The last stage in the life history of the European conger eel Conger conger: a transformation before death.

The taxonomic, morphological and meristic features of a dark eel caught by commercial trawling off the Gulf of Patti, southern Tyrrhenian Sea, Mediterranean Sea, February 17, 2017, showed it to be a female Conger conger. Histological analysis of gonads demonstrated that the individual was in a post-spawning phase. X-ray radiographs showed widespread decalcification of skeleton and teeth loss, confirming a strong mobilisation of somatic energy reserves needed for reproductive development.

Turnovers of Sex-Determining Mutation in the Golden Pompano and Related Species Provide Insights into Microevolution of Undifferentiated Sex Chromosome.

The suppression of recombination is considered a hallmark of sex chromosome evolution. However, previous research has identified undifferentiated sex chromosomes and sex determination by single SNP in the greater amberjack (Seriola dumerili). We observed the same phenomena in the golden pompano (Trachinotus ovatus) of the same family Carangidae and discovered a different sex-determining SNP within the same gene Hsd17b1. We propose an evolutionary model elucidating the turnover of sex-determining mutations by highlighting the contrasting dynamics between purifying selection, responsible for maintaining W-linked Hsd17b1, and neutral evolution, which drives Z-linked Hsd17b1. Additionally, sporadic loss-of-function mutations in W-linked Hsd17b1 contribute to the conversion of W chromosomes into Z chromosomes. This model was directly supported by simulations, closely related species, and indirectly by zebrafish mutants. These findings shed new light on the early stages of sex chromosome evolution.

Bridging the gap in fishing effort mapping: a spatially-explicit fisheries dataset for Campanian MPAs, Italy.

Recent technological advancements have facilitated the extensive collection of movement data from large-scale fishing vessels, yet a significant data gap remains for small-scale fisheries. This gap hinders the development of consistent exploitation patterns and meeting the information needs for marine spatial planning in fisheries management. This challenge is specifically addressed in the Campania region of Italy, where several Marine Protected Areas support biodiversity conservation and fisheries management. The authors have created a spatially-explicit dataset that encompasses both large-scale (vessels exceeding 12 meters in length) and small-scale (below 12 meters) fishing efforts. This dataset (available at https://doi.org/10.6084/m9.figshare.23592006 ) is derived from vessel tracking data and participatory mapping. It offers insights into potential conflicts between different fishing segments and their interactions with priority species and habitats. The data can assist researchers and coastal management stakeholders in formulating policies that reduce resource competition and promote ecosystem-based fisheries management. Furthermore, the provided mapping approach is adaptable for other regions and decision-making frameworks, as we are committed to sharing the tools and techniques we employed.

Integrated approach for marine litter pollution assessment in the southern Tyrrhenian Sea: Information from bottom-trawl fishing and plastic ingestion in deep-sea fish.

Marine litter pollution threatens marine ecosystems and biodiversity conservation, particularly on seafloors where all anthropogenic waste naturally sinks. In this study, we provide new information on the composition, density and origin of seafloor macrolitter as well as on plastic ingestion in deep-sea fish from bottom-trawling by-catch in the southern Tyrrhenian Sea. Plastic constituted the highest fraction of litter in terms of density (64 %) and weight (32 %) and was also retrieved in the gastrointestinal traits of Chlorophthalmus agassizi, Coelorhynchus coelorhynchus and Hoplosthethus mediterraneus. FT-IR spectroscopy analysis on the seafloor macrolitter and the ingested plastics revealed the presence of artificial polymers including PE, PET/polyester, PA widely used for food packaging, plastic bags and several common products, especially Single Use Plastic (SUP). These results underline how poor waste management schemes or their incorrect application strongly contribute to marine litter accumulation on seafloors and plastic ingestion in deep-sea fish.

How Rare Are Argonautoidea Octopuses in the Mediterranean? New Data from Stranding Events, Stomach Contents and Genetics.

The present paper represents the first all-encompassing study on all Mediterranean holopelagic octopods belonging to Argonautoidea (Argonauta argo, Ocythoe tuberculata, Tremoctopus gracilis, Tremoctopus violaceus). Argonautoidea octopuses were collected by different sampling methods in the Strait of Messina and southern Tyrrhenian Sea. The aim of this paper was to improve knowledge, using information from different data sources, such as the study of stranded individuals or accidental caught specimens, as well as the analysis of stomach content of large pelagic fishes. Moreover, we investigated their taxonomic profile through the amplification of the mitochondrial cytochrome c oxidase subunit I (COI). Overall, 47 fresh holopelagic octopods were collected, including valuable records of rare males. Moreover, 330 Argonautoidea octopuses were found in the stomachs of 800 predators. The results provided evidence that these cephalopods are more abundant than thought in the past. The molecular approach supported the ecological results with interesting insights. The similarity-based identifications and tree-based methods indicated that three females could be identified as Tremoctopus violaceus in agreement with their morphological classifications. The sequences obtained from the two T. gracilis individuals were clustered with the sequences of Tremoctopus violaceus from the Gulf of Mexico and were differentiated from the sequences attributed to T. gracilis and T. robsoni. The study represents a valuable contribution to the genetic characterization of Mediterranean individuals of the genera Tremoctopus, Argonauta and Ocythoe.

The waste collector: information from a pilot study on the interaction between the common octopus (Octopus vulgaris, Cuvier, 1797) and marine litter in bottom traps fishing and first evidence of plastic ingestion.

Few studies focused on behaviour adaptations of organisms to marine litter (ML) pollution in Mediterranean Sea. This research, investigates on some behavior traits of Octopus vulgaris, focusing on the interaction with ML during the artisanal fishing activities by the bottom traps in a small coastal area of the southern Tyrrhenian Sea. For the first time, this pilot study uses an integrated approach based on the Fishermen Ecological Knowledge as well as the analysis of ML found in the traps. First assessment of plastic ingestion in this species are also reported. Plastic and metal were the predominant ML categories observed into the bottom traps. A total of 62 plastics, mainly small microplastics and fibres shaped, were ingested. The ML finding in the bottom traps suggests an interesting behavior of the common octopus regarding its interaction with ML, in fact, it seems to bring ML inside its dens, as a collector.

Importance of the Lunar Cycle on Mesopelagic Foraging by Atlantic Bluefin Tuna in the Upwelling Area of the Strait of Messina (Central Mediterranean Sea).

The influence of the lunar cycle on bluefin tuna foraging in the upwelling area of the Strait of Messina was investigated by exploring trophic interaction with mesopelagic fish and cephalopod prey. To focus on how the lunar cycle could affect availability of mesopelagic prey for this predator, we tested potential differences in the diet related to each lunar phase. Moreover, we considered two potential impacts of the lunar cycle: the lunar irradiance and the strength of currents. Overall, 2672 prey items were mesopelagic fish and cephalopods, representing 60.7% of overall diet by number. The main mesopelagic fish prey items were lanternfishes and dragonfishes, while Onychoteuthis banksii was the most important cephalopod prey. In summary, the Strait of Messina has highly specific hydrodynamic and biological features which strongly depend on upwelling currents, which in turn are influenced by the lunar cycle (new and full moon with strong currents, quarters with fewer currents). Upwelling causes water mixing, bringing to the surface a large amount of mesopelagic fauna which become more readily available to tuna. Lunar irradiance contributes to the variation of prey composition, increasing the success of visual predation on mesopelagic resources at high light in the water column.

Microplastics in the bogue, Boops boops: A snapshot of the past from the southern Tyrrhenian Sea.

The present investigation focuses on Boops boops specimens gathered in the Gulf of Patti in 2010. Providing a snapshot from the past, this paper represents, chronologically, the first record of microplastic ingestion in the Mediterranean bogue. The plastic abundance and composition in gastrointestinal tracts of the bogue was assess, in order to improve the knowledge on spatial-temporal variability of microplastics pollution in the Mediterranean basin and in particular, in the southern Tyrrhenian Sea. In a total of 65 specimens, 180 particles of plastic (2.8 items/specimens), mainly belonging to microplastics class, were found. Fragments (63%) and fibres (30%) were the predominant shape categories. Eleven polymers were identified: polypropylene and polyethylene were the most abundant. Several synthetic polymers belonging to the class of elastomers were also observed. The study area is strongly influenced by the absence of trawl fishing activities and a low mixing level of the seabed that, together with the confluence of different watercourses and the presence of different kind of anthropic impact, including motorway, could make it a 'waste disposal site'. Finally, our results suggest the usefulness to retrieve older samples to better understand spatial-temporal changes in marine litter pollution over time.

Marine litter pollution associated with hydrothermal sites in the Aeolian archipelago (western Mediterranean Sea).

The Aeolian Archipelago, in the western Mediterranean Sea, is an active volcanic arc hosting several hydrothermal sites. This area, considered a Vulnerable Marine Ecosystem by The Food and Agriculture Organization because of its ecological importance and biodiversity value, is affected by various pressures and threats that may act as sources of marine litter. The aim of this paper was to analyse the composition and distribution of marine litter on the seafloor of this archipelago with a specific focus on the hydrothermal areas, using almost 60 h of remotely operated vehicle footage collected at depths of 15 to 411 m. Derelict fishing gear represented the main source of marine debris (71.9% of the overall litter); nevertheless, the observed mean litter density was quite low (0.57 items/100 m2) when compared with other Mediterranean areas, probably because fisheries in the area mainly use pelagic gear that has a low impact on the seabed. No differences were found in litter densities between hydrothermal and non-hydrothermal zones. The occurrence of benthic fauna impacted by debris was rarely recorded (only 10.6% of litter items showed interactions with species) and entanglement was the most commonly observed impact. However, both the density of synthetic fishing gear and its impact on habitats and species are bound to increase over time. Overall, plastics constituted most of the marine litter (79.7%). So, prevention and mitigation measures are needed in order to protect this sensitive ecosystem. To this end, the most effective strategy could be the establishment of a Marine Protected Area or a Site of Community Importance, due to the presence of habitats ("submarine structures made by leaking gases" and "reefs") listed in Annex I of the European Habitats Directive, where all fishing activities could be strictly regulated.

Growth-related trophic changes of Thunnus thynnus as evidenced by stable nitrogen isotopic values in the first dorsal spine.

The bluefin tuna, Thunnus thynnus, is a highly migratory and long-living fish at the top of the pelagic food web. As top predator, it plays a key role in the stability of marine food webs by exerting top-down control on its prey. The diet composition of bluefin tuna varies in relation to its growth, seasons and migratory patterns, making it difficult to evaluate spatial and temporal effects. This latter aspect is further complicated to be determined during the first months of life, when T. thynnus specimens have a rapid growth rate leading to changes in the trophic status. In this study, the potential collagen-related effects on δ15N and δ13C values were evaluated on the whole spine of adult tuna specimens collected in the central Mediterranean Sea. Obtained results showed non-significant differences between extracted and non-extracted collagen samples for δ15N in whole spine, allowing adopting the isotopic analysis both for annuli in the spine section of adults and for younger specimens, whose spine size does not permit the collagen extraction. Specifically, isotopic analysis of whole spine of the young of the year specimens, showed a rapid change in δ15N values with length, following an exponential model. For older specimens, δ15N values were higher and varied around a plateau, likely due to a higher specificity in the choice of prey and/or to change in the geographical location. Such variability was also mirrored in annuli of spines sections of adult tunas. As far as δ13C values are concerned, a strong collagen-related effect was evidenced, likely highlighting the influence of lipids. Consequently, δ13C analysis may be used only on adult specimens where collagen extraction is possible. This research also showed how isotopic analysis of both whole sample and sequence of annuli in the cross-section of dorsal spine might produce isotopic profiles useful to detect specific trophic dynamics along the bluefin tuna growth.

A new digestion approach for the extraction of microplastics from gastrointestinal tracts (GITs) of the common dolphinfish (Coryphaena hippurus) from the western Mediterranean Sea.

Plastic ingestion is one of the main impacts of marine litter on organisms. The occurrence of microplastics (MPs < 5 mm) in the stomachs of Mediterranean species was already reported in several studies. In this context, the present study aims to develop a new approach of digestion for the identification of MPs in the gastrointestinal tracts (GITs) of marine organisms. The new approach combines two digestion protocols, including potassium hydroxide (KOH) and nitric acid (HNO3), to remove most organic and inorganic materials. This digestion allows recording small MPs that are difficult to find via routinely stomach content analysis and also to minimize the overestimation of the phenomenon trough the control of airborne contamination. The new approach was tested on a voracious pelagic opportunistic predator, the common dolphinfish, a fishery resource exploited in several Mediterranean areas. The results showed that a large amount of ingested meso- and microplastics, such as fragments or sheets, was recorded in GITs (F = 65.5 %). The FTIR analysis on litter samples allowed to identify polyethylene, polypropylene and polystyrene as dominant constituent polymers of microplastics. These results confirmed that our novel combined digestion protocol represents a reliable approach to detect MPs in opportunistic pelagic predators.

First evidence of anticancer and antimicrobial activity in Mediterranean mesopelagic species.

Mesopelagic organisms form huge biomass aggregations, supporting important pelagic trophic webs and several top predators. Although some studies on the occurrence, biology and ecology of these organisms are available, to date there are no investigations on their potential use for anticancer and antimicrobial biotechnological applications. The aim of this study was to screen extracts of seven mesopelagic species for possible anticancer (Lung cell line A549, skin cell line A2058, liver cell line HepG2, breast cell line MCF7 and pancreas cell line MiaPaca-2) and antibacterial (Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, the Gram-positive bacteria methicillin resistant/sensitive Staphylococcus aureus, and Mycobacterium tuberculosis) activities. Results showed that only two species were active, the lanternfish Myctophum punctatum and the Mediterranean krill Meganyctiphanes norvegica. In particular, M. punctatum showed strong activity against the A549 and MCF7 cells, while M. norvegica was more active against HepG2 cells. Regarding antibacterial assays, both species were active against methicillin resistant S. aureus. Fractionation and LC/MS dereplication of the fractions showed that the main compounds found in extracts of both species were EPA, DHA and ETA. For some of the detected compounds anticancer and/or antibacterial activity are already known, but this is the first time that such activities have been found for mesopelagic species.

Characterization of seafloor litter on Mediterranean shallow coastal waters: Evidence from Dive Against Debris®, a citizen science monitoring approach.

Citizen science programs carried out by volunteers are fundamental for the collection of scientific data on a wide spatial scale. From 2011 to 2018, 468 survey dives were conducted in 172 coastal locations of the Mediterranean Sea through Project AWARE's citizen science program, Dive Against Debris®. During the dives, information was collected on quantity, typology and distribution of seafloor litter in shallow coastal waters. Overall, the observed average density was 43.55 items/100 m2 and plastic was largely the dominant material (55% of the total collected items) on basin scale. The most abundant seafloor litter items were plastic fragments with 9.46%, followed by beverage cans (7.45%). Single-use plastic items constituted 33% of the total marine litter. The results of the study can be used to inform policymakers of the European Community towards specific management action to contrast the marine litter in relation to the distribution of the recorded litter category.

Colonization of floats from submerged derelict fishing gears by four protected species of deep-sea corals and barnacles in the Strait of Messina (central Mediterranean Sea).

The distribution of floating litter in marine waters, influenced by currents and wind drag, often determines the dispersal of its encrusting fauna. In the present paper, we observed for the first time the colonization of rafting floats from abandoned, lost or derelict fishing gears (ALDFG) by the four protected deep-sea species: Errina aspera, Desmophyllum pertusum, Madrepora oculata Pachylasma giganteum. Overall, 41 floats, colonized by deep benthic species, were found stranded on the shore of the Sicilian coast of the Strait of Messina, between 2016 and 2019. Species composition, number and occurrence of colonizing organisms were analyzed. On the basis of the species composition (the association between E. aspera, P. giganteum and Megabalanus tulipiformis), the knowledge on their ecology, biogeography, path of local currents, it was possible to define that the area of origin of the most part of these fishing net floats was the Strait of Messina.

Composition and abundance of benthic marine litter in a coastal area of the central Mediterranean Sea.

Abundance and qualitative composition of benthic marine litter were investigated in a coastal area of the central Mediterranean Sea. Almost 30 km of video footage, collected by a Remotely Operated Vehicle between 5 and 30 m depth, were analyzed. Litter density ranged from 0 to 0.64 items/m2 with a mean of 0.11 (±0.16) items/m2. General wastes, made up almost entirely of plastic objects, were the dominant sources of debris representing 68% of the overall litter. The remaining 32% consisted of lost or abandoned fishing gears. Synthetic polymers, considering both fishing gears and general waste, represented 73% of total debris items. Our results are comparable with litter amounts reported in other Mediterranean sites at similar depths. Overall, the results are discussed in terms of monitoring strategy, to support the implementation of the Marine Strategy Framework Directive (2008/56/EC) for descriptor 10 and the Mediterranean UN Environment (UNEP/MAP) regional Plan on Marine Litter.

Bioindicators for monitoring marine litter ingestion and its impacts on Mediterranean biodiversity.

The Mediterranean Sea has been described as one of the most affected areas by marine litter in the world. Although effects on organisms from marine plastic litter ingestion have been investigated in several oceanic areas, there is still a lack of information from the Mediterranean Sea. The main objectives of this paper are to review current knowledge on the impact of marine litter on Mediterranean biodiversity, to define selection criteria for choosing marine organisms suitable for use as bioindicator species, and to propose a methodological approach to assessing the harm related to marine litter ingestion in several Mediterranean habitats and sub-regions. A new integrated monitoring tool that would provide the information necessary to design and implement future mitigation actions in the Mediterranean basin is proposed. According to bibliographic research and statistical analysis on current knowledge of marine litter ingestion, the area of the Mediterranean most studied, in terms of number of species and papers in the Mediterranean Sea is the western sub-area as well as demersal (32.9%) and pelagic (27.7%) amongst habitats. Applying ecological and biological criteria to the most threatened species obtained by statistical analysis, bioindicator species for different habitats and monitoring scale were selected. A threefold approach, simultaneously measuring the presence and effects of plastic, can provide the actual harm and sub-lethal effects to organisms caused by marine litter ingestion. The research revealed gaps in knowledge, and this paper suggests measures to close the gap. This and the selection of appropriate bioindicator species would represent a step forward for marine litter risk assessment, and the implementation of future actions and mitigation measures for specific Mediterranean areas, habitats and species affected by marine litter ingestion.

Marine litter in an EBSA (Ecologically or Biologically Significant Area) of the central Mediterranean Sea: Abundance, composition, impact on benthic species and basis for monitoring entanglement.

Marine litter is commonly observed everywhere in the ocean. In this study, we analyzed 17 km of video footage, collected by a Remotely Operated Vehicle (ROV) at depths ranging between 20 and 220 m, during 19 transects performed on the rocky banks of the Straits of Sicily. Recently, the Contracting Parties of the Convention on Biological Diversity (CBD) recognized this site as an Ecologically or Biologically Significant Area (EBSA). The research aim was to quantify the abundance of marine litter and its impact on benthic fauna. Litter density ranged from 0 items/100 m2 to 14.02 items/100 m2 with a mean (±standard error) of 2.13 (±0.84) items/100 m2. The observed average density was higher (5.2 items/100 m2) at depths >100 m than at shallower depths (<100 m, 0.71 items/100 m2). Lost or abandoned fishing lines contributed to 98.07% of the overall litter density, then representing the dominant source of marine debris. Litter interactions with fauna were frequently observed, with 30% of litter causing "entanglement/coverage" and 15% causing damage to sessile fauna. A total of 16 species showed interaction (entanglement/coverage or damage) with litter items and 12 of these are species of conservation concern according to international directives and agreements (CITES, Berne Convention, Habitat Directive, SPA/BD Protocol, IUCN Red List); we also observed 7 priority habitats of the SPA/BD Protocol. This research will support the implementation of monitoring "Harm" as recommended by the UN Environment/MAP Regional Plan on Marine Litter Management in the Mediterranean, and the Marine Strategy Framework Directive (MSFD). The institution of a SPAMI in the investigated area could represent a good management action for the protection of this hotspot of biodiversity and to achieve a Good Environmental Status (GES) for the marine environment by 2020, under the MSFD.

Exceptional discovery of a shallow-water hydrothermal site in the SW area of Basiluzzo islet (Aeolian archipelago, South Tyrrhenian Sea): An environment to preserve.

The geological, biological and geochemical features of a particular field of hydrothermal vents, discovered in the Panarea Volcanic Complex during a research survey carried out in 2015, are described for the first time. The site, located at 70-80 m depth off the South-western coast of the islet of Basiluzzo, was named Smoking Land for the presence of a large number of wide and high active chimneys and was characterized in terms of dissolved benthic fluxes, associated macrofauna and megafauna communities and preliminary mineralogy and geochemistry of chimney structures. On the whole field, a total of 39 chimneys, different in size and shape, were closely observed and described; 14 of them showed emission of low temperature hydrothermal fluids of marine origin characterized by acidified chemical conditions. The CTD and benthic chamber measurements highlighted that the Smoking Land is able to form a sea water bottom layer characterized by variable acidity and high DIC and trace elements concentrations; these characteristics weaken moving away from the chimney mouths. The SEM-EDS analysis of the collected solid samples revealed a chimney structure principally composed by amorphous and low crystalline Fe-oxyhydroxides of hydrothermal origins. The ROV explorations revealed a wide coverage of red algae (Peyssonnelia spp.) colonized by the green algae Flabiella petiolata and by suspension feeders, mainly sponges, but also bryozoans, and tubicolous polychaetes. Although novent-exclusive species were identified, the benthic communities found in association to the chimneys included more taxa than those observed in the surrounding no-vent rocky areas. These first findings evidence a submarine dynamic habitat where geological, chemical and biological processes are intimately connected, making the Smoking Land an important site in terms of marine heritage that should be safeguarded and protected.

Are shipwrecks a real hazard for the ecosystem in the Mediterranean Sea?

The aim of the present study was to evaluate the hazard from shipwrecks on communities by a holistic approach taking into account different effects on biological communities. Multibeam and Remotely Operated Vehicles surveys recorded ecological assessment of fish and benthic species on three shipwrecks flooded during the Second World War on Maërl beds habitats in the strait of Sicily. Pollution levels of a wide range of chemicals of ecotoxicological concern were also measured in sediments and in fish species from different trophic levels. Statistical analysis evidenced significant differences among pollutant levels between both sediments and fish collected in shipwreck sites and controls. Concerning fish, significant effects due to the vessel's cargo type and flooding position are recorded. In spite of that, our results underline that shipwrecks are also a hotspots of biodiversity and a habitat for preservation strategies in marine ecosystems that need to be monitored.

Fish Distribution and Habitat Complexity on Banks of the Strait of Sicily (Central Mediterranean Sea) from Remotely-Operated Vehicle (ROV) Explorations.

The Strait of Sicily was recognized internationally as an "Ecologically or Biologically Significant Area" by the Contracting Parties of the Convention on Biological Diversity in 2014. However, basic aspects of its fish diversity are still unknown and most of the information comes from traditional trawl surveys. This paper provides the first detailed description, using a Remotely Operated Vehicle (ROV), of the composition and depth distribution of the demersal fish assemblages found on banks of the Strait of Sicily and the related habitat complexity from 35 to 240 m depth. A total of 24 families and 52 fish species were recorded and depth was consistently associated with a significant proportion of the variation of the fish assemblage. The highest species richness was observed at the shallowest depth layer (0-50 m) and significantly decreased, remaining almost constant, in deeper layers. Similarly the highest abundance was recorded at 0-50 m, where C. julis represented the most abundant species, and decreased progressively throughout the whole depth gradient. Although the factor habitat complexity explained only a small proportion of the fish assemblage variation, significant differences among different degrees of habitat complexity were observed, together with a general positive trend for species richness and abundance with increasing habitat complexity. The ROV also allowed us to observe some rare or poorly known fish species such as Scorpaenodes arenai, Hyporthodus haifensis, Myliobatis aquila, Gadella maraldi, Epinephelus caninus and Lappanella fasciata. These findings show that banks serve as reservoirs for fish abundance and biodiversity and that immediate environmental conservation and management actions represent a priority not only for Italy but also for other countries which share the same area.