Recovery Signals of Rhodoliths Beds since Bottom Trawling Ban in the SCI Menorca Channel (Western Mediterranean)  
[PERSON]  
1 Centre Oceanografic de les Balears, Instituto Espanol de Oceanografia (IEO-CSIC), 07015 Palma, Spain; 1 [EMAIL_ADDRESS] (C.I. ); [EMAIL_ADDRESS] (F.O. ); [EMAIL_ADDRESS] (G.J. ); 1 [EMAIL_ADDRESS] (S.M. ); [PERSON]RESS] (D.D. ); [PERSON]RESS] (J.A.D. ); [PERSON]SS] (S.J. ); 1 [PERSON]] (S.R.-A. ); [PERSON] (N.R.d.I.B. ); [PERSON]S] (E.M.)
2 College of Science and Technology, Unite de Formation des Sciences de la Terre et Environment, Universite de Bordeaux, 3300 Bordeaux, France 2  
[PERSON]  
1 Centre Oceanografic de les Balears, Instituto Espanol de Oceanografia (IEO-CSIC), 07015 Palma, Spain; 1 [EMAIL_ADDRESS] (N.M.-C.); [EMAIL_ADDRESS] (J.-T.V) 1 [EMAIL_ADDRESS] (J.-T.  
depth [3], as long as there is enough light input for their growth [4; 5; 6]. Rhodoliths prefer sedimentary bottoms subject to moderate water currents, allowing a rolling movement that eases their growth, prevents burial by sediment, and hinders overgrowth by other algae [7; 8; 9]. Rhodoliths-forming species are considered bioengineers [2; 10; 11; 12], as they increase the structural complexity of the sedimentary bottoms, creating habitats that provide the refuge needed for a wide variety of marine species during key vital stages such as settlement and nursing [12; 13; 14; 15; 16]. Moreover, rhodoliths beds are one of the main biogenic sources of calcium carbonate on the planet, with a potential role in climate regulation [17]. Even so, different impacts, such as rhodoliths extraction, fishing, aquaculture, pollution, invasive species, and the combined pressures of ocean warming and acidification, endanger this habitat and its important biological and physico-chemical role [2; 10; 16; 18; 19]. Fishing activities, attracted by the presence of valuable commercial species on these rhodoliths beds, cause a series of direct and indirect impacts on this habitat [10; 20; 21; 22]. The presence of those species focuses the fishery activity, and also results in a high proportion of rhodoliths extracted as discards, mostly by bottom trawl fishery [23; 24]. Bottom trawling is particularly harmful due to the direct extraction of rhodoliths causing direct physical damage, including breakage of thalli as well as abrasion and dispersion of rhodoliths [25]. Besides, sediment re-suspended by bottom trawling, once settled, can bury rhodoliths, causing high mortalities due to light being unable to reach the algae, plus photosynthetic activity is stopped at the same time that smothering with fine sediments may limit the gaseous exchange needed by the algae to survive [5]. The resulting reductions in biomass and diversity of rhodolith species, as well as the shift in the biological communities of rhodoliths beds, favor opportunistic species that do not require a stable environment to develop [10; 26]. The pronounced oligotrophy of the waters around the Balearic Islands (western Mediterranean), along with a dry climate, the reduced watershed areas, the karstic nature of most of the islands favoring rapid infiltration of rainfall, and the lack of river runoff, explains the high transparency of the waters in the area that enables algal populations to grow until 90-100 m depth [27; 28]. Red algae beds, with two main communities being rhodoliths and _Peysonnelia_ beds, dominate the coastal continental shelf landscape down to 85 m depth, overlapping with the traditional fishing grounds of the bottom trawl fleet [29; 30]. The Menorca Channel is an area approximately 36 km wide, located between Mallorca and Menorca islands, in the northeastern part of the Balearic Promontory, which corresponds to a northeast prolongation of the Betics (Figure 1) [31]. It represents almost 20% of the surface of the continental shelf around these islands. The seafloor has a smooth regular relief, until the continental shelf edge at 120-150 m, where it sharply deepens [31; 32].