Record-sized female smooth-hound ( Mustelus sp.) captured in Corsican waters and preliminary observations on feeding on the invasive blue crab Callinectes sapidus

This study investigates the effects of trap selectivity of various mesh size on escape success of the blue crab (Callinectes sapidus). The study was carried out Camlik Lagoon of Yumurtalik Gulf in the Mediterranean Sea and total of 1051 blue crabs were caught by rectangular baited trap. Using traps constructed with 30, 35, 40, 45 and 50 mm square mesh the proportion of crabs escaping through each mesh size was measured for each half centimetre carapace width (CW) class. A logistic model was fitted to the size frequency data of the retained and escaped blue crabs for each mesh size in the experiment. L50 and selection range (SR) for the 30, 35, 40, 45 and 50 mm (bar length) square meshes tested in this study was 8.47 cm and 0.85 cm; 9.31 cm and 0.39 cm; 10.40 cm and 0.31 cm; 11.72 cm and 1.17 cm; 13.17 cm and 0.89 cm respectively. The 50 mm square mesh of the trap showed relatively better selectivity considering the size at 50% sexual maturity of blue crab Callinectes sapidus, and the high rate of immature escapers. Keywords: Blue crab Callinectes sapidus; Trap; Size selectivity; Mediterranean Sea

1 - Lagoons are habitat islands in the coastal landscapes characterised by both among ecosystems heterogeneity, due to different terrestrial-freshwater, freshwater-marine interfaces, and within ecosystem heterogeneity, due patchy spatial and temporal distribution of biotic and abiotic components. 2 - Here, we investigate to what extent biodiversity in lagoon ecosystems is affected by these different sources of heterogeneity and which are the implication of the different sources for biodiversity management at the local scale of each single lagoon. 3 - To this aim, we focused on benthic macro-invertebrates using two sources of data: literature data on a sample of 26 Italian lagoons, and synoptically collected data on a sample of 10 lagoons in Eastern Mediterranean and Black Sea. The first data set allowed inference on the among ecosystem heterogeneity and the second on the within ecosystem heterogeneity at the scale of habitat type. Therefore, a hierarchical scaling of biodiversity in lagoon ecosystem is globally addressed. 4 - Results show that the largest component of biodiversity in lagoon ecosystems is due to the differences among ecosystems. Dissimilarity among the taxonomic composition of macro-invertebrate guilds of the Italian lagoons was close to 90%. Difference in habitat type within lagoon ecosystems also affect biodiversity but less than among ecosystem differences; average dissimilarity among habitat types at the ecosystem level was 66.4±10.6 and within habitat types 49.67±6.0. 5 - The analysis suggest that most of biodiversity on benthic macro-invertebrate guilds in the Mediterranean and Black Sea is maintained at the Ecoregional scale, being realised only at a small extent at every local ecosystems. This finding stress the importance of a transnational governance of coastal ecosystem health in order to preserve biodiversity at any local scale within the EcoRegion. 6 - A role of land use management in lagoon watersheds was also emphasised and scaled up with respect to biological interactions acting at the very local scale.

Cross-community scaling relationships (CCSRs), which result from individual density scaling with average individual body size at guild and community levels, enable investigation of energy constraints at high levels of the ecological hierarchy. Here, we studied cross-community scaling relationships in benthic macroinvertebrate guilds in 15 Mediterranean and Black Sea lagoon ecosystems characterized by strong habitat heterogeneity and high energy density, using data already available in the LifeWatch-Italy data portal. The study sought to describe CCSR patterns in lagoon ecosystems, analyzing their variability across habitat and ecosystem types and evaluating the relative influence on individual body size, macroinvertebrate guild density, or both, of proxies of ecosystem properties, including physiographic characteristics and external disturbance, acting as potential drivers. Significant CCSRs were observed in benthic macroinvertebrate guilds in Mediterranean and Black Sea lagoons. They were characterized by high internal variability and slopes less negative than the metabolic scaling theory expectation (b = −0.75), ranging between b = −0.27 and b = −0.50. Lagoon ecosystem typology, inter-lagoon variation, and ecosystem properties explained part of the variation in internal CCSRs, while habitat variation and intra-ecosystem habitat heterogeneity did not show any influence. CCSR intercepts expressing macroinvertebrate-specific densities showed patterns of variation that were consistent with those of proxies of ecosystem energetics and parsimony, such as eutrophication, chemical and physical disturbances, and openness. These relationships highlight the relevance of CCSRs, which enable inferences on the properties, functioning, and ecological status of ecosystems from simple analyses of community structure.

Invasive non-native crustaceans are a biodiversity and management concern in the Mediterranean Sea. The Atlantic blue crab (Callinectes sapidus) was first recorded in the Mediterranean Sea in 1949, but may have arrived as early as in the 1930’s. Blue crabs in the Mediterranean Sea are of concern due to their presumed potential for negative consumptive and competitive interactions with native fauna. The aim of this study was to provide a first assessment of the trophic ecology of non-native blue crab in the Northern Aegean Sea using stable carbon (δ13C) and nitrogen isotope (δ15N) analysis. We found limited isotopic niche overlap between blue crabs and seven native species examined at Gokceada Island in April, June, and August of 2017. In addition, the range of calculated trophic positions of blue crabs at Gokceada Island (2.0 to 4.4), while broad, is in general agreement with prior studies in both native and non-native ranges. We also observe that trophic position declined and the relative importance of pelagic carbon sources to blue crabs increased from April to August. However, we also found that differing assumptions as to the number and type of food web baselines and trophic discrimination factors led to differing estimates of trophic position in blue crabs at Gokceada Island by as much as one to two trophic levels. These methodical differences make it challenging to directly compare results within and between studies, and thus limit our ability to assess negative consumptive and competitive interactions of invasive blue crab with native coastal species in the Mediterranean Sea.

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The blue crab Callinectes sapidus is a portunid brachyuran native of the Atlantic coasts of America. In the last decades, the species has greatly expanded its range in invaded areas, currently including the Atlantic coasts of Morocco, the Mediterranean Sea, the Black Sea as well as the eastern Atlantic coasts of Europe from Portugal to France, Belgium, and Germany. In the present study, several specimens of C. sapidus were collected in May, June and July 2021 in the Stagnone di Marsala, a semi-enclosed basin located in the north-western coast of Sicily (southern Italy, Mediterranean Sea) characterized by low hydrodynamics and water exchange with the adjacent open sea and high salinity conditions. Juveniles at different instar stages and ovigerous females were repeatedly captured, suggesting the presence of an established population of the blue crab, despite the peculiar environmental conditions characterizing the basin. These findings are discussed in the context of the current expansion of the species along the African coasts of the Mediterranean Sea.

IntroductionNon-native species are widely recognized as threats to biodiversity, ecosystems, and the services they provide to humans. The Mediterranean Sea has a high biodiversity of endemic species and is a hot spot of biological invasions. One of the most recent threats to Mediterranean ecosystems is the invasion of the Atlantic blue crab Callinectes sapidus.MethodsThe occurrences of the crab throughout the Mediterranean coastline were indexed from citizen science through the Global Biodiversity Information Facility. Using spatial analysis and linear mixed models, we investigated geomorphology (i.e., water depth and coastal wetlands extension), water physical variables (i.e., salinity and winter and summer water temperature), water quality variables (i.e., chlorophyll-a, nitrate and orthophosphate) and anthropogenic factors (i.e., ship density and population size) potentially affecting the blue crab occurrence along the coast.ResultsOur results showed that nitrate, as an indicator of riverine nutrient loading, and water depth, as an indicator of slope of the bottom, were the most influential variables in explaining the occurrences of blue crabs. Water temperature and salinity had lesser impacts; anthropogenic factors, such as the density of commercial marine traffic and human population size had no effect on blue crab occurrence.DiscussionThese results sug gest that benthic primary production and shallow water drive blue crab occurrences along the Mediterranean coasts. Even considering data limitations and gaps, our large-scale findings contribute to a broader understanding of the factors that drive blue crab invasion success which, in turn, can inform management actions and outline research needs.

Decomposition processes are a major source of energy in lagoon ecosystems, but compared to primary production, little quantitative information is available on their relative importance for energy pathways within lagoon food webs. Here, the ability of cross-community scaling relationships (CCSRs) to describe energy pathways in macroinvertebrate guilds from size-specific density estimates was tested in order to determine whether CCSRs distinguish between i. predators and prey guilds in energetic terms, ii. suspension and deposit feeders in terms of their energy sources, iii. deposit feeder sub-guilds (i.e. scrapers/shredders and gathering collectors), and iv. phyto-benthic habitats in terms of their influence on energy pathways. CCSRs differentiated predator from prey guilds, with the size-specific density of prey being one order of magnitude higher than that of predators, and deposit from suspension feeder guilds, to a similar degree. CCSRs differentiated vegetated from non-vegetated benthic habitats, with higher size-specific density in the former than in the latter, while they did not differentiate large- from small-particle feeders. Based on simple data collection and widely available data on 15 Mediterranean and Black Sea lagoons, CCSRs seem to be able to quantitatively describe energy pathways in benthic macroinvertebrate communities, expanding our knowledge of biodiversity drivers in lagoon ecosystems.

The blue crab Callinectes sapidus (Rathbun, 1896) is one of the most invasive species in the Mediterranean Sea. Understand how the populations are maintained and how the environment is driving the populations in the areas invaded is the key to an effective future management. This current study is presenting a monthly long-term monitoring of the blue crabs' population structure, body size, sexual maturity, reproduction periods and fecundity, and their relationships with environmental factors in a saltmarshes system in Italy. During winter, high densities (15 ± 8 ind m-2) of early juveniles (< 2 cm) were observed, and their numbers decreased due the population growth until summer. The size-spectra showed that across different temperature (18-26°C) and salinity (24-40 psu) gradients, the growth period for males is faster than for females. Based on abdominal analysis, sexual maturity was defined at ∼12 cm for males and females but the population was in favor of males that were more than 66% of the time mature throughout the year. Copulations periods were identified between spring and autumn when more than 50% of females were matures, and ovigerous females' migrations were observed in late summer. Our study expand our understanding of how the environment interacts to effect physiological and biological processes of alien species and improve our ability to make predictions of how environmental change the distribution of the alien species in the future. Based on our results, we also discuss which population control strategy would be most effective based on the data available in the literature.

GIS-based multi-criteria site selection for zebra mussel cultivation: Addressing end-of-pipe remediation of a eutrophic coastal lagoon ecosystem

The impact of mining activities on the hypersaline Mar Menor lagoon

Rapid assessment of non-indigenous species in the era of the eDNA barcoding: A Mediterranean case study

Lagoons are fragile marine ecosystems that are considerably affected by anthropogenic pollutants. We performed a spatiotemporal characterization of the microbiome of two Moroccan lagoons, Marchica and Oualidia, both classified as Ramsar sites, the former on the Mediterranean coast and the latter on the Atlantic coast. We investigated their microbial diversity and abundance using 16S rRNA amplicon- and shotgun-based metagenomics approaches during the summers of 2014 and 2015. The bacterial microbiome was composed primarily of Proteobacteria (25–53%, 29–29%), Cyanobacteria (34–12%, 11–0.53%), Bacteroidetes (24–16%, 23–43%), Actinobacteria (7–11%, 13–7%), and Verrucomicrobia (4–1%, 15–14%) in Marchica and Oualidia in 2014 and 2015, respectively. Interestingly, 48 strains were newly reported in lagoon ecosystems, while eight unknown viruses were detected in Mediterranean Marchica only. Statistical analysis showed higher microbial diversity in the Atlantic lagoon than in the Mediterranean lagoon and a robust relationship between alpha diversity and geographic sampling locations. This first-ever metagenomics study on Moroccan aquatic ecosystems enriched the national catalog of marine microorganisms. They will be investigated as candidates for bioindication properties, biomonitoring potential, biotechnology valorization, biodiversity protection, and lagoon health assessment.

Sea temperature change in the Mediterranean, Marmara and Black Sea coasts of Turkey and its biodiversity effects are investigated. The surface sea water temperatures of the Mediterranean, Marmara and Black Sea region of Turkey for last 41 years showed increased trends in Mediterranean Sea (Iskenderun, Mersin and Antalya), Marmara Sea (Istanbul) and Black Sea (Samsun). The number of Indo-Pacific species is getting rapidly increased for the last decade that caused increased invasion of the Indo-Pacific species and significant shift of biodiversity in Turkish Seas. This settlement process is probably accelerated or facilitated by global climate change and overfishing of native species. Nowadays, the occurrence of Atlantic-Mediterranean (Lithognathus mormyrus, Serranus hepatus and Callinectes sapidus) and Indo-Pacific (Stephanolepis diaspros, Lagocephalus spadiceus) originated species in the Marmara and Black Seas can also be an important indicator of the process of Mediterranization of the Marmara and Black Seas.

Sand is a useful resource for the development of any society. As such, the issues related to its extraction are everywhere present in Benin, especially in the southern part of the country. For the purposes of eventually characterizing those issues, the present study is undertaken with a focus on inventorying estuarine and lagoonal ecosystems which are subjected to sand mining in southern Benin. The study area covers both the Eastern Complex and the Western Complex. The Eastern Complex includes the Porto-Novo Lagoon and the Oueme River delta; while the Western Complex includes the Coastal Lagoon, the Aheme Lake along with its channels, and the Mono Basin. The method used in this study is a systematic inventorying of all known and documented sites as kept on record with relevant state offices in charge of the management of those resources. Then, the data were completed by combing the whole area for direct census observations and field interviews with stakeholders. All inventoried sites have been geo-referenced using a GARMIN GPS and their surface areas have been established. To date, 43 sand-mining sites have been identified, of which 29 are located in the Oueme Delta and in the Porto-Novo Lagoon, 8 are in the Coastal Lagoon, and 6 are in the Aheme Lake and its channels as well as in the Mono River basin. The areas are small in the Oueme Delta, where extraction is mostly manual, but get to be more than 89-ha wide in other places such as the Coastal Lagoon where the process is rather mechanized.