• Energy Research

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.

This dataset gathers total species richness, total abundance and total biomass of fishes recorded in six Mediterranean Marine Protected Areas in summer by underwater visual censuses performed on rocky areas at varying distances from the core of the MPA. Belt transects (25 x 5 m) were run parallel to the coast between 6 and 12 m depth, except in Tabarca Posidonia beds (50 x 5 m). Additionally, reduced fish species richness, abundance and biomass excluding zooplanktivorous fish species (Atherinidae, Clupeidae, Centracanthidae, Engraulidae, Pomacentridae, and the Sparidae Boops boops) were given as their fluctuating abundance and aggregative behavior may mask the effect of protection. Location of the 6 Mediterranean Marine Protected Areas

This dataset gathers the names of 86 species of fish as well as their trophic category, abundance and biomass per replicate, sampled by bottom trawling in Posidonia oceanica beds in three main geographic areas (Marseille, Port-Cros Island and Galeria in Corsica) of the Mediterranean French coast. Samples were collected by bottom trawling performed in seagrass meadows between 10 and 40 m depth at different seasons (summer-winter) and period (day-night) at several occasions between 1980 and 2013. This dataset is a witness of the structure, functioning and evolution of fish assemblages in north-western Mediterranean Posidonia oceanica beds.

Significance Species loss can weaken the trophic interactions that underpin ecosystem functioning. Coral reefs are the world’s most diverse marine ecosystem, harboring interaction networks of extraordinary complexity. We show that, despite this complexity, global coral reef food webs are governed by a suite of highly consistent energetic pathways, regardless of regional differences in biodiversity. All networks are characterized by species with narrow dietary preferences, arranged into distinct groups of predator–prey interactions. These characteristics suggest that coral reef food webs are robust to the loss of prey resources but vulnerable to local extinctions of consumer species.

This dataset gathers, total abundance, abundance per size class, total biomass and biomass per size class of two vulnerable fish species, the dusky grouper, Epinephelus marginatus (Lowe, 1834), and the brown meagre, Sciaena umbra Linaeus, 1758, recorded inside and outside the Marine Natural Reserve of Scandola (Corsica, NW Mediterranean) in 2012 and 2018. Fish were recorded by underwater visual censuses performed on belt transects (50 x 15 m) run parallel to the coast between 1 and 40 m depth at 13 sites according to three levels of protection status (integral reserve, buffer zone and unprotected zone). A total of 532 transects were performed in 2012 and 526 in 2018. Corsica 2012-2018-Map Scandola Marine natural Reserve

This dataset gathers data used to infer the trophic structure and functioning of fish assemblages in the Eastern English Channel, the Bay of Biscay and the Gulf of Lions : - Biomass data, resulting from accoustic monitoring for pelagic species, or bottom trawling for demersal species, after extrapolation based on stratification scheme - Individual C and N isotopic ratios, length and mass, for all individuals considered - Individual energetic density values

PCB levels in plankton were investigated in the Bay of Marseille, Western Mediterranean Sea, between September 2010 and October 2011. Concentrations of PCB congeners (CB 18, CB 52, CB 101, CB 118, CB 138, CB 153, CB 180) were determined in three plankton size-classes (60-200, 200-500 and 500-1000μm) together with different parameters: chlorophyll content, plankton dry-weight biomass, carbon and nitrogen stable isotope ratios and plankton-community structure. The ∑PCB7 concentrations ranged between 14.2 and 88.1ngg(-1)d.w., for all size classes and all sampling periods. The results do not show the biomass dilution effect and indicate moderate but significant biomagnification with plankton trophic position estimated by δ(15)N signatures. Equilibrium with water phase may notably contribute in controlling the PCB levels in the plankton. More generally, presented results imply that PCB accumulation in the plankton is an effect of abiotic and trophic complex interactions in the Bay of Marseille.