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The structure of a fish food-web was described for the first time in a coastal lagoon in the southern Mediterranean Sea by analysing stable carbon and nitrogen isotopes of fish species and their potential food sources. The El Mellah Lagoon (EML) located in extreme north-eastern Algeria, is the only coastal lagoon in the southern Mediterranean with low human pressure due to few human activities and its protected status under the Ramsar Convention. We investigated the structure of the fish food-web in the spring at four stations in the lagoon that differed in their proximity to rivers and the channel, which connects to the sea. The results provided insight into ecological functions of EML as a feeding area for all fish species caught in the lagoon, in particular marine migrant juveniles and resident species. The δ13C results highlighted the importance of marine organic matter on the functioning of the EML fish food-web, to which organic matter in marine sediments and likely microphytobenthos contribute most. Our study also revealed the importance of seagrass (Ruppia sp.) for detritivorous fish (i.e., Mugilidae species) and for their potential to shelter a wide variety of benthic invertebrates that are potential food sources for benthivorous fish. Our study revealed the small influence of freshwater inputs on the functioning of the EML food-web and that juvenile marine fish may use the lagoon for reasons other than feeding, most likely to avoid predation and obtain physiological advantages.

International audience; The seasonal pattern of microplastics (MPs) contamination of the French littoral area of the Pertuis Charentais, one of the main French shellfish production regions, was assessed for the first time, between May 2019 and May 2020 at four different sites. The reference site was located at “Ile de Ré” and the other sites were located in the estuaries of the Sèvre Niortaise, Charente and Seudre rivers. Both blue mussels (Mytilus edulis) and Pacific oysters (Magallana gigas), that are considered sentinel species for the quality of the marine environment were analysed, along with sediment and seawater samples. MPs were extracted from each sample, counted, measured and sorted by colour and type. Micro-Raman spectroscopy was used to determine the proportion of confirmed MPs and the polymer types. The results showed that the contamination of mussels by fibres and fragments (1.9 ± 2.1 MPs/g ww) was significantly higher than for oysters (0.4 ± 0.4 MPs/g ww). Specifically, the contamination by fibres in both species was significantly greater than the contamination by fragments. Significant variations of MPs contamination were observed across the seasons and sites in bivalves, and depended on the species and the type of MPs (fibres or fragments). Mean concentrations of MPs measured in water and sediment were 0.007 MPs/L and 210 MPs/kg dw, respectively. Finally, blue was the dominant colour for fibres (79%) and fragments (81%). Blue fragments were mainly made of PS (70%) followed by PC (18%) and PP, PA or PLA (3%) whereas blue fibres were mainly made of PA (80%) followed by PET (13%) or PP (7%). This rare environmental case study of long-term chronic exposure of farming areas to MPs provides new knowledge on in situ variations of plastic fibres and fragments contamination throughout the seasons.

International audience; The main objective of this study was to improve our knowledge on the responses of fish populations to multistress (diffuse pollution and warming waters) in estuaries. Adult flounders were caught in two estuaries in the Eastern English Channel: the heavily polluted Seine estuary vs the moderately contaminated Canche estuary. Fish samplings were conducted in January just before the reproduction period, and in July when gonads were at rest. The overall rise in coastal winter water temperatures detected over the Channel impairs the flounder's phenology of reproduction in the two estuaries, inducing a delay of maturation process and probably also spawning. The higher liver histopathology index in Seine vs Canche could be the consequence of the fish exposition to a complex cocktail of contaminants in a strongly industrialized estuary. Higher levels of neurotoxicity, gill lipid peroxidation, and liver EROD activity were observed in Seine vs Canche. Furthermore, a possible impairment in mitochondrial metabolism was suggested in the Seine flounder population. We confirmed in this study the potential role of two membrane lipids (sphingomyelin and phosphatidylserine) in the resistance towards oxidative stress in Seine and Canche. Finally, we suggest that the Seine flounder population (and possibly the connected Eastern English Channel flounder populations over the French Coast) could be seriously impacted in the future by multistress: higher winter temperatures and chemical contamination.

International audience; This study investigates the effect of fish density and exposure duration on trace metal elements (TME) bioaccumulation and several biomarkers response. Juvenile flounders were caged at low, medium and high densities and exposed during 15 or 30 days in the Seine estuary. The concentrations of the TME measured in the muscle of the caged fish were all in agreement with their bioavailability percentage in the sediments. Higher concentrations of TME were found in flounders' muscle exposed for 15 days compared with those caged for 30 days. For the same exposure time, the density of fish had no effect on the accumulation of the TME in the flounders' muscle. Biomarkers responses varied according to density and duration of exposure. Special care should be taken in their interpretation. We underline that for an optimal assessment of TME pollution in the field, 15 days with low densities of fish per cage are sufficient.

International audience; The aim of this paper is to examine fishermen's Local Ecological Knowledge (LEK) relating to Marine Protected Area (MPA) planning and the overlap with fisheries management in the future “Taza” MPA (Algeria, SW Mediterranean). The case study focuses on both commercial and recreational coastal fisheries from the fishing harbour of Ziama (NE Algeria). In this area, coastal fishing is carried out by professional small-scale fishers and purse seiners for commercial fishery and by recreational boat fishers for recreational fishery. While there have been some science-based studies in the characterization of this coastal fishery by using direct observation of landings as a method for estimating catch and fishing effort, fishermen's LEK remains under-utilized in this Social-Ecological System (SES). To address this knowledge gap, perceptions regarding: (1) biological and ecological impacts of coastal fisheries, (2) marine ecosystem health and (3) attitudes towards the proposed MPA regulations were analyzed in order to assess potential social-ecological impacts which can inform more accurately on MPA planning and fisheries management in the future. To this end, thirty face-to-face semi-structured interviews with fishers at Ziama harbour were carried out between June and September 2017. The study found that the future establishment of the “Taza” MPA may affect the fisheries in this area in the short-term, and in particular the jobs and livelihoods of professional fishers by limiting the fishing area through new fishing restrictions. The fishermen's LEK provided some capacity to understand the heterogeneity of the SES in place and may be used as a tool to evaluate the outcome of fishery management actions. The results indicate higher acceptance rates among recreational than professional fishers regarding no-take zones. Professional fishers were proportionately more likely to oppose the new regulations, though 53% of the fishers surveyed were uncertain about the future positive impacts of the MPA. The LEK provides managers with a level of detail about the prediction and prevention of fishermen opposition, and can point out opportunities for improving conservation policy with respect to social acceptance.

The objective of this study was to develop an integrative approach in ecotoxicology (from biomarkers to population genetics) to assess the ecological status of fish populations. Flounders (Platichthys flesus) collected after the spawning season in the heavily polluted Seine estuary were compared with the moderately polluted Bay of Douarnenez. The muscle energetic reserves were highly depleted in Seine vs. Douarnenez fish. The Seine fish displaying a reduced capacity to manage the oxidative stress and a higher energetic metabolism. An increase in the content of muscle membrane phospholipids (sphingomyelin, phosphatidylserine, free sterols) was detected in the Seine vs. Douarnenez fish. The data integration allowed to hypothesize relationships between membrane phospholipids, xenobiotic metabolism, bioenergetics, and antioxidant defence. The genetic diversity considering neutral markers was maintained in the heavily polluted Seine population compared with the Douarnenez population. Finally, we suggest that the high physiological cost of tolerance to toxicants in the Seine flounder population could compromise its capacity to respond in the future to an additional stressor like warming waters in shallow depth. Thus, this population could be submitted to an ecological risk.

A total of 1229 specimens representing 11 commercial fish species caught off the coast of Algeria were examined for parasitic nematodes (larvae) from November 2015 to April 2017. Four nematode species belonging to Anisakis (1 species) and Hysterothylacium (3 species) genera were identified. The presence of A. simplex parasitism in Trachurus trachurus was significantly related to the length (p < 0.05) of the fish and the season of its capture (p < 0.05), but not to its sex (p = 0.61%). Large benthic species and some pelagic species show high rates of infection with parasitic nematodes and therefore pose considerable health risk (anisakiasis) thereby compromising food safety. An up-to-date reference checklist of nematode species collected from the North African fish species was compiled with specific relationships between parasitic nematodes and their hosts and/or their collecting location indicated.

A simple, rapid and robust method for routine speciation analysis of methylmercury (MeHg) by reversed phase high-performance liquid chromatography coupled to inductively coupled plasma-mass spectro...

Despite emerging and increasing concerns related to marine micro and macroplastics, no systematic surveys have been undertaken yet in the Lebanese marine area. To understand the spatio-temporal variation of plastic litter (macro and microplastics) in the Lebanese marine environment and to determine the sources of pollution, this study investigated the characteristics of plastic pollution in sea surface waters during wet and dry seasons in 22 sites of Beirut and Tyre regions. A total of 23,023 items were identified and assessed according to the shape, color, and concentration; moreover, the risk of microplastics (MPs) contamination was explored based on a risk assessment model. The obtained results demonstrated that the average macroplastics concentration was 0.45 ± 0.6 items/m3. The average microplastics concentration was found to be 20.1 ± 21.8 and 3.78 ± 5.2 items/m3 in spring and fall respectively. During fall, MPs fragments were dominant in Beirut (97%) and Tyre (91%), and no pellets were observed. During spring, filaments were most encountered in Beirut (76.5%). The most dominant marine litter color was blue followed by black and white. The Pollution Load Index (PLI) values showed a moderate contamination of the Lebanese coast with MPs (PLI: 5.79 ± 3.93) except for several sites in Beirut that showed high values of PLI, highlighting the local influence of cities and rivers on MPs concentration. This study serves as an important baseline for understanding the characteristics of the seasonal variation of MPs along the Lebanese marine environment; it will help stakeholders and countries to take proactive and reactive actions to face plastic litter pollution in the Lebanese coastal area.

International audience; This study investigated the role of a municipal wastewater treatment plant (WWTP) effluent and an abandoned coastal landfill as pathways for microplastics (MPs) input into the marine environment. MPs were first analyzed in raw sewage influent, sludge and effluent samples, and their fate was studied along a distance gradient from the WWTP in three matrices: surface water, sediments and wild mussels. All suspected MPs were characterized according to their polymer nature using micro-Raman spectroscopy. The investigated WWTP had an estimated daily discharge of 227 million MPs. MPs were found in all matrices with a decreasing abundance from the effluent. Strong MPs abundances (higher than those found near the WWTP effluent) were observed in the vicinity of the coastal landfill suggesting its importance as a MPs entry route into the marine coastal environment. Our study supports the idea that blue mussels are a promising sentinel species for MPs (

International audience; Nowadays, recreational fisheries (REC) have a great impact on marine ecosystems and create conflicts with other human coastal activities such as commercial small-scale fisheries (SSF). In the proposed “Taza” marine protected area (MPA) (Algeria, SW Mediterranean), recreational boat fishing is poorly regulated and its catches remain unmonitored. In addition, a significant number of REC fishers sell their catch illegally, an activity we could refer to as IUU (Illegal, Unreported, and Unregulated) fishing. This study is a good opportunity to evaluate the potential conflicts between recreational IUU and commercial fisheries and can be extremely valuable in terms of MPA planning and fisheries monitoring by providing baseline data for setting up sound fisheries management and conservation plans. Two fishing harbors are located near the proposed “Taza” MPA: Boudis and Ziama. Illegal REC boats from Ziama harbor were studied via a direct observation method of landings developed by the Ifremer (French Research Institute for Exploitation of the Sea). A comparison between illegal REC and SSF boats was highlighted in terms of catches and fishing effort. A total of 54 taxa belonging to 24 families were observed in the catches of the 32 recreational active boats in this harbor between May 2013 and April 2014. The proportion of the harvest attributed to illegal REC represented about 50% of the SSF harvest. Illegal REC in the proposed “Taza” MPA is an important socioeconomic activity which is intensively practiced throughout the year. From November to April, the mean catch was almost the same for both fishing categories. Strong competition between recreational and professional fishers for the natural resources was highlighted as 81% of the 54 caught taxa were present in the catches of both fishing categories (i.e. 44 taxa). Moreover, 4 species of high commercial value were caught exclusively by recreational fishers. Finally, the managers of the proposed “Taza” MPA must address and regulate all fishing activities and use the best available information in order to provide important benefits to marine ecosystems, fishers, and the local population.

International audience; The effectiveness of mussel caging for active microplastics (MPs) biomonitoring was investigated for the first time by comparing abundance and characteristics (shape, size, color and type of polymers) of MPs ingested by caged depurated blue mussels with those ingested by native mussels collected at the same sites and with those found in their surrounding environment (surface water and sediments). Mussels were exposed along a pollution gradient originating from a wastewater treatment plant discharge and near an abandoned coastal landfill. After 6 weeks of deployment, the majority (93%) of clean transplanted mussels had ingested MPs with a mean number of items ranging from 0.61 to 1.67 items/g. The occurrence, abundance and properties of MPs ingested by caged mussels were similar to those found in native mussels. Among the debris items detected in caged and native mussels, fragments were the most predominant type, consistent with the MPs found in their surrounding environment. MPs sizes were very similar whether in the water, sediments and both caged and native mussels, with a dominance of items

International audience; Estuaries are important areas highly vulnerable to anthropogenic pollutions. Therefore, the assessment of estuarine water quality is a major ecological issue. In this study, we sampled juveniles of the European flounder in the “pristine” Canche estuary, and caged them in Canche and in two polluted sites of the Seine estuary, Rouen and Fosse Nord. After one month, the metal and organic pollutants in these sites were assessed, and we evaluated several phenotypic indicators (condition index, RNA/DNA ratios and genotoxicity), and extracted the proteins in fish livers for analysis using a shotgun proteomics approach.The results showed strong modifications in the fish caged in both sites of the Seine estuary, as compared to those caged in Canche. In particular, many proteins involved in phase I and phase II detoxification reactions were accumulated in the liver of fish caged in the site showing the highest pollution, Rouen. In addition, we observed a general disruption of metabolism, in particular an increase in lipid synthesis and carbohydrate degradation in Rouen, and a decrease in the abundance of proteins associated to translational activity in Fosse Nord. At both sites, several stress proteins were decreased.The proteomic impact of the encagement by itself was also evaluated, by comparing the liver proteome of fish caged in Canche to that of fish stayed in natura during the same time. The results showed proteomic signatures of exposure to stressful conditions (particularly heat stress), most probably related to the micro-habitat in which the cages were placed. In conclusion, the caging technique is of great interest for ecotoxicological assessment of estuarine waters, but should consider that the results are representative of the micro-habitat around the cages, which does not necessarily represent the overall heterogeneity of the estuarine environment.

International audience; Plastics are found to be major debris composing marine litter; microplastics (MP, < 5 mm) are found in all marine compartments. The amount of MPs tends to increase with decreasing size leading to a potential misidentification when only visual identification is performed. These last years, pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) has been used to get information on the composition of polymers with some applications on MP identification. The purpose of this work was to optimize and then validate a Py-GC/MS method, determine limit of detection (LOD) for eight common polymers, and apply this method on environmental MP. Optimization on multiple GC parameters was carried out using polyethylene (PE) and polystyrene (PS) microspheres. The optimized Py-GC/MS method require a pyrolysis temperature of 700 °C, a split ratio of 5 and 300 °C as injector temperature. Performance assessment was accomplished by performing repeatability and intermediate precision tests and calculating limit of detection (LOD) for common polymers. LODs were all below 1 μg. For performance assessment, identification remains accurate despite a decrease in signal over time. A comparison between identifications performed with Raman micro spectroscopy and with Py-GC/MS was assessed. Finally, the optimized method was applied to environmental samples, including plastics isolated from sea water surface, beach sediments, and organisms collected in the marine environment. The present method is complementary to μ-Raman spectroscopy as Py-GC/MS identified pigment containing particles as plastic. Moreover, some fibers and all particles from sediment and sea surface were identified as plastic.

The Algerian coast receives significant inputs of metallic pollutants. To assess the accumulation of potentially toxic elements (Pb, Cd, Hg) by benthic fish and the consequent health risks for consumers, red mullet specimens (Mullus barbatus barbatus, Linnaeus, 1758) were sampled (n=424) in 3 sites along the Algerian coast (Algiers, Bejaia and Dellys) and analysed for Pb, Cd and Hg in muscles and liver. Spatio-temporal and biological variations were highlighted. The highest concentrations were observed in the liver for the three elements. Mean Pb and Cd concentrations are higher in Algiers specimens. However, the specimens from Dellys are more contaminated by Hg in the liver (0.35 ± 0 . 0001 μ g/g). Medium and large specimens show higher concentrations of the three metals. There was no clear seasonal pattern in concentration of Pb, while Hg concentrations are higher in autumn, and Cd in summer, spring and winter. No impact of the three metal elements on Fulton’s K and the hepato-somatic indexes was observed. Despite the average concentrations of Pb and Cd exceeded the recommended regulatory values, few risk related to the consumption of contaminated M. barbatus barbatus inhabiting the Algerian coasts were demonstrated.

Levels of 20 trace elements (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Sb, Ba, Hg, Pb, and U) were assessed in livers and muscles of two demersal fish species (Siganus rivulatus and Lithognathus mormyrus) and one pelagic species (Etrumeus teres) from the Lebanese coast located in the Eastern Mediterranean. The samples were collected from three sites along the Lebanese coast during the wet and dry seasons in 2017. The trace elements were more concentrated in livers than in muscles and interspecific differences were also found. The herbivorous species S. rivulatus showed the highest levels for most trace elements, while the carnivorous species L. mormyrus showed the least contamination. Elemental seasonal differences were species dependent and were observed for Ti, Cr, Mn, Fe, Ni, As, and Hg, with higher values during the wet season. Multivariate analysis showed spatial differences mainly during the wet season, while being closely related to species that reflected different accumulation patterns in each site. Levels of most trace metals in livers were higher than those reported in other Mediterranean regions (up to 2 to 3 folds). Nevertheless, the levels of Cd, Pb, and Hg in fish muscle were below the maximum levels set by the European Commission indicating that the consumption of these fish species is not likely to have adverse effect on human health. However, exposure depends on dietary habits of the population and a continuous exposure to these elements may result in adverse effects.

International audience; The establishment of marine protected areas (MPAs) in Algeria faces several obstacles, particularly lack of legislation and poor management of local resources. The attempt to establish an MPA at Taza (Gulf of Béjaia, SW Mediterranean) is part of a broader project to set up a network of MPAs in the Mediterranean basin. The MPA of Taza was first proposed by the staff of Taza National Park in 2000, who, with the support of the MedPAN (Network of Managers of Marine Protected Areas in the Mediterranean) South Project (MSP), began promoting this initiative in 2009. This study analyzes the purse seine fishery in this coastal area through the study of landings and yields, in order to characterize one of the most important fishing activities in the Gulf of Béjaia. In addition, the study assesses the impact of non-purse seine vessels which has detrimental effects leading to a de facto open access fishery situation. Landings observation and interviews with purse seine fishers (i.e. vessels with a license to practice purse seining) were conducted from May 2013 to April 2014 to record catches, the characteristics of fishing gear, and the fishing grounds. At the same time, non-purse seine fishing vessels - that is, vessels without a license to practice purse seining - were also monitored. The purse seine fishery of Ziama shows a seasonal pattern in the selection of fishing grounds. The species most frequently landed by purse seine and non-purse seine vessels throughout the study period was the sardine (Sardina pilchardus). Other less frequently caught species such as the European anchovy (Engraulis encrasicolus) make a seasonal appearance. This data could be useful to understand fishery dynamics and the behavior of fishers prior to the establishment of an MPA in a given zone.

Otolith shape analysis is an efficient fish stock identification tool. However, most applications used left and right otoliths or only one of them arbitrarily chosen without testing for biases resulting from potential directional bilateral asymmetry (DA) in otolith shape, i.e. a unimodal population-level deviation form bilateral symmetry between right and left otolith shapes. In this study, 560 bogues (Boops boops) were sampled from 11 geographical locations from the Canary Islands to the Aegean Sea and elliptical Fourier descriptors were used to describe their otoliths’ shape. First, a significant otolith DA was observed at the global scale with an average amplitude of 2.77%. However, at the scale of sampling locations, DA was not always significant and varied in amplitude and direction. Second, population structure was investigated using the shape of either right otoliths or left otoliths or both together. Analyses based on right otoliths or both otoliths together, suggested three stock units: a North-Western Mediterranean Sea stock, an Eastern Mediterranean Sea stock, and a Central-Eastern Atlantic Ocean and SouthWestern Mediterranean Sea stock. In contrast, no coherent geographical pattern was found based on left otoliths. Our results highlight the importance of accounting for potential otolith DA in otolith shape-based stock identification., Sí

This summary of the Senegalese coastal and marine environment is based on both reviews of recent scientific knowledge and new data by the authors. The coastal and marine habitats, environmental conditions, and its biodiversity are described. Climate change and the major threats to biodiversity and habitats are then discussed. Senegal’s coasts are affected by a number of environmental problems, including pollution, coastal erosion, coastal flooding, soil and water salinization, mangrove degradation, and a reduction in fish stocks. Fisheries play an important socioeconomic role for Senegal and a focus on fisheries resources is presented. Finally, management regimes for coastal ecosystems, biodiversity, and fishery conservation are presented.

Jemaa Sharif, Perrine Cuvilliers, Mahmoud Bacha, Gaby Khalaf et Rachid Amara. A study on the diet variation of European anchovy (Engraulis encrasicolus) in the Atlantique and Mediterranean water. 2016. Lebanese Science Journal, 17(1): 77-92. This study evaluated diet variation of European anchovy Engraulis encrasicolus in productive and oligotrophic areas. The diet of the European anchovy was studied at 13 different sites along its geographic distribution range. In all sites, the diet was mainly based on copepods that represented 33 to 98% of the prey identified and were found in over 80% of the stomachs analyzed. The dominant copepod species and the various secondary preys such as ostracods, gastropods, and eggs varied among locations. Multivariate analyses (AFC, CAH, nMDS) distinguished three groups according to sites: group 1 in the Northwestern Mediterranean, Atlantic, Channel/North Sea; group 2 in the Algero-Provençal Basin (Ghazaouet, Bénisaf and Bejaia); and group 3 in the Eastern Mediterranean (Lebanon and Turkey). The differences among groups were based on the presence of specific prey types, such as, zooplankton, cyprid larvae, barnacles in the first group, bivalves and amphipods in the second group, and ostracods, mysids, and euphausiids in the third group. These groupings reflected the dissimilarities of hydrographic characteristics and biological productivity between regions. Examination of the stomach contents highlights the significant presence of plastic (13-16% of the content in some sites), where the vast majority came from fishing gear filaments.

Concentrations of 11 elements were quantified in five marine species from different trophic levels of a food web (algae, mussel, shrimp and fish), representative for shallow Senegalese coastal waters, and including species of commercial importance. Significant differences in element concentrations and bioaccumulation were demonstrated, revealing the utility of employing a suite of organisms as bioindicators to monitor metal contamination in coastal areas. There was no clear seasonal pattern in concentration of elements, however inter-site differences were observed. Calculations of transfer factors for all the studied elements showed that transfer factors from water were greater than those from sediments. For shrimp and mussel, the concentrations of Pb and Cd were below the EU's maximum level for human consumption, however high concentrations of arsenic in shrimp were recorded at all sites.

International audience; Microplastics (MPs), plastics with particles smaller than 5 mm, have been found almost in every corner of the world, especially in the ocean. Due to the small size, MPs can be ingested by animals and enter the marine trophic chain. MPs can affect animal health by physically causing damage to the digestive tract, leaking plastic chemical components, and carrying environmental pollutants and pathogens into animals. In this study, impacts of MPs ingestion on gut microbiota were investigated. Filter feeding mussels were exposed to “virgin” and “weathered” MPs at relatively realistic concentration 0.2 mg L−1 (“low”) and exaggerated concentration 20 mg L−1 (“high”) for 6 weeks. Influence in mussel gut microbiota was investigated with 16S rRNA gene high-throughput sequencing. As compared with non-exposed mussels, alteration of gut microbiota was observed after mussels were exposed to MPs for 1 week, 3 weeks, 6 weeks, and even after 8-day post-exposure depuration. Potential human pathogens were found among operational taxonomic units (OTUs) with increased abundance induced by MP-exposure. Faecal pellets containing microorganisms from altered gut microbiota and MPs might further influence microbiota of surrounding environment. Our results have demonstrated impacts of MP-exposure on mussel gut microbiota and suggested possible consequent effects on food quality, food safety, and the well-being of marine food web in the ecosystem for future studies.

In this study, levels of 20 trace elements (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Sb, Ba, Hg, Pb and U) and the respective biota–sediment accumulation factors (BSAF) were assessed for three marine species from the Eastern Mediterranean (Lebanese coast) belonging to different trophic levels in the food chain (algae, bivalves and shrimps). Multivariate analyses showed significant differences in trace element accumulation between seasons, sites and species thus highlighting the importance of a multi-species and seasonal approach to monitor trace metals in coastal areas. Biota–sediment accumulation factors (BSAF) showed limited transfer from sediments to marine organisms suggesting that the bioaccumulation of trace elements by marine organisms should be assessed by considering multiple sources of contaminants. Lead (Pb) levels (0.07–4.44​ mg.kg−1) measured in algae and Cd (0.54–7.74 mg.kg−1) and Zn (42.88–972​ mg.kg−1) levels found in the oyster, were similar and sometimes higher than those found in other polluted areas indicating that the Lebanese coast is subject to environmental pollution.

Eutrophication as a consequence of anthropogenic nutrient enrichment is one of the major threats to biodiversity in nearshore and coastal marine waters, and consequently, for ecosystem functioning. This study explores changes in the biological organization of copepod assemblages along a Chl a gradient through an upscaling analysis of regional datasets from the coastal waters of the Mediterranean Sea. Results show that omnivorous copepods using passive and/or ambush feeding strategy are favored as Chl a increases, and copepod community shifts towards trophic homogenization by favoring generalist feeders against specialists. To our knowledge, this is the first report of functional homogenization of copepods as the result of eutrophication. The present study also demonstrates the potential use of trait-based approaches to explore the effect of human disturbances on marine copepod assemblages in marine ecosystems.

International audience; The Mediterranean Sea is the largest semi-enclosed sea and one of the worst affected regional seas with sub-basin scale heterogeneity in plastics concentration. Few studies on microplastics (MPs) pollution have been conducted in the Eastern part of the Mediterranean basin. This study aims to evaluate, for the first time, the MPs pollution of the Lebanese coast (Levantine Basin) as well as the most common polymers found, and to assess the potential role of coastal landfills in this pollution. Two important seafood species that are wholly consumed by the Lebanese community: the European anchovy, Engraulis encrasicolus, and the spiny oysters, Spondylus spinosus, were sampled in three different sites englobing the littoral (Tripoli, Beirut and Sidon). Sea water and sediment samples were also collected from the same sites. Results showed different patterns of MPs concentration in the analyzed matrices: Sidon water sample was highly contaminated in MPs (6.7 MPs/m3) while Tripoli had the highest MPs in sediments (4.68 MPs/g). The occurrence of MPs in the biota was high (83.4% and 86.3% in anchovies and spiny oysters, respectively). Both anchovies and oysters from Beirut region had the highest ingested MPs/individual (2.9 ± 1.9 and 8.3 ± 4.4 MPs/individual, respectively). This study is the first that investigated microplastics ingestion by Spondylus spinosus while indicating the most common polymers found in the three matrices (water, sediments and biota) in the Eastern Mediterranean. These results highlighted the high MPs pollution found in the Levantine Basin in comparison to other Western Mediterranean regions. In addition, the obtained results indicate a potential contribution of coastal landfills to this pollution.

International audience; Estuaries serve as nursery grounds for many marine fish species. However, increasing human activities within estuaries and surrounding areas lead to significant habitat quality degradation for the juveniles. In recent years, plastic pollution has become a global environmental issue as plastic debris are found in all aquatic environments with potential adverse impacts on marine biota. Given the important ecological role of estuaries and implications of microplastics (MP) in ecosystems, here we assess the occurrence, number, size and polymer types of MP ingested by wild and caged juveniles European flounder (Platichthys flesus). We deployed caged fish for one month at five sites in three estuaries in the Eastern English Channel. The Seine estuary, heavily impacted by manmade modifications and one of the most contaminated estuaries in Europe, was compared to two smaller estuaries (Canche and Liane) less impacted by industrial activities. We found that juvenile flounders (7- 9 cm) were vulnerable to plastic ingestion. 75% of caged fish and 58% of wild caught fish had the presence of MP items in their digestive tract. Fibers (69%) dominated in the fish’s digestive tract at all sites. An average of 2.04 ± 1.93 MP items were ingested by feral juveniles flounder and 1.67 ± 1.43 by caged juveniles flounder. For the caged fish, the three sites impacted by wastewater treatment plant (Liane, Le Havre Harbor and Rouen) were those with the highest percentage of individuals that have ingested MP items. Most of the isolated items were fibers and blue in color. Polymers identified by micro Raman spectroscopy were Polycaprolactam, Polyethylene Terephtalate and Polyurethane. Although other environmental factors may have affected caged fish condition and mortality, we found no significant correlation with the number of ingested MP. However, the high occurrence of MP ingested by juvenile fish on nursery grounds raises concerns on their potential negative effects for fish recruitment success and population renewal. Finally, this study describes, for the first time, the feasibility of using caged juvenile fish as an assessing tool of MP contamination in estuarine nursery grounds.

International audience; Artisanal Small-Scale Fisheries (SSFs) are a primordial and very diverse activity in the Mediterranean, also within Marine Protected Areas (MPAs). This diversity is explained in terms of target species, gears, and fishing strategies. The main objective of this work was to investigate the spatio-temporal dynamics of artisanal SSFs of the future MPA of “Taza” (Algeria, SW Mediterranean). Data were collected through direct assessment of daily landings and using questionnaires. They were the subject of multivariate analyses that allowed us to identify the métiers practiced by artisanal fishers. During the one year (May 2013 to April 2014) field work period, 1330 fishing trips and 1613 fishing operations in 16 fishing grounds were recorded in the Ziama fishing harbor, where 15.2 tons of total catch was assessed. Our results show that, in the study area, the boats are predominantly gillnetters and that among the five métiers characterized by target species, gear type, fishing grounds, and fishing seasons, two métiers (“Mullus surmuletus trammel net” and “Sparids monofilament gillnet”) are practiced throughout the year, while the remaining three (“Sarda sarda driftnet”, “Merluccius merluccius set gillnet”, and “Pagellus set gillnet”) are specific to a determined period of the year. The ‘Mullus surmuletus trammel net’ métier represents 40% of the total fishing operations, of which 57.5% are carried out in the coastal sector at - 25 m. This study could contribute to defining the appropriate management approaches for SSFs in the future MPA of “Taza” by providing baseline information to build a sound management plan. In Algeria, it will certainly serve as a scientific reference in terms of zoning, protection of biodiversity, and specific monitoring at particular locations and periods of the year for the sustainable management of MPAs.