The English Channel comprised the ICES areras VIIe and VIId which are more or less a part of the North Sea area as delimitated by Ascobans. Two studies (Pingiroise and FilManCet) were conduced in that area. Filmancet study comprises two different areas: North Brittany and Nord Pas de Calais (Figure 1). The main objectives are to quantify accidental catches of marine mammals in set nets and identify solutions to limit them. Pingiroise is a study dedicated to the set net fishery in the Iroise area at the west of Brittany. The three objectives of that study in a marine protected area was to make comparative trials with pingers, to determine the bycatch in set net fishery operating inside and around the Marine protected area and to estimate the abundance and the distribution of cetaceans. Harbour porpoises, pilot whales and common dolphin are sometimes incidentally caught in set nets; The by-catch rate for harbour porpoise is very low compared to other areas (Celtic Seas or North sea). The low bycatch rate calculated in the fisheries in Brittany is probably due to a lower abundance of the harbour porpoise in the sampled area: 0.132 ind/km2 in Iroise Sea (Pingiroise study) compared to 0.408 ind/km2 in the Celtic Sea (SCANSII). An other explanation could be linked to the fishing process, especially for spider crab netting. The pinger systems as mandated by the EC 812/2004 regulation are very expensive, not always reliable and their utilization involved fishermen security concerns. The less expensive system seems the DDD02 placed at each end of the net but the system has the greatest exclusion area. These experiments raise the problems of practicability and certification of acoustic deterrent systems as some trades have a poor technical reliability. Furthermore, first results of the FilManCet study show that it is necessary to assess the impacts of fishing gear with an area and seasonal approach in order to find the more adapted solution to limit them.