marine fish records from those two references were listed in Table 2 and Table 3 (see suppl.file 2, and 3). In this context and based on the Lebanese literature, Bariche Fricke (2020) missed the reports of 9 species (Table 1). Therefore, the list of marine fish of Lebanon (Bariche Fricke, 2020) is enriched reaching 376 species, 71 of which are non-indigenous species (See suppl.file 1). In agreement with Zenetos Galanidi (2020) we state that even the current update may contain errors, as species invasions are dynamic phenomena, where new information continually comes to light, whether from new observations or from re-examination of older material, changes in nomenclature and phylogenetic studies.

This article includes twenty (20) new records of alien and cryptogenic species in the Mediterranean Sea, belonging to six (6) Phyla (Rhodophyta, Tracheophyta, Mollusca, Arthropoda, Bryozoa, and Chordata) distributed from the Eastern Mediterranean to the Sea of Alboran. The records are reported from nine (9) countries and can be classified into two categories: new records for the Mediterranean Sea and new records of non-indigenous species expanding within the Mediterranean Sea. The first category includes the gastropod Turbo radiatus from Lebanon coasts, the portunid crab Charybdis (Charybdis) natator from Tunis southern lagoon, the mollusc Thuridilla mazda from South Spain, and the nudibranch Okenia picoensis from the Alboran coasts of Spain and from Malta. The second category includes the bivalve Nudiscintilla cf. glabra from the Aegean coast of Turkey, the rhodophyte Colaconema codicola from the North Aegean coasts of Greece, the naked band gaper Champsodon nudivittis from the Sea of Marmara, Turkey. Also, the brachyuran Gonioinfradens giardi from the Greek Ionian waters, the codlet Bregmaceros nectabanus from the Croatian coasts of the Adriatic Sea, and the bryozoan Arbopercula tenella and copepod Parvocalanus crassirostris both from the Gulf of Trieste, Slovenian and Italian coasts, respectively. New records were also reported for the ascidian Distaplia bermudensis from brackish the Gulf of Naples, Italy, the damselfish Abudefduf cf. saxatilis and the seagrass Halophila stipulacea from Sardinia, Tyrrhenian Sea, and for the fish Paranthias furcifer from the harbour of Almeria, Alboran Sea, Spain. Through these records, an understanding of the expanding mechanisms and processes and, if possible, the development of mitigation measures within the region will be further facilitated.

The presence of the black wing flyingfish Hirundichthys rondeletii (Valenciennes, 1846) was reported for the first time from the Lebanese waters. It was caught by a professional fisherman in Beirut on 27 December 2009. The present note reports details about this record.

The Indo-Pacific jellyfish Cotylorhiza erythraea Stiasny, 1920 is reported for the first time from the Lebanese waters. The species was observed and photographed by a professional diver on 28 July 2020 at a depth of 5 m in Tyre, south of Lebanon. The present note presents details about this observation.

A young specimen of the blackfish, Centrolophus niger (Gmelin, 1789) was reported for the first time from the Lebanese waters. It was caught and photographed by a professional fisherman in Beirut, on 15th November 2014. The present note reports details about this first record.

The two non-native ctenophores Beroe ovata Bruguiere, 1789 and Mnemiopsis leidyi A.Agassiz, 1865, were reported off the Lebanese waters. Beroe ovata Bruguiere, 1789, a specializedpredator on Mnemiopsis leidyi, was collected and photographed, on May 2th 2019 duringfieldwork in Beirut waters. While, Mnemiopsis leidyi was reported for the first time on April 27th2009, to date, it is widely distributed from the south to the north of the Lebanese waters. The mostpossible pathway of the introduction of those species is a spreading, or bringing with ballastwaters from the Black Sea.

This article includes 23 new records of alien and cryptogenic species in the Mediterranean Sea, belonging to 4 Phyla (Chordata, Echinodermata, Arthropoda and Mollusca), distributed from the Alboran to the Levantine Sea. Records are reported from eight countries listed from West to East as follows: Algeria: new records of the Atlantic blue crab Callinectes sapidus; Spain: further spread and establishment of the sea slug Lamprohaminoea ovalis in continental shores; Tunisia: first record of the Atlantic Blue Crab Callinectes sapidus in the Gulf of Gabes; Italy: a new occurrence of the pufferfish Lagocephalus sceleratus in Northern Ionian waters; first record of Cephalopholis taeniops in the Ionian Sea; first record of the redlip blenny, Ophioblennius atlanticus in the Ionian Sea; Slovenia: first record of the isopod Paranthura japonica in Slovenia; Greece: first record of the molluscs Eunaticina papilla, Plocamopherus ocellatus and the fish Cheilodipterus novemstriatus; first record of the ascidian Ecteinascidia turbinata in Kriti; the long-spined sea urchin Diadema setosum in the Ionian Sea; Turkey: first record of the sea spider Ammothea hilgendorfi; the stomatopod Cloridina cf. ichneumon; the fishes Pempheris rhomboidea from the Sea of Marmara and Paranthias furcifer from the Aegean Sea; Lebanon: new records of the fishes Arothron hispidus, Rachycentron canadum, Heniochus intermedius and Acanthurus monroviae; first record of Acanthostracion polygonius. The records of Cloridina cf. ichneumon from southern Turkey and the fish Acanthostracion polygonius from Lebanon, both being the first Mediterranean records, are noteworthy.

Heteropriacanthus cruentatus (Lacepède, 1801) was reported for the first time in the Mediterranean Sea from the Lebanese deep sea. A photograph of the glasseye fish was posted on the social media network Facebook. The specimen was caught from the deep sea of Lebanon on 29 April 2019 by a recreational longline fishermen.

Macroalgae is one of the Biological Quality Elements (BQE) used by several indexes conceived in the European Water Framework Directive (WFD) for the assessment of the Ecological status of coastal water bodies. Among them, CARLIT index, based on the cartography of rocky-shore littoral communities, has been extensively and successfully applied in the Western Mediterranean Sea. In this study CARLIT was applied for the first time in the Levantine Sea, along the Lebanese shoreline in order to test the suitability of this method in the peculiar ecological conditions of the Levantine Sea and have a first assessment of its ecological status. The choice of proper reference sites is a focal point in the fulfillment of the WFD. In order to ensure accurate calculation of the ecological status of the Lebanese coast, the calculations of the reference conditions (RC) were performed using the values calculated in the Lebanese reference area, the Northwestern (NW) Mediterranean RC proposed in the first application of the CARLIT method and the Adriatic Sea RC. The results showed that the calculated ecological quality ratio values (EQR) based on Lebanese RC is particularly important when considering the principle of the WFD to reach and maintain a good Ecological Status. Overall, the EQR values were well correlated with anthropogenic pressures, as assessed by the LUSI and MA-LUSI indexes. In addition, this method allowed the collection of accurate information on the distribution and abundance of shallow-water communities, especially of those deserving protection (e.g. Cystoseira forests). Thus, the present paper represents a baseline for future studies and gives useful tools for the management of human impacts on the Lebanese coast.

Le but de cette these est de mieux connaitre les effets des activites anthropiques sur l'etat de conservation des habitats cotiers importants (forets de Cystoseira et trottoirs a Vermets) dans une region peu connue de la Mediterranee : la cote Libanaise. Plusieurs approches sont appliquees pour la premiere fois le long de la cote Levantine, tel que l'indice CARLIT (cartographie des communautes benthiques du littoral rocheux), un outil concu pour evaluer l’Etat Ecologique (EE) dans le cadre de la Directive des Eaux (DCE 2000/60/UE). La description generale du littoral Libanais, resumant les principales caracteristiques environnementales et les activites anthropiques influencant les communautes benthiques, a souligne que la cote Libanaise a ete (et est actuellement) soumis a plusieurs pressions de plusieurs origines. L'application du CARLIT, base sur les communautes de macroalgues a fourni des idees importantes sur l’EE actuel de la cote rocheuse Libanaise en relation avec les impacts humains et a permis d’etablir une cartographie detaillee de la repartition et de l'abondance des communautes cotiers, en particulier des forets de Cystoseira et de Sargassum). L'etude de certains trottoirs a Vermets Libanais a permis d’evaluer leur etat actuel en fonction des differentes pressions humaines et confirmer qu’ils sont tres affectes et que peu sont encore vivants. Dans une perspective future et avec la decouverte de petrole et du gaz dans les eaux Libanaises, les ecosystemes marins Libanais seront soumis a plusieurs nouveaux menaces ; les recherches de cette these presentent une base de reference de l’EE de ces ecosystemes, permettant de les conserver et suivre leur evolution.

Vermetid reefs are a key intertidal habitat in the warm-temperate part of the Mediterranean Sea and in some subtropical and tropical regions in the Atlantic and Pacific oceans. This unique and highly diverse ecosystems is under siege due to both the high anthropogenic pressure and the global climate change, with documented local population declines in the Eastern Mediterranean. This study aims at evaluating the conservation state of vermetid reefs along the Lebanese coast (Eastern Mediterranean), where seawater warming, habitat degradation and coastal urbanization likely threaten their presence. In order to assess the conservation status of vermetid reefs in Lebanon, five sites were randomly selected among those belonging to three impact classes: i) not impacted (i.e. protected), ii) moderately impacted, and iii) impacted. Two different non-destructive methods were applied to assess the presence of living vermetids Dendropoma anguliferum (Monterosato, 1878) and Vermetus triquetrus (Bivona-Bernardi, 1832) which shape the reef, and the associated communities. Our results highlight that no living vermetid reefs were recorded in the impacted sites where evident signs of bio-physical erosion of the reef are already underway. Living individuals of Vermetus triquetrus were found in some not impacted and moderately impacted sites, while living individuals of the endemic reef-builder Dendropoma anguliferum were found only at very low densities at the not impacted (protected) site. Such findings corroborate preliminary observations of population decline in the Eastern Mediterranean, and of vermetid reefs vulnerability to human disturbances. This raises concerns about the near future persistence of vermetid reefs in the region, and represents a call for management and conservation actions to preserve this reef-building species in the Mediterranean Sea.

Écosystèmes côtiers du littoral libanais : état écologique, conservation, évolution Le but de cette thèse est de mieux connaître les effets des activités anthropiques sur l'état de conservation des habitats côtiers importants (forêts de Cystoseira et trottoirs à Vermets) dans une région peu connue de la Méditerranée : la côte Libanaise. Plusieurs approches sont appliquées pour la première fois le long de la côte Levantine, tel que l'indice CARLIT (cartographie des communautés benthiques du littoral rocheux), un outil conçu pour évaluer l’Etat Ecologique (EE) dans le cadre de la Directive des Eaux (DCE 2000/60/UE). La description générale du littoral Libanais, résumant les principales caractéristiques environnementales et les activités anthropiques influençant les communautés benthiques, a souligné que la côte Libanaise a été (et est actuellement) soumis à plusieurs pressions de plusieurs origines. L'application du CARLIT, basé sur les communautés de macroalgues a fourni des idées importantes sur l’EE actuel de la côte rocheuse Libanaise en relation avec les impacts humains et a permis d’établir une cartographie détaillée de la répartition et de l'abondance des communautés côtiers, en particulier des forêts de Cystoseira et de Sargassum). L'étude de certains trottoirs à Vermets Libanais a permis d’évaluer leur état actuel en fonction des différentes pressions humaines et confirmer qu’ils sont très affectés et que peu sont encore vivants. Dans une perspective future et avec la découverte de pétrole et du gaz dans les eaux Libanaises, les écosystèmes marins Libanais seront soumis à plusieurs nouveaux menaces ; les recherches de cette thèse présentent une base de référence de l’EE de ces écosystèmes, permettant de les conserver et suivre leur évolution.