Phylogeography of the Atlantic Blue Crab Callinectes sapidus (Brachyura: Portunidae) in the Americas versus the Mediterranean Sea: Determining Origins and Genetic Connectivity of a Large-Scale Invasion.

The American blue crab Callinectes sapidus is a particularly successful invader in estuarine ecosystems worldwide. Despite increasing awareness of its potential harm, the invasion history and underlying genetic diversity of this species within the Mediterranean Sea remain unknown. This study constitutes the first large-scale approach to study phylogeographic patterns of C. sapidus in Europe, facilitated by the first comparison of all currently available COI sequence data. For this investigation, 71 individuals of C. sapidus were newly analyzed and the entire COI gene was sequenced and used for a comparative phylogeographic analyses. For the first time, two separately used adjacent regions of this gene were combined in a single dataset. This allowed emphasizing the prevalence of three geographically defined lineages within the native range: (1) eastern North America, including the Gulf of Mexico, (2) the Caribbean, and (3) Brazil. New data from the Mediterranean reveal that non-native populations of C. sapidus are characterized by a conspicuously low genetic diversity (except for Turkey, where stocking took place), and that there is surprisingly low connectivity among established populations. The occurrence of strong genetic bottlenecks suggests few founder individuals. This confirms that, even under a scenario of restricted large-scale gene flow, a very limited number of invasive individuals is sufficient for a massive impact.

An individual-based dataset of carbon and nitrogen isotopic data of Callinectessapidus in invaded Mediterranean waters.

BACKGROUND: The characterisation of functional traits of non-indigenous and invasive species is crucial to assess their impact within invaded habitats. Successful biological invasions are often facilitated by the generalist diet of the invaders which can modify their trophic position and adapt to new ecosystems determining changes in their structure and functioning. Invasive crustaceans are an illustrative example of such mechanisms since their trophic habits can determine important ecological impacts on aquatic food webs. The Atlantic blue crab Callinectessapidus is currently established and considered invasive in the Mediterranean Sea where it has been recorded for the first time between 1947 and 1949. In the last decade, the blue crab colonised most of the eastern and central Mediterranean Sea and the Black Sea and it is currently widening its distribution towards the western region of the basin. NEW INFORMATION: Stable isotope analysis is increasingly used to investigate the trophic habits of invasive marine species. Here, we collated individual measures of the blue crab δ13C and δ15N values and of its potential invertebrate prey into a geo-referenced dataset. The dataset includes 360 records with 236 isotopic values of the blue crab and 224 isotopic data of potential prey collected from five countries and 12 locations between 2014 and 2019. This dataset allows the estimation of the trophic position of the blue crab within a variety of invaded ecosystems, as well as advanced quantitative comparisons of the main features of its isotopic niche.

Beclomethasone dipropionate and sodium cromoglycate protect against airway hyperresponsiveness in a human ex vivo model of cow's milk aspiration.

BACKGROUND: Recurrent cow's milk (CM) aspiration is often associated with gastroesophageal reflux in infants and toddlers and it seems to be implicated in the etiology of different inflammatory lung disorders. This study aimed to investigate ex vivo the impact of CM aspiration on human airways and whether treatment with beclomethasone dipropionate (BDP) or sodium cromoglycate (SCG) may prevent the potential CM-induced airway hyperresponsiveness (AHR). METHODS: Human isolated bronchi were contracted by electrical field stimulation (EFS10Hz) to mimic the contractile tone induced by the parasympathetic activity and challenged with CM, fat/lactose-free CM, or human breast milk (HM). The effect of pre-treatment with beclomethasone dipropionate (BDP) and sodium cromoglycate (SCG) was also investigated on the AHR induced by CM. RESULTS: After a 60 min-challenge with CM 1:10 v/v and fat/lactose-free CM 1:10 v/v, ASM significantly (P â€‹< â€‹0.05) increased compared to control (+67.04 â€‹± â€‹17.08% and +77.91 â€‹± â€‹1.34%, respectively), a condition that remained stable for 150 â€‹min post-treatment, whereas HM did not alter ASM contractility. BDP 1 â€‹µM and 10 â€‹µM significantly (P â€‹< â€‹0.05) reduced the AHR elicited by CM (-52.49 â€‹± â€‹10.97% and -66.98 â€‹± â€‹7.90%, respectively vs. control). At the same manner, SCG 1 â€‹µM and 10 â€‹µM significantly (P â€‹< â€‹0.05) inhibited the CM-induced AHR (-59.03 â€‹± â€‹9.24% and -73.52 â€‹± â€‹7.41%, respectively vs. control). CONCLUSION: CM induces AHR in human ASM by eliciting an increased parasympathetic contractile response. Preventive treatment with nebulized SCG may be indicated in infants or toddlers fed with CM, rather than with BDP due to a superior safety profile.

Effects of environmental variables on the distribution of juvenile cubomedusae Carybdea marsupialis in the coastal Western Mediterranean.

Relationships between environmental factors and oscillations in jellyfish abundance, especially in the early life stages, could help to interpret past increases and also predict scenarios in a changing future. For the first time, we present cubozoan spatial and temporal distributions in the earliest stages and their relationships with different factors. Abundances of Carybdea marsupialis medusae showed high interannual variability from 2008 to 2014 along the Dénia coast (SE Spain, W Mediterranean). During 2015, samples were collected from 11 beaches along 17 km of coastline, 8 times from January to November in order to determine the effects of environmental factors on the distribution of juvenile C. marsupialis. Juveniles (≤ 15 mm diagonal bell width) were present from May to July, with more sampled near shore (0-15 m). Most of them occurred in June when their numbers were unequal among beaches (average 0.05 ind m-3, maximum 6.71 ind m-3). We tested distributions of juveniles over time and space versus temperature, salinity, nutrients (N, P and Si), chlorophyll-a (Chl-a), and zooplankton abundance. Temperature and cladocerans (zooplankton group) were significantly positively correlated with juvenile distribution, whereas Chl-a concentration was weakly negative. By contrast, in 2014, high productivity areas (Chl-a and zooplankton) overlapped the maximum adult abundance (5.2 ind m-3). The distribution of juveniles during 2015 did not spatially coincide with the areas where ripe adults were located the previous year, suggesting that juveniles drift with the currents upon release from the cubopolyps. Our results yield important insights into the complexity of cubozoan distributions.

The Atlantic blue crab Callinectes sapidus in southern European coastal waters: Distribution, impact and prospective invasion management strategies.

The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the Mediterranean and in the Black Sea. An overview of the occurrence, abundance, and ecological impact of the species in southern European waters is provided; additionally, we present a pragmatic assessment of its management scenarios, explicitly considering the dual nature of C. sapidus as both an invasive species and a fishery resource. We emphasise that the ongoing expansion of C. sapidus in the region may represent a stimulating challenge for the identification and implementation of future strategies in the management of invasive crustaceans. The impact of the invader could be converted into an enhancement of the services delivered by southern European coastal ecosystems, while mitigation costs could be transformed into profits for local populations.

Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) in the NW Mediterranean Sea on water column and sediment.

This study examined the effects of organic enrichment on water column, sediments and macrofauna caused by a fish farm in the Mediterranean Sea. Samples were collected on four sampling campaigns over a one-year cycle. Significant differences were found in the water column in dissolved oxygen, dissolved inorganic nitrogen, phosphate and total phosphorus concentrations between the fish farm and the control. The increase in the dissolved inorganic nitrogen and phosphate concentrations at the fish farm modified the stoichiometric ratios between nutrients, with silicate acting as limiting nutrient at the fish farm 11% more than at the control. Nevertheless, chlorophyll a concentration in the water column was higher at the control station, probably due to the fouling of the underwater fish farm structures. Significant differences were found in sediment concentrations of organic matter, total phosphorus and redox potential between the fish farm and the control. The Canonical Correlation Analysis indicated that organic matter, total phosphorus, redox potential and% of gravels accounted for 68.9% of the total variance in the species data. Changes were observed in macrofauna, with a decrease in number of species and up to a nine-fold increase in abundance with respect to the control.