The Atlantic blue crab Callinectes sapidus spreading in the Tyrrhenian sea: evidence of an established population in the Stagnone di Marsala (Sicily, southern Italy)

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

Variation in the stable isotope trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766) from two Mediterranean sites: insights from a global meta-analysis

A direct consequence of sea warming is the shift in the distribution range of thermo-tolerant species that have the potential to determine novel inter-specific interactions, ultimately altering food web structures and ecosystem processes. In this study, we investigated the trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766), a pelagic predator that has recently expanded its distribution in the Mediterranean basin and for which scant information is available on its functional role in recently-colonised areas. Nitrogen and carbon stable isotopes were determined in muscle tissues of bluefish specimens collected in south-east Italy in the Gulf of Taranto (NW Ionian Sea) and in the Strait of Otranto (SW Adriatic Sea) at two coastal sites showing contrasting oceanographic conditions. The bluefish trophic position (TP) was estimated using locally abundant forage fish species as isotopic baselines. The results indicated for bluefish from the Strait of Otranto a TP value of 5.1, significantly higher than that determined in the Gulf of Taranto (4.2), and exceeding stomach content-based estimations reported by the online database FishBase and by literature sources. A synthesis of 30 publications reporting isotopic data for the bluefish and its potential prey at a global scale indicated that the species’ trophic position varied considerably between 2.7 and 5.2. The observed variability depended on location and on the baseline species used in the estimations. Yet, a significant difference in trophic position was observed for bluefish from transitional and inshore environments as compared with offshore areas, mirroring the results obtained from the Gulf of Taranto and the Strait of Otranto. The findings of the study highlight the high trophic plasticity characterizing the bluefish in recently colonized areas, suggesting that it may play a key role in facilitating the expansion of its distribution range. However, additional investigations are essential to provide an advanced resolution of the bluefish functional role in Mediterranean coastal food webs

Isotopic Niche and Trophic Position of the Invasive Portunid Portunus segnis Forskål, (1775) in Elounda Bay (Crete Island, Eastern Mediterranean)

There is a growing recognition that an advanced understanding of the trophic characteristics of an invasive consumer can provide important information on its ecological impact. In recent years, the blue swimming crab Portunus segnis, one of the earliest Lessepsian invaders, has considerably expanded its distribution range in the Mediterranean Sea, yet, its trophic habits in invaded areas remain scarcely investigated. In this study, we used carbon and nitrogen stable isotopes analysis (SIA) to determine the trophic position and isotopic niche of the crab compared with other representatives of the flora and fauna occurring in Elounda Bay (Crete). P. segnis showed a trophic position of 3.9, higher than the values determined by SIA or conventional gut content analysis in other areas of the Mediterranean Sea or in the native range. Crab specimens showed a high inter-individual variability in both delta C-13 and delta N-15 values; further analysis indicated negligible differences in the isotopic niche of adult males and females. Conversely, delta N-15 values were significantly related to the size of the specimens, ultimately suggesting an ontogenetic dietary shift. This study represents the first attempt to characterize the trophic habits of the blue swimming crab in the context of an invaded food web and may contribute to the implementation of long-term management strategies of control and mitigation of its ecological impact

An individual-based dataset of carbon and nitrogen isotopic data of Callinectes sapidus in invaded Mediterranean waters

[EN] 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 Callinectes sapidus 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 d C and d N 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.Di Muri, C.; Rosati, I.; Bardelli, R.; Cilenti, L.; Veli, DL.; Falco, S.; Vizzini, S.... (2022). An individual-based dataset of carbon and nitrogen isotopic data of Callinectes sapidus in invaded Mediterranean waters. Biodiversity Data Journal (Online). 10:1-12. https://doi.org/10.3897/BDJ.10.e775161121

Erratum to: Integrated molecular dissection of the epidermal growth factor receptor (EGFR) oncogenic pathway to predict response to EGFR-targeted monoclonal antibodies in metastatic colorectal cancer

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First report on two loggerhead turtle (Caretta caretta) nests in the Aeolian Archipelago (Southern Italy)

The Aeolian Archipelago (Southern Tyrrhenian Sea, Italy) hosts important foraging/overwintering habitats for Mediterranean loggerhead sea turtles (Caretta caretta), although nesting sites have never been documented. This study reports the data of two nesting events occurred in summer 2019 at Stromboli and Lipari islands. A hatchling success of 20.69 % (18 hatchlings from 87 eggs) was recorded at Stromboli, while a complete hatchling unsuccess characterised the Lipari nest, where 111 eggs were deposited. Data acquired during the monitoring of the nests suggest that combined factors, mainly temperature, beach morphology, and sand composition, could be the causes for the low success of these nesting events

Sensitivity to Entrectinib Associated with a Novel LMNA-NTRK1 Gene Fusion in Metastatic Colorectal Cancer

In metastatic colorectal cancer (CRC), actionable genetic lesions represent potential clinical opportunities. NTRK1, 2, and 3 gene rearrangements encode oncogenic fusions of the tropomyosin-receptor kinase (TRK) family of receptor tyrosine kinases in different tumor types. The TPM3-NTRK1 rearrangement is a recurring event in CRC that renders tumors sensitive to TRKA kinase inhibitors in preclinical models. We identified abnormal expression of the TRKA protein in tumor and liver metastases of a CRC patient refractory to standard therapy. Molecular characterization unveiled a novel LMNA-NTRK1 rearrangement within chromosome 1 with oncogenic potential, and the patient was treated with the pan-TRK inhibitor entrectinib, achieving partial response with decrease in hepatic target lesions from 6.8 and 8.2cm in longest diameter to 4.7 and 4.3cm, respectively. To our knowledge, this is the first clinical evidence of efficacy for therapeutic inhibition of TRKA in a solid tumor, illuminating a genomic-driven strategy to identify CRCs reliant on this oncogene to be clinically targeted with entrectinib

The spread of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in the Mediterranean Sea: analysis of environmental and trophic niche and metal levels at different spatial scales

Biological invasions are globally acknowledged as one of the major causes of biodiversity loss. Considering the urgency of understanding what are the effects of biological invasions on recipient ecosystems, this research focuses on the Atlantic blue crab Callinectes sapidus, one of the most successful invaders of Mediterranean coastal ecosystems. First, a general assessment of the overlap of the Grinnellian niche of the species in native and invaded ranges was carried out to verify whether the blue crab maintained the characteristics of its climatic niche when establishing in invaded areas (niche conservatism hypothesis) or, alternatively, it adapted to the specific abiotic characteristics of recipient environments (niche shift hypothesis). The results showed a low degree of niche overlap between native and invaded ranges, highlighting that a niche shift occurs and indicating that the species not only colonized the areas where the oceanographic conditions reproduced those occurring in native ranges, but was also able to adapt to novel environmental contexts occurring in the Mediterranean Sea. Subsequently, a study of a newly recorded population within the Stagnone di Marsala, a marine coastal area in north-west Sicily (Italy), was performed. At first, an investigation of the structure and seasonal dynamics of the population within this basin was performed. Thereafter, an analysis of the isotopic niche and trophic position was conducted comparing C. sapidus with two autochthonous brachyurans, Carcinus aestuarii and Eriphia verrucosa in order to clarify the trophic role of the blue crab and potential interaction with other crabs. Results showed that in this marine coastal area the blue crab is much abundant in the northern part of the basin during summer, and males and females are not uniformly distributed. Moreover, no relationship among abundance of the species, and abiotic (salinity and temperature) and biotic (macrophyte biomass) factors investigated was found. The study revealed that, even if is not as abundant as in other Mediterranean area, this species is largely capable of establish and reproduce even in a habitat where environmental characteristics (e.g., salinity and temperature) are remarkably different from those it experiences in its native environment as well in other areas to date invaded. Furthermore, the results of the analysis performed on the isotopic niche and trophic position of the three brachyurans species suggest that they exploit different food sources and have considerably diverse trophic habits. Specifically, the different position of the niches in the isotopic space, the negligible overlap and the relatively different trophic positions of the three species, suggest a repartition of the niche. Moreover, a mixing model performed to elucidate which sources are the most consumed by C. sapidus, highlighted a general preference for animal prey, although characterized by a considerable spatial and seasonal variation likely influenced by the temporal and local availability of animal and vegetal trophic resources. Eventually, an assessment of Callinectes sapidus as a biomonitor species was carried out, through the evaluation of metal concentration in blue crabs sampled in five locations across the Mediterranean Sea. Subsequently, a comparison with bivalves, the most used marine organisms for biomonitoring purposes, was performed to check whether the blue crab is able to provide reliable information on metal contamination in the environment. Results indicated that its omnivorous trophic habits may represent an important factor affecting trace metal content and, ultimately, its ability to provide information consistent with those that can be obtained from bivalves. The results emphasized that the trophic plasticity of blue crab and other invertebrate taxa proposed for biomonitoring purposes may represent an open issue in environmental toxicology. Accordingly, an advanced analysis of trophic habits through stable isotope technique may help to understand the observed patterns of variation in contaminant levels. Overall, the findings of the present thesis provided an advanced perspective on the invasion biology and ecology of Callinectes sapidus, in particular addressing previously unexplored knowledge voids regarding the variation and expansion of the species, its population structure and dynamics as well its trophic role in a recently invaded marine coastal area, and the potential use of the blue crab as a bioindicator. These results are an additional step towards a deeper knowledge of this invasive species, an essential aspect in the implementation of successful management strategies for the control and mitigation of its impact on Mediterranean Sea ecosystems

An updated dataset of published carbon and nitrogen trophic enrichment factors (Δ13C and Δ15N) for aquatic crustacean taxa

Stable isotopes of nitrogen and carbon (δ15N and δ13C) represent an important tool in food web ecology, useful for the determination of consumers’ diet and trophic position. One of the key requirements for an appropriate and reliable use of this methodology is represented by the application of species-specific trophic enrichment factors (TEFs, also defined as diet-tissue discrimination factors, DTDFs). Here we present an updated synthesis of carbon and nitrogen TEFs for aquatic crustaceans collated from literature sources. Specifically, on September 20th, 2022 the online databases ISI Web of Science and Scopus were searched for publications by a multiple search criterion using the terms “trophic enrichment factor” or “discrimination factor” in conjunction with “stable isotopes” and “crustacean”. The results were complemented with those obtained from queries on Google Scholar (https://scholar.google.com/) using identical keywords and subsequently saved using the freeware Harzings’s Publish or Perish ver. 7.27.284953. The literature search resulted in a total of 564 entries; subsequently, their titles and abstracts were screened in order to remove field investigations and laboratory studies not performed on aquatic crustacean species or estimating TEFs values on blood. The full text of the remaining 87 sources was examined in detail to select those where TEFs or DTDFs were reported explicitly at least for nitrogen, together with information on the taxonomy of the consumer and dietary resource, the consumer life stage, the analysed tissues, lipid extraction treatment, duration and temperature at which the experiment was performed. 23 eligible literature sources matching the aforementioned criteria were eventually selected, published between 1978 and 2019. The dataset is contained in Table 1; it includes, together with TEFs values, the literature source, the consumer and prey species scientific or common names, information on the environment (M = marine, F = Freshwater), information on the species life stage, the analysed tissue, the treatment used for lipids extraction (N = no treatment; Y = chemical extraction or mathematical normalization), the duration (in days) and temperature at which the experiment was performed (in °C), and the type and the isotopic values of the diet (δ13C and δ15N). complementary information regarding the the literature sources used to extract the data including permanent identifiers (bibliographic Citation DOI) if available are reported in Table 2

A global dataset of carbon and nitrogen isotopic signatures of the bluefish Pomatomus saltatrix and its potential fish prey

The bluefish Pomatomus saltatrix is a pelagic predator occurring in temperate and subtropical waters worldwide; in the Mediterranean Sea it was originally distributed in the southern and eastern sectors of the basin, yet in the last decade it has greatly extended its range towards the northward and westward sectors of the Mediterranean basin. Range-shifting marine species such as the bluefish have the potential to determine novel species interactions altering community structure and ecosystem processes analogously to what observed for non-indigenous species, thus acting as “native invaders”. It is to date acknowledged that the functional traits of non-indigenous species (NIS hereafter) may provide key information for predicting their impact within invaded habitats. Successful biological invasions are often facilitated for generalist species that can shift and adapt their trophic role in invaded food webs, ultimately affecting their structure and functioning. In this context, the analysis of carbon and nitrogen stable isotopes can provide important clues on NIS (and native invaders) functional impacts, as they can be used to investigate NIS trophic habits and, in turn, to detect post-invasion changes in food web structure. Here we provide a harmonized global compilation of 30 geo-referenced records of Pomatomus saltatrix δ13C and δ15N values taken from the published literature. To this end, on September 16th 2021 the online databases ISI Web of Science and Scopus were searched for publications by a multiple search criterion using the term “Potamotus saltatrix” in conjunction with “stable isotopes”. The results were complemented with those obtained from queries on Google Scholar (https://scholar.google.com/) and saved using the freeware Harzings’s Publish or Perish ver. 7.27.284953, using identical keywords. The literature search resulted in a total of 522 sources; subsequently, their titles and abstracts were screened in order to remove laboratory studies and field investigations not directly performed in marine environments. The full text of the remaining 247 studies was examined in detail to filter those where P. saltatrix occurrence was reported explicitly, together with information on the country, latitude and longitude, the year of the record, and at least the mean δ15N values of sampled specimens. Publications where the sampling location had no exact coordinates but was reported in maps were also included in the selection. In addition, the sources to be selected had to include isotopic information on potential fish prey of the bluefish, with the ultimate aim of providing the isotopic baseline for the estimation of the trophic position of the predator. To this end, the prey genera listed by FishBase (www.fishbase.org) for Pomatomus saltatrix were used as a reference. In addition, the trophic position of prey species was drawn from FishBase. 30 eligible publications matching the aforementioned criteria were eventually selected. Mean δ15N values were extracted from tables and figures together with mean δ13C values, δ15N and δ13C standard deviations and sample numerosity when available; figures were digitized after a fivefold enlargement and converted to numerical form using a graph capture software (https://automeris.io/WebPlotDigitizer/). Information on the country, location, season of the study, size of P. saltatrix specimens and its potential prey species were also extracted when available. For those studies where sampling locations had no coordinates but were reported in maps, all contextual information was used to locate the geographic area of the study in Google Earth. Maps were extracted using the freeware GIMP (ver. 2.10.20, https://www.gimp.org/), overlaid to the study area in Google Earth, and adjusted to match the background. Subsequently, the sampling area was georeferenced using placemarks; the coordinates of the sampling area was used to estimate the latitude and longitude in decimal degrees of its centroid using the centroid function from geosphere R package (https://cran.rproject.org/web/packages/geosphere/index.html). The dataset is contained in Table 1; complementary information regarding the description of the fields included in the dataset and of the literature sources used to extract the data including permanent identifiers (bibliographic Citation DOI) if available are reported in Table 2 and 3, respectively