Large scale patterns of trematode parasites communities infecting Cerastoderma educe along the Atlantic coast from Portugal to Morocco

In this study, spatial sampling was performed from north Portugal to south Morocco to analyse trematode communities of the widespread bivalve Cerastoderma edule, host of several trematode species. From the twelve trematode species found in this study, nine were present in multiple aquatic systems demonstrating high trematode dispersal ability, driven by the presence of all hosts. Multivariate analysis related to trematode communities in cockles clustered: 1) Portuguese aquatic systems influenced by cold waters, leading to low trematode abundance; 2) coastal systems characterized by dominance of trematode Parvatrema minutum and muddy sediments; 3) lagoons (or bays) with high oceanic influence and high trematode diversity. These findings suggested that, besides host species presence, temperature is an important trigger for parasite infection, with coastal upwelling operating as a shield against trematode infection in Portugal and masking latitudinal gradients. Results highlighted the possible consequences of thermal modification mediated by oceanographic global circulation change on cockle populations.publishe

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

Impacts of the non-indigenous seaweed Rugulopteryx okamurae on a Mediterranean coralligenous community (Strait of Gibraltar): The role of long-term monitoring

The Mediterranean is one of the most biodiverse and anthropogenically impacted seas and the coralligenous is one of its most diverse habitats. Its presence is indicative of well-preserved areas and its associated species are considered among the best bioindicators for monitoring nearshore rocky habitats. This study aims to report the temporal fluctuations of the coralligenous community in the marine protected area of Jbel Moussa (Strait of Gibraltar) in a period concomitant with the rapid expansion of the non-indigenous species Rugulopteryx okamurae (E.Y.Dawson) I.K.Hwang, W.J.Lee & H.S.Kim in the area. From year 2015 to 2019, an area covering 36 m2 of the coralligenous habitat was monitored across three sites, including temperature logs from 2017 to 2019. After its first record in the area in 2017, R. okamurae became the most abundant species in only one year, followed by a change in the coralligenous community structure and a regression of the bioindicator species Paramuricea clavata (Risso, 1826) and Mesophyllum expansum (Philippi) Cabioch & M.L.Mendoza. These species are sensitive to increases in water temperature and were already under a gradual regression due to anthropogenic disturbances and previous biological invasions, all of which could have reduced niche competition in the area and favoured the impacts caused by R. okamurae in the area. Results highlight the need of a rapid administrative response to increase mitigation efforts on this protected habitat. Due the potential expansion of this non-indigenous invasive species to the Mediterranean Sea, the present study could provide valuable information for future monitoring, conservation and management actions.SPA/RAC–UN Environment/MAP MoU n◦ 60_SPA/RAC_201

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

Population genetics of Bursatella leachii (De Blainville, 1817) and implications for the origin of the Mediterranean population

Abstract The sea hare Bursatella leachii (de Blainville 1817) (Mollusca: Gastropoda: Heterobranchia: Aplysiidae) is a pantropical sea slug that has colonized the Mediterranean Sea in modern times. Because the initial records in the non-native range started in the Eastern Mediterranean, and its pattern of spread was relatively consistent with those observed in well-known Lessepsian invaders, B. leachii is commonly considered to be a migrant from the Red Sea. In this study, we investigate for the first time the origin of the Mediterranean populations of B. leachii inferring their population structure and assessing relatedness levels of different regional populations. Sequence data from the cytochrome oxidase I were used to conduct population genetic analyses on this species, particularly by investigating the genetic structure of Atlantic, Mediterranean, and Indo-Pacific populations. Our results confirm that B. leachii is a truly pantropical species which displays geographic structure among major ocean basins. More importantly, sequenced Mediterranean and Atlantic animals share similar or identical haplotypes, which are distinct in at least 5 substitutions from haplotypes recovered from Indo-Pacific specimens. The results suggest that the Mediterranean population of B. leachii here examined probably have an Atlantic origin, and for the first time casts doubts on the assumed primary pathway of migration into the Mediterranean Sea

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

Action plan for the conservation of habitats and species associated with seamounts, underwater caves and canyons, aphotic hard beds and chemo-synthetic phenomena in the Mediterranean Sea (Dark Habitats action plan)

Dark habitats are environments where the luminosity is extremely weak, or even absent (aphotic area) leading to an absence of macroscopic autochthonous photosynthesis. The bathymetric extension of this lightless area depends to a great extent on the turbidity of the water and corresponds to benthic and pelagic habitats starting from the deep circa-littoral. Caves which show environmental conditions that favour the installation on of organisms characteristic of dark habitats, are also taken into account. Dark habitats are dependent on very diverse geomorphological structures (e.g. underwater caves, canyons, slopes, isolated rocks, abyssal plains, cold seeps, brine anoxic lakes, hydrothermal springs and seamounts). Dark habitats represent outstanding and potential ecosystems with regard to their: Frailty and vulnerability to any land-based pressure Play an important part in the way the Mediterranean ecosystem functions, insofar as they constitute the main route for transferring matter between the coast and the deep sea Considered as biodiversity hotspots and recruiting areas forming a veritable reservoirs of knowledge and biodiversity Natural habitats that come under Habitat Directive on the conservation of natural habitats and of wild fauna and flora and appear as such as priority habitats requiring protection (Directive 92/43). A certain number of underwater caves enjoy protection status because they fall within the geographical boundaries of Marine Protected Areas (MPAs) Understanding of these functions is necessary for a better understanding and management of the biodiversity of Mediterranean coastal zones and continental shelf.peer-reviewe

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

Three main stressors acting on the Ria Formosa lagoonal system (Southern Portugal): physical stress, organic matter pollution and the land–ocean gradient

During the last 15 years of the 20th century, several researchers carried out extensive sampling of benthic macrofauna communities in the Ria Formosa lagoon. The main objective of this paper is to discern the main communities of benthic fauna of the Ria Formosa and the leading stressors that limit them based on this large data set. The high species richness and high diversity values observed at most of the stations or groups of stations indicate a good ecological status, with the exception of the sewage-impacted areas and the physically stressed areas. It was possible to define three main stressors acting on the Ria Formosa. The most important is the physical stress imposed by the limited water renewal in some areas of the Ria Formosa. The second is the nutrient and organic matter pollution that is limited to the vicinity of the sewage outfall stations and to some locations of the Ria Formosa. This is due to the dual effects of the low residence time of water, but also due to a degradation of water quality in places of relatively restricted water circulation but with high primary production, symptoms of eutrophication. The third stressor is the natural land-ocean gradient, denoting the influence of seawater exchanges and emersion time, attenuated by the high water exchange rates of Ria Formosa. It was possible to differentiate the anthropogenic stress from the natural physical stress through the application of multivariate analysis. However, both structural (species richness and diversity indices) and functional indicators (trophic composition) indicate the same trend - low species richness, low diversity indices, and a community dominated by detritivores species at the locations characterized by high anthropogenic impact or by physical stress. The physically stressed areas were dominated by chironomid larvae and hydrobiid gastropods and the most polluted areas were dominated by oligochaetes, mainly tubificids