## 3 Results
### Epibenthic Communities  
In the central part of the Menorca Channel, higher abundance of ascidians was found in Non-impacted (235 \(\pm\) 44 individuals/1000 m\({}^{2}\)) compared to Low effort history area (119 \(\pm\) 19 individuals/1000 m\({}^{2}\); Figure 4). Higher abundance of sponges was also found in Non-impacted than in Low effort history areas: 101 \(\pm\) 26 vs. 41 \(\pm\) 12 individuals/1000 m\({}^{2}\) (Figure 4). Rhodoliths biomass in Non-impacted area (210.7 \(\pm\) 66.5 kg/1000 m\({}^{2}\)) was higher than in Low effort history area (64.2 \(\pm\) 20.8 kg/1000 m\({}^{2}\); Figure 5). All the diversity indices estimated showed higher values in Non-impacted than in Low effort history area (Figure 6): \(N_{90}\) (36.3 \(\pm\) 0.44 vs. 19.1 \(\pm\) 0.3 species), S (63.2 \(\pm\) 1.8 vs. 51 \(\pm\) 4.6 species), \(H^{\prime}\) (3.52 \(\pm\) 0.05 vs. 2.73 \(\pm\) 0.19) and \(J^{\prime}\) (0.85 \(\pm\) 0.01 vs. 0.69 \(\pm\) 0.04). In the southern part of the Menorca Channel, higher abundance of ascidians was found in Medium effort history (311 \(\pm\) 64 individuals/1000 m\({}^{2}\)) compared to High effort area (111 \(\pm\) 18 individuals/1000 m\({}^{2}\); Figure 4). Higher values of brown algae biomass were also found in Medium effort history than in High effort area (2.9 \(\pm\) 1.5 vs. 1.2 \(\pm\) 0.6 kg/1000 m\({}^{2}\); Figure 5). \(N_{90}\) was the only diversity index that showed significant differences between Medium effort history and High effort areas with higher values in Medium effort history area (30.3 \(\pm\) 0.44 vs. 27.6 \(\pm\) 0.3 species; Figure 6). Figure 3: Results of the composed Multidimensional Scaling (MDS) showing the ordination of beam trawl samples according to environmental variables analyzed (depth, slope, and backscatter of the seabed and horizontal (u) and vertical (v) components of bottom currents). Samples from Non-impacted, Low effort history, Medium effort history, and High effort areas are in green, yellow, orange, and red, respectively. Figure 4: Mean values and standard errors of abundance (individuals/1000 m\({}^{2}\)) for the main taxonomic groups, estimated from beam trawl samples in the four areas considered: Non-impacted (NI), Low effort history (L), Medium effort history (M), and High effort (H). \(p\)-values of the Student’s \(t\)-test to test for differences between areas are presented: \({}^{*}p<0.05\); \({}^{**}p<0.01\); \({}^{***}p<0.001\). Figure 5: Mean values and standard errors of biomass (kg/1000 m\({}^{2}\)) for the main groups of algae, estimated from beam trawl samples in the four areas considered: Non-impacted (NI), Low effort history (L), Medium effort history (M), and High effort (H). Red algae are Rhodophytes not included in rhodoliths. \(p\)-values of the Student’s \(t\)-test to test for differences between areas are presented: \({}^{*}p<0.05\); \({}^{**}p<0.01\); \({}^{***}p<0.001\). In the central part of the Menorca Channel, SIMPER table showed that main species contributing to similarity in the Non-impacted area were the crustaceans _Inachus dorsetensis, Pagurus prideaux_, and _Anapapavirus laevis_, the fish _Buenia massutti_, and the ascidian _Ascidia mentalua_ (Table 2). In Low effort history area, these species were the same, with the only exception of the echinoderm _Ophiura ophiura_ instead of _A. mentalua_. This species, jointly with the other ascidian _Aplidium northmanni_ and the echinoderm _Echinaster sepositus_ showed higher abundances in Non-impacted compared to Low effort history area. The sponges _Mycale_ (_Aeggropila_) _contarenuti_, Calcarea sp. and _Siphonochalina_ sp., as well as the ascidians _Diazona violacea_ and _Polycarpa nnamillaris_, just contribute to similarity in Non-impacted area. Figure 6: Mean values and standard errors of \(N_{90}\). Species Richness (\(S\)), Shannon (\(H^{\prime}\)), and Pielou’s evenness (\(I^{\prime}\)) diversity indices, estimated from beam trawl samples in the four areas considered: Non-impacted (NI), Low effort history (L), Medium effort history (M), and High effort (H).