Fig 1.
Geographic distribution of the Operational Geographical Units (OGUs) considered in this study.
Green dots are the centroids of each OGU and the names of the countries designate the OGUs names.
Table 1.
Countries and Geographical Sub-Areas (GSAs) corresponding to each Operational Geographical Unit (OGUs).
Table 2.
Chondrichthyes species recorded in the Mediterranean Sea, their occurrence at each Operational Geographical Units (OGUs) and IUCN status in a regional assessment.
Key: ~ Lessepsian invasive species; § Vagrant and visitors; * Highly migratory species; & it presence is doubtful. CR, Critically Endangered; EN, Endangered; VU, Vulnerable; NT, Near Threatened; LC, Least Concern; NA, Not Assessed; DD, Data Deficient [25].
Table 3.
Independent variables used in this study for each Operational Geographical Unit (OGU).
Key: LAT, latitude (degrees); LON, longitude (degrees); OAR, the OGU area (km2); DISTG, distance from the centroid of each OGU to the Strait of Gibraltar (km); DISTS, distance from the centroid of each OGU to the Suez Canal(km); SST, sea surface temperature (°C); SD, salinity in depth (PSU); FAM, number of taxonomic families of bony fishes for each OGU.
Table 4.
Pearson correlation coefficient between the independent variables used in this study for each Operational Geographical Unit (OGU), and dependent variables: Chondrichthyes species Richness (CSR), Chondrichthyes species Richness without Lessepsian invasive species (LCSR); Chondrichthyes species Richness without vagrant and visitors (VCSR); Chondrichthyes species Richness without highly migratory species (HCSR); Chondrichthyes species Richness without Lessepsian invasive species, highly migratory species, vagrant and visitors together (ALLCSR).
Pearson correlation coefficient is shown (significance in brackets). Key: LAT, latitude (degrees); LON, longitude (degrees); OAR, the OGU area (km2); DISTG, distance from the centroid of each OGU to the Strait of Gibraltar (km); DISTS, distance from the centroid of each OGU to the Suez Canal (km); SST, sea surface temperature (°C); SD, salinity in depth (PSU); FAM, number of taxonomic families of bony fishes per OGU. ** Significant correlation.
Table 5.
Results of the multiple lineal regression models among Chondrichthyes Species Richness (CSR) excluding only Lessepsian (LCSR), only vagrant, visitors (VCSR), and only highly migratory species of Chondrichthyes previously mentioned (HCSR), and excluding all of them pooled together (ALLCSR) versus historical, ecological and environmental factors.
Key: DISTG, distance from the centroid of each OGU to the Strait of Gibraltar (km); OAR, the OGU area (km2).