## 3 Results  
In total, we captured six males of _C. sapiens_, one per site, with a carapace width ranging from 14.6 to 24.1 mm and a weight from 134 to 253 g (Table 2). All individuals were \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Region** & **Province** & **Site** & **Acronym** & **N** & **E** & \
\begin{tabular}{c} **Distance** \\ **from the Sea** \\ \end{tabular} &
\begin{tabular}{c} **Degree of Preservation** \\ **Theoretical Results** \\ \end{tabular} \\ \hline \multirow{3}{*}{Tuscany} & \multirow{3}{*}{Grosesto} & \multirow{3}{*}{Villa Clodia} & \multirow{3}{*}{VC} & \(42^{\circ}47^{\prime}03.91^{\prime\prime}\) & \(10^{\circ}56^{\prime}26.22^{\prime\prime}\) & \multirow{3}{*}{5.5 km} & Natural Reserve (Site of \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\ \hline \multirow{3}{*}{Latium} & \multirow{3}{*}{Latina} & \multirow{3}{*}{Lago di} & \multirow{3}{*}{LF} & \(41^{\circ}18^{\prime}45.66^{\prime\prime}\) & \(13^{\circ}21^{\prime}47.05^{\prime\prime}\) & \multirow{3}{*}{3.7 km} & Regional Natural Park (Site of \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\ \hline \multirow{2}{*}{Basilicata} & \multirow{2}{*}{Matera} & \multirow{2}{*}{Terzo Cavone} & \multirow{2}{*}{TC} & \(40^{\circ}17^{\prime}44.80^{\prime\prime}\) & \(16.43^{\circ}54.08^{\prime\prime}\) & \multirow{2}{*}{7.5 km} & Nature 2000 network \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Sites (from north to south) of the blue crab occurrence within the study area: distance from the sea is also reported. Figure 1: Locations of sampling sites and the blue crab occurrence in Italian freshwaters to date. observed in coastal inland waters showing a salinity within values of typical freshwaters (Table 3). In the case of the Spergolaia sampling station, many more samples could have been caught due to a consistent demographic density of the species distributed over a wide area. However, a numeric evaluation of the population was not assessed, since it was not a specific focus of the project. Environmental descriptors (Table 3) witnessed low salinity concentrations, with the latter being mostly referable to freshwater affected by saltwater encroachment. Despite measured values of 3.8% in station Villa Clodia and Spergolaia (salinity unknown), all sympatric fish species were strict freshwater taxa, such as carps, rudds, spanish barbels, chubs, channel catfish, bleaks, and crucian carps, together with diadromous eels, shads, mullets, sand smelts, Mediterranean tooth carps, and seabases; in other sites, such as Rio Claro and Lido di Scansano, the sampled blue crab specimens were observed in sympatry with freshwater mussels. Scientific names of freshwater species are reported in Table 3.  
The analysis performed on non-marine occurrences from [13] clearly confirmed the high euryhaline adaptability of _C. sapidus_ (Figure 2). In total, 1820 records were extracted; in both native (1761 records) and invaded ranges (59 records), the species was reported to occur in inland waters at distances >64 km from the coastline (>250 km in native areas). Noticeably, the distance data were calculated \"as the crow flies\" without considering the hydrographic network; thus, they necessarily provide a conservative estimation of the actual ability of the blue crab to colonize freshwater environments. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Region** & **Province** & **Site** & **Carapace Width (cm)** & **Weight (g)** \\ \hline \multirow{2}{*}{Tuscany} & \multirow{2}{*}{Grosseto} & VC & 15.0 & 160 \\  & & SP & 14.7 & 140 \\ \hline \multirow{2}{*}{Latium} & Latina & LF & 14.6 & 134 \\  & & RC & 21.4 & 208 \\ \hline \multirow{2}{*}{Basilicata} & \multirow{2}{*}{Matera} & TC & 24.1 & 253 \\  & & LS & 18.4 & 184 \\ \end{tabular}
\end{table} 
Table 2: Carapace width (cm) and weight (g) of the blue crab males observed in each sampled site (from northern to southern).