*3.3. Canyons*

The fishing targeting the deep-water shrimps in the northwestern Mediterranean is carried out on both the slope and the walls of the submarine canyons [11,14,67,120–124].

In the western Mediterranean, *C. conger* and *P. blennoides* are the fish species captured with the highest biomass at the head of the Blanes Canyon [124]. The juveniles of some deep-sea shrimps (e.g., *Plesionika heterocarpus, P. edwardsii, P. gigliolii*, and *P. martia*) and fish (such as *P. blennoides*, *Mora moro*, and *Lepidion lepidion*) are found to be distributed in the benthic intermediate nepheloid layers of the Blanes Canyon, which seems to act as a nursery area for these species [125,126]. From the canyons in the eastern part of the Gulf of Lions, blackmouth catshark and European hake are among the most abundant species [15]. Spawning females of angler and European hake have been more commonly observed within the submarine canyons of Petit-Rhône and Grand-Rhône than on the adjacent open slope [15]. *G. melastomus*, *H. dactylopterus*, and *P. blennoides* are the most frequently observed fish species in French Mediterranean submarine canyons characterised by the presence of CWC species [17]. Discarded fishing gear, including entangled nets and lines, has been observed in the canyons of the western Mediterranean where CWC species thrive [17,127–129].

The shark *G. melastomus* and the teleost fish *H. dactylopterus* and *P. blennoides* are the most frequently captured species in the Quirra Canyon (Sardinian waters), where valuable species—such as the European hake and the deep-water red shrimps—are also collected [130].

Eastward, in the Bari Canyon where CWC species thrive, the blackmouth catshark and the teleost fish European conger, blackbelly rosefish, European hake, blackspot seabream, and greater forkbeard have been found to be more abundant in the canyon than in the adjacent area [71,81]. In particular, greater forkbeard showed significantly greater abundance and biomass in the canyon than outside. Blackspot seabream are exclusively caught inside the canyon. A greater number of both smaller and larger individuals of European conger and greater forkbeard are found in the Bari Canyon than on the open slope. Mature females and males are mostly observed in the canyon in all of the most abundant species, indicating the role of the Bari Canyon as a refuge area and an EFH for fish species exploited in the neighbouring fishing grounds [71,83]. Longline remains have been observed in this canyon, which has a complex bottom topography and is not accessible to trawling [97].

Indeed, canyons seem to benefit and support fisheries [14,71,83,131,132], providing spawning and nursery sites as well as refuges for several commercial species [15,17,69,79, 80,84,97,122,126,133].
