Alien marine species of Libya: first inventory and new records in El-Kouf National Park (Cyrenaica) and the neighbouring areas

The presence of marine alien species in El-Kouf National Park and the neighbouring areas was assessed using a compilation of available information and observations, a field survey conducted on October 2010 in the framework of the MedMPAnet project and results of further monitoring during June and September 2012. A total of 9 alien species were reported: the Rhodophyta Asparagopsis taxiformis (Delile) Trevisan de Saint-Léon, the Chlorophyta Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman & Boudouresque, the crab Percnon gibbesi (H. Milne-Edwards, 1853) and the fishes Fistularia commersonii Rüppell, 1838, Siganus luridus (Rüppell, 1829), Siganus rivulatus Forsskål, 1775, Pempheris vanicolensis Cuvier, 1831, Lagocephalus sceleratus (Gmelin, 1789) and Sphyraena flavicauda Rüppell, 1838. Several of them were until now unknown for the National Park. The list of alien marine species of Libya is updated and discussed. Until now 63 marine aliens species were recorded along the Libyan coasts. These include 3 Foraminifera, 3 Ochrophyta, 5 Rhodophyta, 5 Chlorophyta, 1 Magnoliophyta, 11 Arthropoda, 13 Mollusca, 1 Echinodermata and 21 Chordata. Among these Non Indigenous Species, 43 are known as established along the Libyan coast including 8 invasive, 11 casual, 6 questionable, 3 cryptogenic and 1 unknown. An in-depth study of the marine organisms would substantially increase the number of alien species occurring in Libya. Monitoring of marine assemblages of MPAs is a valuable opportunity to go further into the knowledge of native and introduced species

A combined approach to assessing the conservation status of Cap des Trois Fourches as a potential MPA: is there a shortage of MPAs in the Southern Mediterranean?

The Mediterranean basin is recognized as one of the most diverse regions on the planet, but is being threatened by overexploitation and habitat loss. Furthermore, the Strait of Gibraltar and adjacent Alboran Sea have been identified as representing an important habitat for many threatened or endangered species. In this context, one vehicle for marine conservation is the creation of marine protected sites, although Mediterranean Marine Protected Areas (MPAs) are neither large nor representative enough to form an effective network of protection. An inventory of the benthic communities and habitats of conservation interest has been carried out in Cap des Trois Fourches, an ecological and biogeographical site of interest. Univariate and multivariate analyses showed differences for marine communities among habitats and localities, indicating a great diversity in marine assemblages but an absence of a spatial gradient in marine α-diversity. The Trois Fourches area showed a high environmental quality and hosted several endangered species. Habitats of conservation concern, such as marine caves, seagrass meadows and coralligenous assemblages, were detected and studied. The scientific data recorded provide sound support for the establishment of a new MPA in Trois Fourches, taking into account that the findings match the scientific criteria required for declaration as a protected area. The benefits for connectivity at the Mediterranean scale and the local economy are discussed

Assessing the Health of Richibucto Estuary with the Latent Health Factor Index

The ability to quantitatively assess the health of an ecosystem is often of great interest to those tasked with monitoring and conserving ecosystems. For decades, research in this area has relied upon multimetric indices of various forms. Although indices may be numbers, many are constructed based on procedures that are highly qualitative in nature, thus limiting the quantitative rigour of the practical interpretations made from these indices. The statistical modelling approach to construct the latent health factor index (LHFI) was recently developed to express ecological data, collected to construct conventional multimetric health indices, in a rigorous quantitative model that integrates qualitative features of ecosystem health and preconceived ecological relationships among such features. This hierarchical modelling approach allows (a) statistical inference of health for observed sites and (b) prediction of health for unobserved sites, all accompanied by formal uncertainty statements. Thus far, the LHFI approach has been demonstrated and validated on freshwater ecosystems. The goal of this paper is to adapt this approach to modelling estuarine ecosystem health, particularly that of the previously unassessed system in Richibucto in New Brunswick, Canada. Field data correspond to biotic health metrics that constitute the AZTI marine biotic index (AMBI) and abiotic predictors preconceived to influence biota. We also briefly discuss related LHFI research involving additional metrics that form the infaunal trophic index (ITI). Our paper is the first to construct a scientifically sensible model to rigorously identify the collective explanatory capacity of salinity, distance downstream, channel depth, and silt-clay content --- all regarded a priori as qualitatively important abiotic drivers --- towards site health in the Richibucto ecosystem.Comment: On 2013-05-01, a revised version of this article was accepted for publication in PLoS One. See Journal reference and DOI belo

Climate change and Mediterranean seagrass meadows: A synopsis for environmental managers

This synopsis focuses on the effects of climate change on Mediterranean seagrasses, and associated communities, and on the contribution of the main species, Posidonia oceanica, to the mitigation of climate change effects through sequestering carbon dioxide. Whilst the regression of seagrass meadows is well documented, generally linked to anthropogenic pressures, global warming could be a cause of new significant regression, notably linked to the introduction of exotic species, the rise of Sea-Surface Temperature (SST), and relative sea level. Seagrass communities could also be affected by climate change through the replacement of high structural complexity seagrass species by species of lower complexity and even by opportunistic introduced species. Although it is currently very difficult to predict the consequences of these alterations and their cascade effects, two main potential conflicting trends in the functioning of seagrass ecosystems are acceleration of the herbivore pathway or the detritivore pathway. The mean net primary production of the dominant species, Posidonia oceanica, is relatively high and can be estimated to range between 92.5 to 144.7 g C m-2 a-1. Around 27% of the total carbon fixed by this species enters the sedimentary pathway leading to formation, over millennia, of highly organic deposits, rich in refractory carbon. At the Mediterranean scale, the sequestration rate might reach 1.09 Tg C a-1. The amount of this stored carbon is estimated to range from 71 to 273 kg C m-2, which when considered at the Mediterranean scale would represent 11 to 42% of the CO2 emissions produced by Mediterranean countries since the beginning of the Industrial Revolution. The greatest value of the P. oceanica ecosystem, in the context of mitigation of global climate change, is linked to this vast long-term carbon stock accumulated over millennia, and therefore, efforts should be focused on preserving the meadows to keep this reservoir intact

Collaborative database to track Mass Mortality Events in the Mediterranean Sea

Anthropogenic climate change, and global warming in particular, has strong and increasing impacts on marine ecosystems (Poloczanska et al., 2013; Halpern et al., 2015; Smale et al., 2019). The Mediterranean Sea is considered a marine biodiversity hotspot contributing to more than 7% of world\u2019s marine biodiversity including a high percentage of endemic species (Coll et al., 2010). The Mediterranean region is a climate change hotspot, where the respective impacts of warming are very pronounced and relatively well documented (Cramer et al., 2018). One of the major impacts of sea surface temperature rise in the marine coastal ecosystems is the occurrence of mass mortality events (MMEs). The first evidences of this phenomenon dated from the first half of \u201980 years affecting the Western Mediterranean and the Aegean Sea (Harmelin, 1984; Bavestrello and Boero, 1986; Gaino and Pronzato, 1989; Voultsiadou et al., 2011). The most impressive phenomenon happened in 1999 when an unprecedented large scale MME impacted populations of more than 30 species from different phyla along the French and Italian coasts (Cerrano et al., 2000; Perez et al., 2000). Following this event, several other large scale MMEs have been reported, along with numerous other minor ones, which are usually more restricted in geographic extend and/or number of affected species (Garrabou et al., 2009; Rivetti et al., 2014; Marb\ue0 et al., 2015; Rubio-Portillo et al., 2016, authors\u2019 personal observations). These events have generally been associated with strong and recurrent marine heat waves (Crisci et al., 2011; Kersting et al., 2013; Turicchia et al., 2018; Bensoussan et al., 2019) which are becoming more frequent globally (Smale et al., 2019). Both field observations and future projections using Regional Coupled Models (Adloff et al., 2015; Darmaraki et al., 2019) show the increase in Mediterranean sea surface temperature, with more frequent occurrence of extreme ocean warming events. As a result, new MMEs are expected during the coming years. To date, despite the efforts, neither updated nor comprehensive information can support scientific analysis of mortality events at a Mediterranean regional scale. Such information is vital to guide management and conservation strategies that can then inform adaptive management schemes that aim to face the impacts of climate change

European Red List of Habitats Part 1. Marine habitats

The European Red List of Habitats provides an overview of the risk of collapse (degree of endangerment) of marine, terrestrial and freshwater habitats in the European Union (EU28) and adjacent regions (EU28+), based on a consistent set of categories and criteria, and detailed data and expert knowledge from involved countries1. A total of 257 benthic marine habitat types were assessed. In total, 19% (EU28) and 18% (EU28+) of the evaluated habitats were assessed as threatened in categories Critically Endangered, Endangered and Vulnerable. An additional 12% were Near Threatened in the EU28 and 11% in the EU28+. These figures are approximately doubled if Data Deficient habitats are excluded. The percentage of threatened habitat types differs across the regional seas. The highest proportion of threatened habitats in the EU28 was found in the Mediterranean Sea (32%), followed by the North-East Atlantic (23%), the Black Sea (13%) and then the Baltic Sea (8%). There was a similar pattern in the EU28+. The most frequently cited pressures and threats were similar across the four regional seas: pollution (eutrophication), biological resource use other than agriculture or forestry (mainly fishing but also aquaculture), natural system modifications (e.g. dredging and sea defence works), urbanisation and climate change. Even for habitats where the assessment outcome was Data Deficient, the Red List assessment process has resulted in the compilation of a substantial body of useful information to support the conservation of marine habitats

Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia)

Effect of trematode parasites on cockle Cerastoderma edule growth and condition index: a transplant experiment

We quantified the effect of trematode parasites in cockles through a 303 d transplant experiment. Cockles were sampled in 3 different sites on the southwest coast of France characterized by 3 different trematode communities, i.e. Royan (RO): high Meiogymnophallus minutus abundance near cockle heart, South Arguin (SA): high Himasthla interrupta abundance in the mantle margin, and North Arguin (NA): almost free of trematodes. Sampled cockles were individually tagged and placed in different cages at Banc d'Arguin, Arcachon Bay. At the end of the experiment, RO cockles had lost their trematodes, highlighting the fact that trematode lifespan can be short, while SA cockles maintained their trematode load. When cockles were the second intermediate host, there was no effect of site of origin on cockle condition index and survival. The effect on growth rate was mostly due to initial cockle length. Within each treatment, the only significant effect of trematode infection on growth was found for H. interrupta at SA. The 23% growth deficit observed could be due to the disruption of cockle shell synthesis in the mantle margin. During the transplant experiment, cockles were also infected at an exceptionally high rate by Bucephalus minimus, a trematode which invades most of the tissues and uses the cockle as a first intermediate host. Surprisingly, there was an effect on the growth rate and condition index of cockles at only one of the sites under study. This field experiment succeeded in quantifying the moderately negative effect of trematode parasites on the growth and condition of their host and suggested the existence of interactions with as yet unknown factors

Spatial organisation of macrozoobenthic communities in response to environmental factors in a coastal lagoon of the NW African coast (Merja Zerga, Morocco)

Merja Zerga lagoon, located on the Moroccan Atlantic coast, is a site of international value (Ramsar Site) in terms of its ornithological diversity. However, the lagoon is heavily exploited for its clams and fishes. In an effort to further understanding of lagoon ecosystems, and thus to facilitate the management and conservation of their resources, an ecological survey of its benthic component was carried out. Benthos is a valuable food source for birds, fishes and humans. This work involved identifying the macrozoobenthic communities in the lagoon and assessing their spatial distribution. The study was based on monthly sampling of the intertidal zone and seasonal sampling in subtidal zone, over a one-year period. In the intertidal zone, salinity and median diameter and silt content of the sediment exhibited a gradient extending from the entrance to the inner lagoon, according to tidal flow. Sediment grain size characteristics reflected a gradual decrease of tidal currents from the lagoon entrance towards the inner parts of the lagoon, i.e. silt content increased with distance from the entrance. In the subtidal zone, the tidal currents were fairly strong throughout the lagoon, leading to the presence of coats er sediments than in the intertidal zone. Based on these physical, chemical and substratum characteristics, three communities were identified:, (i) Cerastoderma edule and (ii) Scrobicularia Plana communities were located in both the intertidal and subtidal zones; and (iii) a Tapes decussata community that was only found in the subtidal zone. The assemblages in the subtidal zone were more diverse and the mean abundances of the constituent species were higher than in the intertidal zone, which is an interesting feature for a lagoon environment. Communities were distributed along an ecological gradient, without showing a discontinuity or ecotone. The lagoon functioned like an estuary in which the community structure was controlled by edaphic factors in the intertidal zone, and by the hydrological factors in the subtidal zone.La lagune de Merja Zerga, située sur la côte atlantique marocaine, présente un intérêt international (Site Ramsar) pour sa diversité ornithologique. Toutefois, elle est très exploitée pour ses palourdes et ses poissons. Dans le but de bien connaître le fonctionnement de l’écosystème lagunaire pour aider à sa gestion et la conservation de ses ressources, un suivi écologique a été mené sur l’écosystème benthique, compartiment–proie essentiel pour les oiseaux et pour l’homme. Ce travail vise à identifier les communautés macrozoobenthiques et à préciser leur répartition spatiale. L’étude est basée sur un échantillonnage mensuel de la zone intertidale et sur des prélèvements saisonniers de la zone subtidale, sur une période d’une année. En zone intertidale, la salinité, la médiane granulométrique et les taux de pélites présentent des gradients allant de l’ouverture vers l’intérieur de la lagune, en suivant le flot engendré par la marée. Les caractéristiques granulométriques traduisent l’affaiblissement progressif des courants de marée de l’aval à l’amont, i.e. les teneurs de pélites augmentent en s’éloignant de l’ouverture. En zone subtidale, les courants de marée restent assez forts tout au long de la lagune, ce qui conduit à la présence de sédiments plus grossiers qu’en zone intertidale. Selon ce schéma de structure physico-chimique et édaphique, trois communautés sont identifiées : les communautés à (i) Cerastoderma edule et à (ii) Scrobicularia plana, localisées à la fois en zones intertidale et subtidale et (iii) une communauté à Tapes decussata, présente uniquement en zone subtidale. Les assemblages sont plus diversifiés en zone subtidale et les abondances moyennes des espèces y sont plus fortes qu’en zone intertidale, ce qui constitue une originalité pour un milieu lagunaire. Les communautés se distribuent le long d’un gradient écologique sans stade de transition ou écotone. La lagune fonctionne selon un modèle estuarien dans lequel la structure des communautés est contrôlée par les facteurs édaphiques en zone intertidale et par les facteurs hydrologiques en zone subtidale

Impact of shorebird predation on intertidal macroinvertebrates in a key North African Atlantic wintering site: an experimental approach

Shorebirds, as migratory aquatic birds and top predators in intertidal  ecosystems, can be affected by global environmental changes and  escalations in local impacts on coastal lagoons and estuarine trophic networks. Many shorebirds winter in North African Atlantic coastal sites, most likely because these locations provide constant and reliable food supplies with less energy costs in comparison with the wintering sites of northern Europe. Although more information is available for other important  southern coastal sites (e.g. Saharan Atlantic coastal desert and Guinean mangroves coast), very little information is available for the North African Atlantic coast. Here, we focus on the impact of shorebird predation on benthic macroinvertebrates in a major wintering site in this area—Sidi Moussa coastal lagoon, Morocco—using an exclosure experiment. For most of the macroinvertebrate species there was no significant effect of the exclusion of shorebird predation. Overall, our results do not show evidence that predation by shorebirds influenced the overall standing biomass of the benthic community. This may indicate that the benthic productivity is high enough to provide constant and reliable food supplies for non-breeding shorebirds.Keywords: biomass, carrying capacity, benthic  macroinvertebrates, exclosure experiment, migration, predator–prey  interactions, Sidi Moussa lagoon, waterbird