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To understand the response of marine calcifying organisms under high CO2 scenarios, it is critical to study their calcification patterns in the natural environment. This paper focuses on a major calcifying phytoplankton group, the coccolithophores, through the analysis of water samples collected along a W-E Mediterranean transect during two research cruises, in April 2011 (Meteor cruise M84/3) and May 2013 (MedSeA cruise 2013). The Mediterranean Sea is a marginal sea characterized by large biogeochemical gradients. Currently, it is undergoing both warming and ocean acidification, processes which are rapidly modifying species distribution and calcification. The species Emiliania huxleyi largely dominates the total coccolithophore production in present day oceans and marine basins, including the Mediterranean Sea. A series of morphometric measurements were performed on the coccoliths of this species to estimate their mass, length and calculate a calcification index (proxy for the size-normalized calcification degree). The most abundant morphotype of E. huxleyi in the Mediterranean Sea is Type A. Coccoliths of this morphotype were additionally analyzed based on scanning electron microscopy images: four calcification varieties were quantified, according to the relationship between slit length-tube width, and the state of the central area (open or closed). The average E. huxleyi coccolith mass along the Mediterranean oceanographic transect depended strongly on both the average coccolith length and calcification index. The variability in average coccolith length and calcification index across samples reflected oscillations in the relative abundance of the calcification varieties. We also demonstrated that the distribution of the calcification varieties followed the main environmental gradients (carbonate chemistry, salinity, temperature, nutrient concentrations). Hence, shifts in the distribution of the calcification varieties and of the average E. huxleyi coccolith mass are to be expected in the Mediterranean Sea under climate change. These physiological and ecological responses will modulate the net coccolithophore calcification and, ultimately, the regional carbonate export to the seafloor. [ABSTRACT FROM AUTHOR]

A number of scientific papers in the last few years singled out the influence of environmental conditions on the spatial distribution of fish species, highlighting the need for the fisheries scientific community to investigate, besides biomass estimates, also the habitat selection of commercially important fish species. The Mediterranean Sea, although generally oligotrophic, is characterized by high habitat variability and represents an ideal study area to investigate the adaptive behavior of small pelagics under different environmental conditions. In this study the habitat selection of European anchovy Engraulis encrasicolus and European sardine Sardina pilchardus is analyzed in two areas of the Mediterranean Sea that largely differentiate in terms of environmental regimes: the Strait of Sicily and the North Aegean Sea. A number of environmental parameters were used to investigate factors influencing anchovy and sardine habitat selection. Acoustic surveys data, collected during the summer period 2002–2010, were used for this purpose. The quotient analysis was used to identify the association between high density values and environmental variables; it was applied to the entire dataset in each area in order to identify similarities or differences in the “mean” spatial behavioral pattern for each species. Principal component analysis was applied to selected environmental variables in order to identify those environmental regimes which drive each of the two ecosystems. The analysis revealed the effect of food availability along with bottom depth selection on the spatial distribution of both species. Furthermore PCA results highlighted that observed selectivity for shallower waters is mainly associated to specific environmental processes that locally increase productivity. The common trends in habitat selection of the two species, as observed in the two regions although they present marked differences in hydrodynamics, seem to be driven by the oligotrophic character of the study areas, highlighting the role of areas where the local environmental regimes meet ‘the ocean triad hypothesis’. [ABSTRACT FROM AUTHOR]

A significant challenge in Prehistory is to understand the mechanisms involved in the behavioural evolution of human groups. The degree of technological and cultural development of prehistoric groups is assessed mainly through stone tools. However, other elements can provide valuable information as well. This paper presents two bone retouchers dated to the Middle Pleistocene MIS 9 used for the shaping of lithic artefacts. Originating from Bolomor Cave (Spain) and Qesem Cave (Israel), these two bone retouchers are among the earliest of the Old World. Although the emergence of such tools might be found in the latest phases of the Acheulean, their widespread use seems to coincide with independently emergent post-Acheulean cultural complexes at both ends of the Mediterranean Sea: the post-Acheulean/pre-Mousterian of Western Europe and the Acheulo Yabrudian Cultural Complex of the Levant. Both entities seem to reflect convergent processes that may be viewed in a wider cultural context as reflecting new technology-related behavioural patterns as well as new perceptions in stone tool manufacturing. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of tow duration on catch per unit of swept area (CPUE), trawl catch performance, and the proportion of the species caught in a trawl survey. Longer tows are expected to have a greater probability of catching species. An average of 26 species were caught in the first 30 minutes, whereas only about one additional species was caught in the next 30 minutes in longer tows. The shorter tows involved a decrement in catch weight for 11 of the 12 target species sampled, demonstrating that tow duration did affect catch per unit of swept area CPUE. The shorter tows were associated with a significant reduction of the overall CPUE in terms of weight of the main target species and of the total catch (circa 60%). The same strong reduction of around 70% was found in particular for European hake (Merluccius merluccius) and surmullet (Mullus spp) and 50% for Nephrops (Nephrops norvegicus). The shorter tows were less efficient in catching large-sized hake, surmullet, Nephrops, Atlantic horse mackerel (Trachurus trachurus), and poor cod (Trisopterus minutus), even though the difference was significant only for Nephrops. Regardless of the p-value statistic, these findings suggest that the continuity of survey time series would be severely impaired by changing tow duration. Further work is required to explore a way to reduce tow duration without reducing CPUE. [ABSTRACT FROM AUTHOR]

Jellyfish blooms cause important ecological and socio-economic problems. Among jellyfish, cubozoans are infamous for their painful, sometimes deadly, stings and are a major public concern in tropical to subtropical areas; however, there is little information about the possible causes of their outbreaks. After a bloom of the cubomedusa Carybdea marsupialis (Carybdeidae) along the coast of Denia (SW Mediterranean, Spain) in 2008 with negative consequences for local tourism, the necessity to understand the ecological restrictions on medusae abundance was evident. Here we use different models (GAM and zero-inflated models) to understand the environmental and human related factors influencing the abundance and distribution of C. marsupialis along the coast of Denia. Selected variables differed among medusae size classes, showing different environmental restriction associated to the developmental stages of the species. Variables implicated with dispersion (e.g. wind and current) affected mostly small and medium size classes. Sea surface temperature, salinity and proxies of primary production (chl a, phosphates, nitrates) were related to the abundances of small and large size classes, highlighting the roles of springtime salinity changes and increased primary production that may promote and maintain high densities of this species. The increased primary (and secondary) production due to anthropogenic impact is implicated as the factor enabling high numbers of C. marsupialis to thrive. Recommendations for monitoring blooms of this species along the study area and applicable to Mediterranean Sea include focus effort in coastal waters where productivity have been enriched by anthropogenic activities. [ABSTRACT FROM AUTHOR]

Background: Marine species can demonstrate strong genetic differentiation and population structure despite the hypothesis of open seas and high connectivity. Some suggested drivers causing the genetic breaks are oceanographic barriers and the species’ biology. We assessed the relevance of seven major oceanographic fronts on species connectivity while considering their dispersal capacity and life strategy. Methods: We systematically reviewed the scientific articles reporting population genetic differentiation along the Mediterranean Sea and across the Atlantic-Mediterranean transition. We retained those considering at least one sampling locality at each side of an oceanographic front, and at least two localities with no-front between them to correctly assess the effect of the front. To estimate the impact of life history characteristics affecting connectivity we considered the planktonic larval duration (PLD) and adult life strategy. Results: Oceanographic barriers in the Mediterranean Sea seem to reduce gene flow globally; however, this effect is not homogeneous considering the life history traits of the species. The effect of the oceanographic fronts reduces gene flow in highly mobile species with PLD larger than 2–4 weeks. Benthic sessile species and/or with short PLD (< 2 weeks) have more significant genetic breaks between localities than species with higher motility; however, genetic differentiation occurs independently of the presence of a front. Conclusion: Genetic connectivity is important for populations to recover from anthropogenic or natural impacts. We show that species with low mobility, mostly habitat-formers, have high genetic differentiation but low gene flow reduction mediated by the front, therefore, considering the importance of these species, we emphasize the vulnerability of the Mediterranean ecosystems and the necessity of protection strategies based on the whole ecosystem. [ABSTRACT FROM AUTHOR]

Diplectanid monogeneans are gill parasites that can infect fish in huge numbers and thus become harmful, especially in maricultured fish. It is therefore useful to have taxonomic tools, such as keys, to identify species. The following diplectanid species from groupers of the Mediterranean Sea were studied: five species of Pseudorhabdosynochus Yamaguti, 1958, including P. riouxi (Oliver, 1986) Kritsky & Beverley-Burton, 1986 from the dusky grouper Mycteroperca marginata, P. enitsuji Neifar & Euzet, 2007, P. bouaini Neifar & Euzet, 2007, P. dolicocolpos Neifar & Euzet, 2007 and P. sinediscus Neifar & Euzet, 2007 from the goldblotch grouper M. costae, and Echinoplectanum echinophallus (Euzet & Oliver, 1965) Justine & Euzet, 2006 from the dusky grouper. New material was obtained from fish collected from off Tunisia and Libya and compared to the type-material and voucher specimens in museum collections. Identifications of fish were confirmed by barcoding of cytochrome c oxidase subunit I (COI) sequences. The sclerotized vagina was considered the most important structure for systematics. The three species P. riouxi, P. bouaini, and P. enitsuji share a common general structure of the sclerotized vagina with a conspicuous spherical secondary chamber. We thus propose the ‘Pseudorhabdosynochus riouxi group’ to accommodate them. Pseudorhabdosynochus dolicocolpos has an elongate vaginal structure that is completely different from all its congeneric species reported from the Mediterranean Sea, and Pseudorhabdosynochus sinediscus has a sclerotized vagina in which the secondary chamber is not visible, and a haptor without squamodiscs. A taxonomic key to diplectanid species on Mycteroperca spp. in the Mediterranean Sea is proposed; it includes ten species of Pseudorhabdosynochus and one species of Echinoplectanum. [ABSTRACT FROM AUTHOR]

The greater amberjack Seriola dumerili is a large teleost fish with rapid growth and excellent flesh quality, whose domestication represents an ambitious challenge for aquaculture. The occurrence of reproductive dysfunctions in greater amberjack reared in captivity was investigated by comparing reproductive development of wild and captive-reared individuals. Wild and captive-reared breeders were sampled in the Mediterranean Sea during three different phases of the reproductive cycle: early gametogenesis (EARLY, late April-early May), advanced gametogenesis (ADVANCED, late May-early June) and spawning (SPAWNING, late June-July). Fish reproductive state was evaluated using the gonado-somatic index (GSI), histological analysis of the gonads and determination of sex steroid levels in the plasma, and correlated with leptin expression in the liver and gonad biochemical composition. The GSI and sex steroid levels were lower in captive-reared than in wild fish. During the ADVANCED period, when the wild greater amberjack breeders were already in spawning condition, ovaries of captive-reared breeders showed extensive atresia of late vitellogenic oocytes and spermatogenic activity ceased in the testes of half of the examined males. During the SPAWNING period, all captive-reared fish had regressed gonads, while wild breeders still displayed reproductive activity. Liver leptin expression and gonad proximate composition of wild and captive greater amberjack were similar. However, the gonads of captive-reared fish showed different total polar lipid contents, as well as specific lipid classes and fatty acid profiles with respect to wild individuals. This study underlines the need for an improvement in rearing technology for this species, which should include minimum handling during the reproductive season and the formulation of a specific diet to overcome the observed gonadal decrements of phospholipids, DHA (22:6n-3) and ARA (20:4n-6), compared to wild breeders. [ABSTRACT FROM AUTHOR]

The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (< 2 mm) was higher within the 1-km coastal water strip, suggesting a rapid fragmentation down along the shoreline, likely related with the washing ashore on the beaches. This study constitutes a first attempt to determine the impact of plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts. [ABSTRACT FROM AUTHOR]

In this pilot study for the first time, ancient DNA has been extracted from bone remains of Salmo trutta. These samples were from a stratigraphic succession located in a coastal cave of Calabria (southern Italy) inhabited by humans from upper Palaeolithic to historical times. Seven pairs of primers were used to PCR-amplify and sequence from 128 to 410 bp of the mtDNA control region of eleven samples. Three haplotypes were observed: two (ADcs-1 and MEcs-1) already described in rivers from the Italian peninsula; one (ATcs-33) belonging to the southern Atlantic clade of the AT Salmo trutta mtDNA lineage (sensu Bernatchez). The prehistoric occurrence of this latter haplotype in the water courses of the Italian peninsula has been detected for the first time in this study. Finally, we observed a correspondence between frequency of trout remains and variation in haplotype diversity that we related with ecological and demographic changes resulting from a period of rapid cooling known as the Younger Dryas. [ABSTRACT FROM AUTHOR]

We assess the occurrence and extent of cold-water coral (CWC) species Madrepora oculata and Dendrophyllia cornigera, as well as gorgonian red coral Corallium rubrum, in La Fonera canyon head (Northwestern Mediterranean Sea), as well as human impacts taking place in their habitats. Occurrence is assessed based on Remotely Operated Vehicle (ROV) video imaging. Terrain classification techniques are applied to high-resolution swath bathymetric data to obtain semi-automatic interpretative maps to identify the relationship between coral distribution patterns and canyon environments. A total of 21 ROV immersions were carried out in different canyon environments at depths ranging between 79 and 401 m. Large, healthy colonies of M. oculata occur on abrupt, protected, often overhanging, rocky sections of the canyon walls, especially in Illa Negra branch. D. cornigera is sparser and evenly distributed at depth, on relatively low sloping areas, in rocky but also partially sedimented areas. C. rubrum is most frequent between 100 and 160 m on highly sloping rocky areas. The probable extent of CWC habitats is quantified by applying a maximum entropy model to predict habitat suitability: 0.36 km2 yield M. oculata occurrence probabilities over 70%. Similar predictive models have been produced for D. cornigera and C. rubrum. All ROV transects document either the presence of litter on the seafloor or pervasive trawling marks. Nets and longlines are imaged entangled on coral colonies. Coral rubble is observed at the foot of impacted colonies. Some colonies are partially covered by sediment that could be the result of the resuspension generated by bottom trawling on neighbouring fishing grounds, which has been demonstrated to be responsible of daily increases in sediment fluxes within the canyon. The characteristics of the CWC community in La Fonera canyon are indicative that it withstands high environmental stress of both natural and human origin. [ABSTRACT FROM AUTHOR]

Here we present, for the first time, the elemental concentration, including C, N and O, of single phytoplankton cells collected from the sea. Plankton elemental concentration and stoichiometry are key variables in phytoplankton ecophysiology and ocean biogeochemistry, and are used to link cells and ecosystems. However, most field studies rely on bulk techniques that overestimate carbon and nitrogen because the samples include organic matter other than plankton organisms. Here we used X-ray microanalysis (XRMA), a technique that, unlike bulk analyses, gives simultaneous quotas of C, N, O, Mg, Si, P, and S, in single-cell organisms that can be collected directly from the sea. We analysed the elemental composition of dinoflagellates and diatoms (largely Chaetoceros spp.) collected from different sites of the Catalan coast (NW Mediterranean Sea). As expected, a lower C content is found in our cells compared to historical values of cultured cells. Our results indicate that, except for Si and O in diatoms, the mass of all elements is not a constant fraction of cell volume but rather decreases with increasing cell volume. Also, diatoms are significantly less dense in all the measured elements, except Si, compared to dinoflagellates. The N:P ratio of both groups is higher than the Redfield ratio, as it is the N:P nutrient ratio in deep NW Mediterranean Sea waters (N:P = 20–23). The results suggest that the P requirement is highest for bacterioplankton, followed by dinoflagellates, and lowest for diatoms, giving them a clear ecological advantage in P-limited environments like the Mediterranean Sea. Finally, the P concentration of cells of the same genera but growing under different nutrient conditions was the same, suggesting that the P quota of these cells is at a critical level. Our results indicate that XRMA is an accurate technique to determine single cell elemental quotas and derived conversion factors used to understand and model ocean biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Jellyfish are of particular concern for marine finfish aquaculture. In recent years repeated mass mortality episodes of farmed fish were caused by blooms of gelatinous cnidarian stingers, as a consequence of a wide range of hemolytic, cytotoxic, and neurotoxic properties of associated cnidocytes venoms. The mauve stinger jellyfish Pelagia noctiluca (Scyphozoa) has been identified as direct causative agent for several documented fish mortality events both in Northern Europe and the Mediterranean Sea aquaculture farms. We investigated the effects of P. noctiluca envenomations on the gilthead sea bream Sparus aurata by in vivo laboratory assays. Fish were incubated for 8 hours with jellyfish at 3 different densities in 300 l experimental tanks. Gill disorders were assessed by histological analyses and histopathological scoring of samples collected at time intervals from 3 hours to 4 weeks after initial exposure. Fish gills showed different extent and severity of gill lesions according to jellyfish density and incubation time, and long after the removal of jellyfish from tanks. Jellyfish envenomation elicits local and systemic inflammation reactions, histopathology and gill cell toxicity, with severe impacts on fish health. Altogether, these results shows P. noctiluca swarms may represent a high risk for Mediterranean finfish aquaculture farms, generating significant gill damage after only a few hours of contact with farmed S. aurata. Due to the growth of the aquaculture sector and the increased frequency of jellyfish blooms in the coastal waters, negative interactions between stinging jellyfish and farmed fish are likely to increase with the potential for significant economic losses. [ABSTRACT FROM AUTHOR]

The common octopus, Octopus vulgaris Cuvier 1797, is a largely exploited cephalopod species in the Mediterranean Sea and the Atlantic Ocean, as well as along the coasts of Africa, Brazil and Japan, where its taxonomic identity is still debated. The assessment of its genetic structure is a pressing need to correctly manage the resource and to avoid overfishing and collapsing of local stocks. Here we analysed genetic variation and population structure of O. vulgaris using thirteen microsatellite loci in seven sampling localities from the Mediterranean Sea and one from the Atlantic Ocean. We also used a DNA barcoding approach by COI gene fragment to understand the phylogenetic relationships among the specimens here investigated and the ones whose sequences are available in literature. Our results reveal high levels of allelic richness and moderate heterozygosity in all samples investigated, and a pronounced differentiation of the Atlantic and Sicilian specimens. This latter aspect seems to support the isolation of the biota within the Strait of Messina. A certain degree of differentiation was detected among the other geographic samples within the Mediterranean Sea, which is more compatible with an island model than isolation by distance. The occurrence of null alleles affected more genetic diversity indices than population structure estimations. This study provides new insights about the genetic diversity and structure of O. vulgaris in the area of interest, which can be used as guidelines for a fisheries management perspective. [ABSTRACT FROM AUTHOR]

Within the framework of the EU Life+ project named LIFE09 NAT/IT/000190 ARION, a permanent automated real-time passive acoustic monitoring system for the improvement of the conservation status of the transient and resident population of bottlenose dolphin (Tursiops truncatus) has been implemented and installed in the Portofino Marine Protected Area (MPA), Ligurian Sea. The system is able to detect the simultaneous presence of dolphins and boats in the area and to give their position in real time. This information is used to prevent collisions by diffusing warning messages to all the categories involved (tourists, professional fishermen and so on). The system consists of two gps-synchronized acoustic units, based on a particular type of marine buoy (elastic beacon), deployed about 1 km off the Portofino headland. Each one is equipped with a four-hydrophone array and an onboard acquisition system which can record the typical social communication whistles emitted by the dolphins and the sound emitted by boat engines. Signals are pre-filtered, digitized and then broadcast to the ground station via wi-fi. The raw data are elaborated to get the direction of the acoustic target to each unit, and hence the position of dolphins and boats in real time by triangulation. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea and adjoining East Atlantic Ocean host a diverse array of small-sized mussels that predominantly live on sunken, decomposing organic remains. At least two of these, Idas modiolaeformis and Idas simpsoni, are known to engage in gill-associated symbioses; however, the composition, diversity and variability of these symbioses with changing habitat and location is poorly defined. The current study presents bacterial symbiont assemblage data, derived from 454 pyrosequencing carried out on replicate specimens of these two host species, collected across seven sample sites found in three oceanographic regions in the Mediterranean and East Atlantic. The presence of several bacterial OTUs in both the Mediterranean Sea and eastern Atlantic suggests that similar symbiont candidates occur on both sides of the Strait of Gibraltar. The results reveal markedly different symbiotic modes in the two species. Idas modiolaeformis displays high symbiont diversity and flexibility, with strong variation in symbiont composition from the East Mediterranean to the East Atlantic. Idas simpsoni displays low symbiont diversity but high symbiont fidelity, with a single dominant OTU occurring in all specimens analysed. These differences are argued to be a function of the host species, where subtle differences in host evolution, life-history and behaviour could partially explain the observed patterns. The variability in symbiont compositions, particularly in Idas modiolaeformis, is thought to be a function of the nature, context and location of the habitat from which symbiont candidates are sourced. [ABSTRACT FROM AUTHOR]

Some of the most important effects of global change on coastal marine systems include increasing nutrient inputs and higher levels of ultraviolet radiation (UVR, 280–400 nm), which could affect primary producers, a key trophic link to the functioning of marine food webs. However, interactive effects of both factors on the phytoplankton community have not been assessed for the Mediterranean Sea. An in situ factorial experiment, with two levels of ultraviolet solar radiation (UVR+PAR vs. PAR) and nutrients (control vs. P-enriched), was performed to evaluate single and UVR×P effects on metabolic, enzymatic, stoichiometric and structural phytoplanktonic variables. While most phytoplankton variables were not affected by UVR, dissolved phosphatase (APAEX) and algal P content increased in the presence of UVR, which was interpreted as an acclimation mechanism of algae to oligotrophic marine waters. Synergistic UVR×P interactive effects were positive on photosynthetic variables (i.e., maximal electron transport rate, ETRmax), but negative on primary production and phytoplankton biomass because the pulse of P unmasked the inhibitory effect of UVR. This unmasking effect might be related to greater photodamage caused by an excess of electron flux after a P pulse (higher ETRmax) without an efficient release of carbon as the mechanism to dissipate the reducing power of photosynthetic electron transport. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise. [ABSTRACT FROM AUTHOR]

The giant devil ray Mobula mobular, the only Mediterranean mobulid, is subject to mortality caused by directed and accidental captures in fisheries throughout the region. Whilst the combination of human impacts, limited range and a low reproductive potential is not inconsistent with its endangered listing, there are insufficient data to enable a quantitative assessment of trends. Without this, it is difficult to assess and prioritise threats and develop effective conservation actions. Using results from aerial surveys conducted between 2009 and 2014 over the Ligurian, Corsican, Sardinian, northern and central Tyrrhenian seas (626,228 km2), this study provides the first quantitative information on giant devil ray abundance and habitat choice in the western Mediterranean. Devil rays were observed in all seasons except winter, with their estimated abundance in the study area peaking in summer. The overall uncorrected mean density in the study area during summer was estimated at 0.0257 individuals km-2 (range: 0.017–0.044), resulting in a total abundance estimate of 6,092 (12.7%CV) individuals at the surface; once corrected for availability bias, this estimate indicates a summer presence of >12,700 devil rays in the study area. Rays were mostly observed alone even if occasionally, larger aggregations up to a maximum of 18 individuals were observed. Although observed throughout the study area, spatial modelling identified their preferred habitat to be over a broad strip connecting the Tuscan Archipelago to Eastern Sardinia, over a wide range of water depths ranging from 10 to 2000m. The observed seasonal changes in giant devil ray distribution in this study, combined with similar evidence from other areas in the Mediterranean, support the hypothesis that the species undertakes latitudinal migrations across the region, taking advantage of highly productive waters in the north during summer, and warmer southern waters during winter. [ABSTRACT FROM AUTHOR]

The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species Caryophyllia inornata. Cytometric analyses were used to define the annual development of germ cells and embryogenesis. The species was gonochoric with three times more male polyps than female. Polyps were sexually mature from 6 to 8 mm length. Not only females, but also sexually inactive individuals (without germ cells) and males were found to brood their embryos. Spermaries required 12 months to reach maturity, while oogenesis seemed to occur more rapidly (5–6 months). Female polyps were found only during spring and summer. Furthermore, the rate of gamete development in both females and males increased significantly from March to May and fertilization was estimated to occur from April to July, when mature germ cells disappeared. Gametogenesis showed a strong seasonal influence, while embryos were found throughout the year in males and in sexually inactive individuals without a defined trend. This unusual embryogenesis suggests the possibility of agamic reproduction, which combined with sexual reproduction results in high fertility. This mechanism is uncommon and only four other scleractinians (Pocillopora damicornis, Tubastraea diaphana, T. coccinea and Oulastrea crispata) have been shown to generate their broods asexually. The precise nature of this process is still unknown. [ABSTRACT FROM AUTHOR]

This study considers variability in phytoplankton and heterotrophic bacterial abundances and production rates, in one of the most oligotrophic marine regions in the world–the Levantine Basin. The temporal dynamics of these planktonic groups were studied in the coastal waters of the southeastern Mediterranean Sea approximately every two weeks for a total of two years. Heterotrophic bacteria were abundant mostly during late summer and midwinter, and were positively correlated with bacterial production and with N2 fixation. Based on size fractionating, picophytoplankton was abundant during the summer, whereas nano-microphytoplankton predominated during the winter and early spring, which were also evident in the size-fractionated primary production rates. Autotrophic abundance and production correlated negatively with temperature, but did not correlate with inorganic nutrients. Furthermore, a comparison of our results with results from the open Levantine Basin demonstrates that autotrophic and heterotrophic production, as well as N2 fixation rates, are considerably higher in the coastal habitat than in the open sea, while nutrient levels or cell abundance are not different. These findings have important ecological implications for food web dynamics and for biological carbon sequestration in this understudied region. [ABSTRACT FROM AUTHOR]

Different dolphin and tuna species have frequently been reported to aggregate in areas of high frontal activity, sometimes developing close multi-species associations to increase feeding success. Aerial surveys are a common tool to monitor the density and abundance of marine mammals, and have recently become a focus in the search for methods to provide fisheries-independent abundance indicators for tuna stock assessment. In this study, we present first density estimates corrected for availability bias of fin whales (Balaenoptera physalus) and striped dolphins (Stenella coeruleoalba) from the Golf of Lions (GoL), compared with uncorrected estimates of Atlantic bluefin tuna (ABFT; Thunnus thynnus) densities from 8 years of line transect aerial surveys. The raw sighting data were further used to analyze patterns of spatial co-occurrence and density of these three top marine predators in this important feeding ground in the Northwestern Mediterranean Sea. These patterns were investigated regarding known species-specific feeding preferences and environmental characteristics (i. e. mesoscale activity) of the survey zone. ABFT was by far the most abundant species during the surveys in terms of schools and individuals, followed by striped dolphins and fin whales. However, when accounted for availability bias, schools of dolphins and fin whales were of equal density. Direct interactions of the species appeared to be the exception, but results indicate that densities, presence and core sighting locations of striped dolphins and ABFT were correlated. Core sighting areas of these species were located close to an area of high mesoscale activity (oceanic fronts and eddies). Fin whales did not show such a correlation. The results further highlight the feasibility to coordinate research efforts to explore the behaviour and abundance of the investigated species, as demanded by the Marine Strategy Framework Directive (MSFD). [ABSTRACT FROM AUTHOR]

Recent findings have shown that photosynthesis in the skin of the seed of Posidonia oceanica enhances seedling growth. The seagrass genus Posidonia is found only in two distant parts of the world, the Mediterranean Sea and southern Australia. This fact led us to question whether the acquisition of this novel mechanism in the evolution of this seagrass was a pre-adaptation prior to geological isolation of the Mediterranean from Tethys Sea in the Eocene. Photosynthetic activity in seeds of Australian species of Posidonia is still unknown. This study shows oxygen production and respiration rates, and maximum PSII photochemical efficiency (Fv : Fm) in seeds of two Australian Posidonia species (P. australis and P. sinuosa), and compares these with previous results for P. oceanica. Results showed relatively high oxygen production and respiratory rates in all three species but with significant differences among them, suggesting the existence of an adaptive mechanism to compensate for the relatively high oxygen demands of the seeds. In all cases maximal photochemical efficiency of photosystem II rates reached similar values. The existence of photosynthetic activity in the seeds of all three species implicates that it was an ability probably acquired from a common ancestor during the Late Eocene, when this adaptive strategy could have helped Posidonia species to survive in nutrient-poor temperate seas. This study sheds new light on some aspects of the evolution of marine plants and represents an important contribution to global knowledge of the paleogeographic patterns of seagrass distribution. [ABSTRACT FROM AUTHOR]

Massive outbreaks are increasing all over the world, which are likely related to climate change. The North Adriatic Sea, a sub-basin of the Mediterranean Sea, is a shallow semi-closed sea receiving high nutrients inputs from important rivers. These inputs sustain the highest productive basin of the Mediterranean Sea. Moreover, this area shows a high number of endemisms probably due to the high diversity of environmental conditions and the conspicuous food availability. Here, we documented two massive mortalities (2009 and 2011) and the pattern of recovery of the affected biocoenoses in the next two years. Results show an impressive and fast shift of the benthic assemblage from a biocoenosis mainly composed of slow-growing and long-lived species to a biocoenosis dominated by fast-growing and short-lived species. The sponge Chondrosia reniformis, one of the key species of this assemblage, which had never been involved in previous massive mortality events in the Mediterranean Sea, reduced its coverage by 70%, and only few small specimens survived. All the damaged sponges, together with many associated organisms, were detached by rough-sea conditions, leaving large bare areas on the rocky wall. Almost three years after the disease, the survived specimens of C. reniformis did not increase significantly in size, while the bare areas were colonized by fast-growing species such as stoloniferans, hydrozoans, mussels, algae, serpulids and bryozoans. Cnidarians were more resilient than massive sponges since they quickly recovered in less than one month. In the study area, the last two outbreaks caused a reduction in the filtration efficiency of the local benthic assemblage by over 60%. The analysis of the times series of wave heights and temperature revealed that the conditions in summer 2011 were not so extreme as to justify severe mass mortality, suggesting the occurrence of other factors which triggered the disease. The long-term observations of a benthic assemblage in the NW Adriatic Sea allowed us to monitor its dynamics before, during and after the mortality event. The N Adriatic Sea responds quickly to climatic anomalies and other environmental stresses because of the reduced dimension of the basin. The long-term consequences of frequent mass mortality episodes in this area could promote the shift from biocoenoses dominated by slow-growing and long-lived species to assemblages dominated by plastic and short life cycle species. [ABSTRACT FROM AUTHOR]

The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (<40 m), data were collected on the populations’ upper depth limit, density, colony height, and extent of injury. A three-level hierarchical sampling design was applied to assess the existence of spatial patterns, using: a) regions (located thousands of km apart), b) localities within regions (tens to hundreds of km apart), and c) sites within localities (hundreds of m to a few km apart). In the NW Mediterranean and CE Adriatic, the upper distribution limit was at depths ≤15 m, whereas in the N Aegean most populations were found deeper than 30 m. Population density ranged between 4.46-62 colonies per m2, while mean colony height was 15.6±8.9 SD cm with a maximum of 62 cm. The NW Mediterranean sites were characterized by dense populations dominated by small colonies (<20 cm), periodic recruitment, and low proportion of large gorgonians (>30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale. [ABSTRACT FROM AUTHOR]

Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. [ABSTRACT FROM AUTHOR]

Knowledge of the link between ocean hydrodynamics and distribution of small pelagic fish species is fundamental for the sustainable management of fishery resources. Both commercial and scientific communities are indeed seeking to provide services that could “connect the dots” among in situ and remote observations, numerical ocean modelling, and fisheries. In the Mediterranean Sea and, in particular, in the Sicily Channel the reproductive strategy of the European Anchovy (Engraulis encrasicolus) is strongly influenced by the oceanographic patterns, which are often visible in sea surface temperature satellite data. Based on these experimental evidences, we propose here a more general approach where the role of ocean currents, wind effects, and mesoscale activity are tied together. To investigate how these features affect anchovy larvae distribution, we pair ichthyoplankton observations to a wide remote sensing data set, and to Lagrangian numerical simulations for larval transport. Our analysis shows that while the wind-induced coastal current is able to transport anchovy larvae from spawning areas to the recruiting area off the Sicilian south-eastern tip, significant cross-shore transport due to the combination of strong northwesterly mistral winds and topographic effects delivers larvae away from the coastal conveyor belt. We then use a potential vorticity approach to describe the occurrence of larvae cross-shore transport. We conclude that monitoring and quantifying the upwelling on the southern Sicilian coast during the spawning season allows to estimate the cross-shore transport of larvae and the consequent decrease of individuals within the recruiting area. [ABSTRACT FROM AUTHOR]

Leiopathes glaberrima is a tall arborescent black coral species structuring important facies of the deep-sea rocky bottoms of the Mediterranean Sea that are severely stifled by fishing activities. At present, however, no morphological in vivo description, ecological characterization, age dating and evaluation of the possible conservation actions have ever been made for any population of this species in the basin. A dense coral population was reported during two Remotely Operated Vehicle (ROV) surveys conducted on a rocky bank off the SW coasts of Sardinia (Western Mediterranean Sea). L. glaberrima forms up to 2 m-tall colonies with a maximal observed basal diameter of nearly 7 cm. The radiocarbon dating carried out on a colony from this site with a 4 cm basal diameter revealed an approximately age of 2000 years. Considering the size-frequency distribution of the colonies in the area it is possible to hypothesize the existence of other millennial specimens occupying a supposedly very stable ecosystem. The persistence of this ecosystem is likely guaranteed by the heterogeneous rocky substrate hosting the black coral population that represents a physical barrier against the mechanical impacts acted on the surrounding muddy areas, heavily exploited as trawling fishing grounds. This favorable condition, together with the existence of a nursery area for catsharks within the coral ramifications and the occurrence of a meadow of the now rare soft bottom alcyonacean Isidella elongata in small surviving muddy enclaves, indicates that this ecosystem have to be considered a pristine Mediterranean deep-sea coral sanctuary that would deserve special protection. [ABSTRACT FROM AUTHOR]

Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes) and larger (i.e. macroplankton) organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available). Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche) weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model) characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally. [ABSTRACT FROM AUTHOR]

The identification of nursery grounds and other essential fish habitats of exploited stocks is a key requirement for the development of spatial conservation planning aimed at reducing the adverse impact of fishing on the exploited populations and ecosystems. The reduction in juvenile mortality is particularly relevant in the Mediterranean and is considered as one of the main prerequisites for the future sustainability of trawl fisheries. The distribution of nursery areas of 11 important commercial species of demersal fish and shellfish was analysed in the European Union Mediterranean waters using time series of bottom trawl survey data with the aim of identifying the most persistent recruitment areas. A high interspecific spatial overlap between nursery areas was mainly found along the shelf break of many different sectors of the Northern Mediterranean indicating a high potential for the implementation of conservation measures. Overlap of the nursery grounds with existing spatial fisheries management measures and trawl fisheries restricted areas was also investigated. Spatial analyses revealed considerable variation depending on species and associated habitat/depth preferences with increased protection seen in coastal nurseries and minimal protection seen for deeper nurseries (e.g. Parapenaeus longirostris 6%). This is partly attributed to existing environmental policy instruments (e.g. Habitats Directive and Mediterranean Regulation EC 1967/2006) aiming at minimising impacts on coastal priority habitats such as seagrass, coralligenous and maerl beds. The new knowledge on the distribution and persistence of demersal nurseries provided in this study can support the application of spatial conservation measures, such as the designation of no-take Marine Protected Areas in EU Mediterranean waters and their inclusion in a conservation network. The establishment of no-take zones will be consistent with the objectives of the Common Fisheries Policy applying the ecosystem approach to fisheries management and with the requirements of the Marine Strategy Framework Directive to maintain or achieve seafloor integrity and good environmental status. [ABSTRACT FROM AUTHOR]

We investigate long-term changes in the Mediterranean marine resources driving the trawl fisheries by analysing fishers’ perceptions (Traditional Ecological Knowledge, TEK) throughout the Mediterranean Sea during the last 80 years. To this end, we conducted an extended set of interviews with experienced fishers that enabled us to classify species (or taxa) as ‘decreasing’ or ‘increasing’ both in terms of abundance, as well as average size in the catch. The aspect that most clearly emerged in all the investigated areas over time was the notable increase of fishing capacity indicators, such as engine power and fishing depth range. Atlantic mackerel, poor cod, scorpionfishes, striped seabream, and John Dory demonstrated a decreasing trend in the fishers’ perceived abundance, while Mediterranean parrotfish, common pandora, cuttlefish, blue and red shrimp, and mullets gave indications of an increasing temporal trend. Although, as a rule, trawler captains did not report any cataclysmic changes (e.g. extinctions), when they were invited to estimate total catches, a clear decreasing pattern emerged; this being a notable finding taking into account the steep escalation of fishing efficiency during the past century. The overall deteriorating status of stocks in most Mediterranean regions calls for responsible management and design of rebuilding plans. This should include historical information accounting for past exploitation patterns that could help defining a baseline of fish abundance prior to heavy industrial fisheries exploitation. [ABSTRACT FROM AUTHOR]

We analyzed the movements of Atlantic tuna (Thunnus thynnus L.) in the Mediterranean Sea using data from 2 archival tags and 37 pop-up satellite archival tags (PAT). Bluefin tuna ranging in size from 12 to 248 kg were tagged on board recreational boats in the western Mediterranean and the Adriatic Sea between May and September during two different periods (2000 to 2001 and 2008 to 2012). Although tuna migrations between the Mediterranean Sea and the Atlantic Ocean have been well reported, our results indicate that part of the bluefin tuna population remains in the Mediterranean basin for much of the year, revealing a more complex population structure. In this study we demonstrate links between the western Mediterranean, the Adriatic and the Gulf of Sidra (Libya) using over 4336 recorded days of location and behavior data from tagged bluefin tuna with a maximum track length of 394 days. We described the oceanographic preferences and horizontal behaviors during the spawning season for 4 adult bluefin tuna. We also analyzed the time series data that reveals the vertical behavior of one pop-up satellite tag recovered, which was attached to a 43.9 kg tuna. This fish displayed a unique diving pattern within 16 days of the spawning season, suggesting a use of the thermocline as a thermoregulatory mechanism compatible with spawning. The results obtained hereby confirm that the Mediterranean is clearly an important habitat for this species, not only as spawning ground, but also as an overwintering foraging ground. [ABSTRACT FROM AUTHOR]

Marine viruses (phages) alter bacterial diversity and evolution with impacts on marine biogeochemical cycles, and yet few well-developed model systems limit opportunities for hypothesis testing. Here we isolate phage B8b from the Mediterranean Sea using Pseudoalteromonas sp. QC-44 as a host and characterize it using myriad techniques. Morphologically, phage B8b was classified as a member of the Siphoviridae family. One-step growth analyses showed that this siphovirus had a latent period of 70 min and released 172 new viral particles per cell. Host range analysis against 89 bacterial host strains revealed that phage B8b infected 3 Pseudoalteromonas strains (52 tested, >99.9% 16S rRNA gene nucleotide identity) and 1 non-Pseudoaltermonas strain belonging to Alteromonas sp. (37 strains from 6 genera tested), which helps bound the phylogenetic distance possible in a phage-mediated horizontal gene transfer event. The Pseudoalteromonas phage B8b genome size was 42.7 kb, with clear structural and replication modules where the former were delineated leveraging identification of 16 structural genes by virion structural proteomics, only 4 of which had any similarity to known structural proteins. In nature, this phage was common in coastal marine environments in both photic and aphotic layers (found in 26.5% of available viral metagenomes), but not abundant in any sample (average per sample abundance was 0.65% of the reads). Together these data improve our understanding of siphoviruses in nature, and provide foundational information for a new ‘rare virosphere’ phage–host model system. [ABSTRACT FROM AUTHOR]

Ecoregionalization of the ocean is a necessary step for spatial management of marine resources. Previous ecoregionalization efforts were based either on the distribution of species or on the distribution of physical and biogeochemical properties. These approaches ignore the dispersal of species by oceanic circulation that can connect regions and isolates others. This dispersal effect can be quantified through connectivity that is the probability, or time of transport between distinct regions. Here a new regionalization method based on a connectivity approach is described and applied to the Mediterranean Sea. This method is based on an ensemble of Lagrangian particle numerical simulations using ocean model outputs at 1/12° resolution. The domain is divided into square subregions of 50 km size. Then particle trajectories are used to quantify the oceanographic distance between each subregions, here defined as the mean connection time. Finally the oceanographic distance matrix is used as a basis for a hierarchical clustering. 22 regions are retained and discussed together with a quantification of the stability of boundaries between regions. Identified regions are generally consistent with the general circulation with boundaries located along current jets or surrounding gyres patterns. Regions are discussed in the light of existing ecoregionalizations and available knowledge on plankton distributions. This objective method complements static regionalization approaches based on the environmental niche concept and can be applied to any oceanic region at any scale. [ABSTRACT FROM AUTHOR]

Understanding the ecological and anthropogenic drivers of population dynamics requires detailed studies on habitat selection and spatial distribution. Although small pelagic fish aggregate in large shoals and usually exhibit important spatial structure, their dynamics in time and space remain unpredictable and challenging. In the Gulf of Lions (north-western Mediterranean), sardine and anchovy biomasses have declined over the past 5 years causing an important fishery crisis while sprat abundance rose. Applying geostatistical tools on scientific acoustic surveys conducted in the Gulf of Lions, we investigated anchovy, sardine and sprat spatial distributions and structures over 10 years. Our results show that sardines and sprats were more coastal than anchovies. The spatial structure of the three species was fairly stable over time according to variogram outputs, while year-to-year variations in kriged maps highlighted substantial changes in their location. Support for the McCall's basin hypothesis (covariation of both population density and presence area with biomass) was found only in sprats, the most variable of the three species. An innovative method to investigate species collocation at different scales revealed that globally the three species strongly overlap. Although species often co-occurred in terms of presence/absence, their biomass density differed at local scale, suggesting potential interspecific avoidance or different sensitivity to local environmental characteristics. Persistent favourable areas were finally detected, but their environmental characteristics remain to be determined. [ABSTRACT FROM AUTHOR]

The Mediterranean and Black Seas are semi-enclosed basins characterized by high environmental variability and growing anthropogenic pressure. This has led to an increasing need for a bioregionalization of the oceanic environment at local and regional scales that can be used for managerial applications as a geographical reference. We aim to identify biogeochemical subprovinces within this domain, and develop synthetic indices of the key oceanographic dynamics of each subprovince to quantify baselines from which to assess variability and change. To do this, we compile a data set of 101 months (2002–2010) of a variety of both “classical” (i.e., sea surface temperature, surface chlorophyll-a, and bathymetry) and “mesoscale” (i.e., eddy kinetic energy, finite-size Lyapunov exponents, and surface frontal gradients) ocean features that we use to characterize the surface ocean variability. We employ a k-means clustering algorithm to objectively define biogeochemical subprovinces based on classical features, and, for the first time, on mesoscale features, and on a combination of both classical and mesoscale features. Principal components analysis is then performed on the oceanographic variables to define integrative indices to monitor the environmental changes within each resultant subprovince at monthly resolutions. Using both the classical and mesoscale features, we find five biogeochemical subprovinces for the Mediterranean and Black Seas. Interestingly, the use of mesoscale variables contributes highly in the delineation of the open ocean. The first axis of the principal component analysis is explained primarily by classical ocean features and the second axis is explained by mesoscale features. Biogeochemical subprovinces identified by the present study can be useful within the European management framework as an objective geographical framework of the Mediterranean and Black Seas, and the synthetic ocean indicators developed here can be used to monitor variability and long-term change. [ABSTRACT FROM AUTHOR]

The surface waters of the Mediterranean Sea are extremely poor in the nutrients necessary for plankton growth. At the same time, the Mediterranean Sea borders with the largest and most active desert areas in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. We describe statistical correlations between dust deposition over the Mediterranean Sea and surface chlorophyll concentrations at ecological time scales. Aerosol deposition of Saharan origin may explain 1 to 10% (average 5%) of seasonally detrended chlorophyll variability in the low nutrient-low chlorophyll Mediterranean. Most of the statistically significant correlations are positive with main effects in spring over the Eastern and Central Mediterranean, conforming to a view of dust events fueling needed nutrients to the planktonic community. Some areas show negative effects of dust deposition on chlorophyll, coinciding with regions under a large influence of aerosols from European origin. The influence of dust deposition on chlorophyll dynamics may become larger in future scenarios of increased aridity and shallowing of the mixed layer. [ABSTRACT FROM AUTHOR]

The large-scale deep-sea biodiversity distribution of the benthic fauna was explored in the Mediterranean Sea, which can be seen as a miniature model of the oceans of the world. Within the framework of the BIOFUN project (“Biodiversity and Ecosystem Functioning in Contrasting Southern European Deep-sea Environments: from viruses to megafauna”), we investigated the large spatial scale variability (over >1,000 km) of the bathyal macrofauna communities that inhabit the Mediterranean basin, and their relationships with the environmental variables. The macrofauna abundance, biomass, community structure and functional diversity were analysed and the α-diversity and β-diversity were estimated across six selected slope areas at different longitudes and along three main depths. The macrobenthic standing stock and α-diversity were lower in the deep-sea sediments of the eastern Mediterranean basin, compared to the western and central basins. The macrofaunal standing stock and diversity decreased significantly from the upper bathyal to the lower bathyal slope stations. The major changes in the community composition of the higher taxa and in the trophic (functional) structure occurred at different longitudes, rather than at increasing water depth. For the β-diversity, very high dissimilarities emerged at all levels: (i) between basins; (ii) between slopes within the same basin; and (iii) between stations at different depths; this therefore demonstrates the high macrofaunal diversity of the Mediterranean basins at large spatial scales. Overall, the food sources (i.e., quantity and quality) that characterised the west, central and eastern Mediterranean basins, as well as sediment grain size, appear to influence the macrobenthic standing stock and the biodiversity along the different slope areas. [ABSTRACT FROM AUTHOR]

Background: DNA barcoding enhances the prospects for species-level identifications globally using a standardized and authenticated DNA-based approach. Reference libraries comprising validated DNA barcodes (COI) constitute robust datasets for testing query sequences, providing considerable utility to identify marine fish and other organisms. Here we test the feasibility of using DNA barcoding to assign species to tissue samples from fish collected in the central Mediterranean Sea, a major contributor to the European marine ichthyofaunal diversity. Methodology/Principal Findings: A dataset of 1278 DNA barcodes, representing 218 marine fish species, was used to test the utility of DNA barcodes to assign species from query sequences. We tested query sequences against 1) a reference library of ranked DNA barcodes from the neighbouring North East Atlantic, and 2) the public databases BOLD and GenBank. In the first case, a reference library comprising DNA barcodes with reliability grades for 146 fish species was used as diagnostic dataset to screen 486 query DNA sequences from fish specimens collected in the central basin of the Mediterranean Sea. Of all query sequences suitable for comparisons 98% were unambiguously confirmed through complete match with reference DNA barcodes. In the second case, it was possible to assign species to 83% (BOLD-IDS) and 72% (GenBank) of the sequences from the Mediterranean. Relatively high intraspecific genetic distances were found in 7 species (2.2%–18.74%), most of them of high commercial relevance, suggesting possible cryptic species. Conclusion/Significance: We emphasize the discriminatory power of COI barcodes and their application to cases requiring species level resolution starting from query sequences. Results highlight the value of public reference libraries of reliability grade-annotated DNA barcodes, to identify species from different geographical origins. The ability to assign species with high precision from DNA samples of disparate quality and origin has major utility in several fields, from fisheries and conservation programs to control of fish products authenticity. [ABSTRACT FROM AUTHOR]

This study is aimed at assessing the effects of multiple stressors (thermal shock, fishing capture, and exposure to air) on the benthic stomatopod Squilla mantis, a burrowing crustacean quite widespread in the Mediterranean Sea. Laboratory analyses were carried out to explore the physiological impairment onset over time, based on emersion and thermal shocks, on farmed individuals. Parallel field-based studies were carried out to also investigate the role of fishing (i.e., otter trawling) in inducing physiological imbalance in different seasonal conditions. The dynamics of physiological recovery from physiological disruption were also studied. Physiological stress was assessed by analysing hemolymph metabolites (L-Lactate, D-glucose, ammonia, and H+), as well as glycogen concentration in muscle tissues. The experiments were carried out according to a factorial scheme considering the three factors (thermal shock, fishing capture, and exposure to air) at two fixed levels in order to explore possible synergistic, additive, or antagonistic effects among factors. Additive effects on physiological parameters were mainly detected when the three factors interacted together while synergistic effects were found as effect of the combination of two factors. This finding highlights that the physiological adaptive and maladaptive processes induced by the stressors result in a dynamic response that may encounter physiological limits when high stress levels are sustained. Thus, a further increase in the physiological parameters due to synergies cannot be reached. Moreover, when critical limits are encountered, mortality occurs and physiological parameters reflect the response of the last survivors. In the light of our mortality studies, thermal shock and exposure to air have the main effect on the survival of S. mantis only on trawled individuals, while lab-farmed individuals did not show any mortality during exposure to air until after 2 hours. [ABSTRACT FROM AUTHOR]

Deep-sea bivalves of the Xylophagaidae, a poorly known group, are obligate wood-borers. Deployment of wood in three submarine canyons off the Iberian coast, the Blanes and La Fonera Canyons (Mediterranean Sea) and the Avilés Canyon (Cantabric Sea, Bay of Biscay), lead to the discovery of four xylophagaid species in our samples. Xylophaga dorsalis (the dominant species), X. atlantica, X. cf. anselli and the new species X. brava, were identified on the basis of morphological data, and supported by a phylogenetic reconstruction based on the nuclear genes 18S rDNA and 28S rDNA and including several genus of Xylophagaidae. Genetic divergence between species of Xylophaga varied between genes, ranging from 0.5 to 4.0% for the 18SrDNA and from 4.1 to 16.6% for the 28SrDNA. Xylophaga brava sp. nov. appeared to be restricted to the Mediterranean and morphologically resembled the closely related X. cf. anselli from the Cantabrian Sea. However, they clearly diverged in two well-supported clades. Low levels of intraspecific variability and higher interspecific divergence between species also supported the existence of these two different species. Morphologically they differ in the number of cirri at the siphon openings, in the shape of the posterior shell and in the size of prodissoconch II. The new species is characterized by having weak, poorly mineralized mesoplax and siphons united throughout, covered by a periostracal, non-calcified tube; distinct proximal and distal siphons, the former translucent and soft, the latter muscular, with concentric rings. Xylophaga atlantica, previously known only from the western Atlantic, is reported for the first time in the Mediterranean Sea. Whether its presence in the Mediterranean indicates its natural distribution or reflects its recent introduction is unknown. Although xylophagaids have been previously reported to recruit heavily to wood deposited on the seabed, these four species colonized wood suspended 30 m above the seafloor. [ABSTRACT FROM AUTHOR]

Biogeography investigates spatial patterns of species distribution. Discontinuities in species distribution are identified as boundaries between biogeographic areas. Do these boundaries affect genetic connectivity? To address this question, a multifactorial hierarchical sampling design, across three of the major marine biogeographic boundaries in the central Mediterranean Sea (Ligurian-Tyrrhenian, Tyrrhenian-Ionian and Ionian-Adriatic) was carried out. Mitochondrial COI sequence polymorphism of seven species of Mediterranean benthic invertebrates was analysed. Two species showed significant genetic structure across the Tyrrhenian-Ionian boundary, as well as two other species across the Ionian Sea, a previously unknown phylogeographic barrier. The hypothesized barrier in the Ligurian-Tyrrhenian cannot be detected in the genetic structure of the investigated species. Connectivity patterns across species at distances up to 800 km apart confirmed that estimates of pelagic larval dispersal were poor predictors of the genetic structure. The detected genetic discontinuities seem more related to the effect of past historical events, though maintained by present day oceanographic processes. Multivariate statistical tools were used to test the consistency of the patterns across species, providing a conceptual framework for across-species barrier locations and strengths. Additional sequences retrieved from public databases supported our findings. Heterogeneity of phylogeographic patterns shown by the 7 investigated species is relevant to the understanding of the genetic diversity, and carry implications for conservation biology. [ABSTRACT FROM AUTHOR]

Groupers species are extremely vulnerable to overfishing and many species are threatened worldwide. In recent decades, Mediterranean groupers experienced dramatic population declines. Marine protected areas (MPAs) can protect populations inside their boundaries and provide individuals to adjacent fishing areas through the process of spillover and larval export. This study aims to evaluate the effectiveness of six marine reserves in the Western Mediterranean Sea to protect the populations of three species of grouper, Epinephelus marginatus, Epinephelus costae and Mycteroperca rubra, and to understand in which circumstances MPAs are able to export biomass to neighbouring areas. All the studied MPAs, except one where no grouper was observed, were able to maintain high abundance, biomass and mean weight of groupers. Size classes were more evenly distributed inside than outside MPAs. In two reserves, biomass gradients could be detected through the boundaries of the reserve as an indication of spillover. In some cases, habitat structure appeared to exert a great influence on grouper abundance, biomass and mean individual weight, influencing the gradient shape. Because groupers are generally sedentary animals with a small home range, we suggest that biomass gradients could only occur where groupers attain sufficient abundance inside MPA limits, indicating a strongly density-dependent process. [ABSTRACT FROM AUTHOR]

Background: Olive trees (Olea europaea subsp. europaea var. europaea) naturally grow in areas spanning the Mediterranean basin and towards the East, including the Middle East. In the Iranian plateau, the presence of olives has been documented since very ancient times, though the early history of the crop in this area is shrouded in uncertainty. Methods: The varieties presently cultivated in Iran and trees of an unknown cultivation status, surviving under extreme climate and soil conditions, were sampled from different provinces and compared with a set of Mediterranean cultivars. All samples were analyzed using SSR and chloroplast markers to establish the relationships between Iranian olives and Mediterranean varieties, to shed light on the origins of Iranian olives and to verify their contribution to the development of the current global olive variation. Results: Iranian cultivars and ecotypes, when analyzed using SSR markers, clustered separately from Mediterranean cultivars and showed a high number of private alleles, on the contrary, they shared the same single chlorotype with the most widespread varieties cultivated in the Mediterranean. Conclusion: We hypothesized that Iranian and Mediterranean olive trees may have had a common origin from a unique center in the Near East region, possibly including the western Iranian area. The present pattern of variation may have derived from different environmental conditions, distinct levels and selection criteria, and divergent breeding opportunities found by Mediterranean and Iranian olives.These unexpected findings emphasize the importance of studying the Iranian olive germplasm as a promising but endangered source of variation. [ABSTRACT FROM AUTHOR]

Marine protected areas (MPAs) were acknowledged globally as effective tools to mitigate the threats to oceans caused by fishing. Several studies assessed the effectiveness of individual MPAs in protecting fish assemblages, but regional assessments of multiple MPAs are scarce. Moreover, empirical evidence on the role of MPAs in contrasting the propagation of non-indigenous-species (NIS) and thermophilic species (ThS) is missing. We simultaneously investigated here the role of MPAs in reversing the effects of overfishing and in limiting the spread of NIS and ThS. The Mediterranean Sea was selected as study area as it is a region where 1) MPAs are numerous, 2) fishing has affected species and ecosystems, and 3) the arrival of NIS and the northward expansion of ThS took place. Fish surveys were done in well-enforced no-take MPAs (HP), partially-protected MPAs (IP) and fished areas (F) at 30 locations across the Mediterranean. Significantly higher fish biomass was found in HP compared to IP MPAs and F. Along a recovery trajectory from F to HP MPAs, IP were similar to F, showing that just well enforced MPAs triggers an effective recovery. Within HP MPAs, trophic structure of fish assemblages resembled a top-heavy biomass pyramid. Although the functional structure of fish assemblages was consistent among HP MPAs, species driving the recovery in HP MPAs differed among locations: this suggests that the recovery trajectories in HP MPAs are likely to be functionally similar (i.e., represented by predictable changes in trophic groups, especially fish predators), but the specific composition of the resulting assemblages may depend on local conditions. Our study did not show any effect of MPAs on NIS and ThS. These results may help provide more robust expectations, at proper regional scale, about the effects of new MPAs that may be established in the Mediterranean Sea and other ecoregions worldwide. [ABSTRACT FROM AUTHOR]

Through the study of the phylogeographic structure and demographic history of the common goby, Pomatoschistus microps, the influence of Quaternary climatic changes on the evolutionary history of coastal and marine fishes is investigated. Because of its sedentary life cycle in Mediterranean lagoons, it is also a good model to study more specifically if the formation of lagoons during the Holocene had an impact on population structure and demography. Mitochondrial sequences of Northeastern Atlantic and Western Mediterranean specimens were used for phylogenetic reconstructions as well as divergence time estimates, demographic history and population structure analyses. Pomatoschistus microps was a highly supported monophyletic clade including four lineages. It may have appeared 77,000 yr ago, and the divergence of its lineages likely occurred shortly thereafter (between 61,000 and 54,000 yr). Most lineages had polytomic topologies, low nucleotide diversity and demographic analyses providing evidence of population expansion. Each lineage was characterized by a large number of private haplotypes. Most haplotypes found in Mediterranean localities were endemic, and one was dominant. Complex reticulated relationships connecting North European, Atlantic and Mediterranean haplotypes were observed. Moderate to high population structure was underlined. Contrary to previous published studies, no significant differentiation was observed between Atlantic and Mediterranean populations, indicating that the Gibraltar Strait is not a phylogeographic break for P. microps. Indeed, molecular dating combined with the tree topologies, phylogeographic and demographic analyses as well as high haplotype diversity underline a recent and rapid population divergence during the last glacial. However, population structure indicates that differentiation is an ongoing process. From an ancestral population trapped in the Atlantic, this goby colonized first northern Europe and later the Mediterranean Sea. Shared haplotypes could have dispersed in the western Mediterranean basin before the lagoon formation, while most private haplotypes, evidencing a recent isolation, probably diverged in lagoons after their closure. [ABSTRACT FROM AUTHOR]

The Atlantic bonito (Sarda sarda, Bloch 1793) belongs to the important marine fish species with a wide geographical distribution covering the Atlantic Ocean, the Mediterranean and its bordering seas. Aquaculture practices for this species are still in their infancies and scientific studies are seldom undertaken, mainly because of difficulties in sampling. Thus for small tuna species like the Atlantic bonito only little is known about its biology and regarding the molecular background even less information is available. In the production of marine fish it is known that the most critical period is the larval stages, as high growth rates as well as significant developmental changes take place. In this study we have investigated the transcriptome of the Atlantic bonito of five larvae stages applying Illumina sequencing technology. For non-model species like aquaculture species, transcriptome analysis of RNA samples from individuals using Illumina sequencing technology is technically efficient and cost effective. In the present study a total number of 169,326,711 paired-end reads with a read length of 100 base pairs were generated resulting in a reference transcriptome of 68,220 contigs with an average length of 2054 base pairs. For differential expression analyses single end reads were obtained from different developmental stages and mapped to the constructed reference transcriptome. Differential expression analyses revealed in total 18,657 differentially expressed transcripts and were assigned to five distinguished groups. Each of the five clusters shows stage specific gene expression. We present for the first time in the Atlantic bonito an extensive RNA-Seq based characterization of its transcriptome as well as significant information on differential expression among five developmental larvae stages. The generated transcripts, including SNP and microsatellite information for candidate molecular markers and gene expression information will be a valuable resource for future genetic and molecular studies. [ABSTRACT FROM AUTHOR]

DNA- and RNA-based PCR and reverse-transcription real-time PCR assays were developed for diagnostic detection of the vcpA zinc-metalloprotease implicated in the virulence of the coral pathogen Vibrio coralliilyticus. Both PCR methods were highly specific for V. coralliilyticus and failed to amplify strains of closely-related Vibrio species. The assays correctly detected all globally occurring V. coralliilyticus isolates including a newly-described isolate [TAV24] infecting gorgonians in the Mediterranean Sea and highlighted those isolates that had been potentially misidentified, in particular V. tubiashii strains ATCC 19105 and RE22, historically described as important oyster pathogens. The real-time assay is sensitive, detecting 10 gene copies and the relationships between gene copy number and cycle threshold (CT) were highly linear (R2≥99.7). The real-time assay was also not affected by interference from non-target DNA. These assays are useful for rapid detection of V. coralliilyticus and monitoring of virulence levels in environmental samples, allowing for implementation of timely management steps to limit and possibly prevent losses due to V. coralliilyticus infection, as well as furthering investigations of factors affecting pathogenesis of this important marine pathogen. [ABSTRACT FROM AUTHOR]

Terrestrial inputs (natural and anthropogenic) from rivers, the atmosphere and physical processes strongly impact the functioning of coastal pelagic ecosystems. The objective of this study was to develop a tool for the examination of these impacts on the Marseille coastal area, which experiences inputs from the Rhone River and high rates of atmospheric deposition. Therefore, a new 3D coupled physical/biogeochemical model was developed. Two versions of the biogeochemical model were tested, one model considering only the carbon (C) and nitrogen (N) cycles and a second model that also considers the phosphorus (P) cycle. Realistic simulations were performed for a period of 5 years (2007–2011). The model accuracy assessment showed that both versions of the model were able of capturing the seasonal changes and spatial characteristics of the ecosystem. The model also reproduced upwelling events and the intrusion of Rhone River water into the Bay of Marseille well. Those processes appeared to greatly impact this coastal oligotrophic area because they induced strong increases in chlorophyll-a concentrations in the surface layer. The model with the C, N and P cycles better reproduced the chlorophyll-a concentrations at the surface than did the model without the P cycle, especially for the Rhone River water. Nevertheless, the chlorophyll-a concentrations at depth were better represented by the model without the P cycle. Therefore, the complexity of the biogeochemical model introduced errors into the model results, but it also improved model results during specific events. Finally, this study suggested that in coastal oligotrophic areas, improvements in the description and quantification of the hydrodynamics and the terrestrial inputs should be preferred over increasing the complexity of the biogeochemical model. [ABSTRACT FROM AUTHOR]