Sustainable utilization of wetlands is determined by the perceptions/attitudes of fishermen who are the main users of the lake resources. Successful implementation of conservation policies, management measures and environmental education programmes requires consideration of those attitudes and resolution of the conflicts between humans and the natural environment. Lakes Vistonis, Kerkini and Mikri Prespa in Greece, although wetlands of international importance, suffer severe conservation problems with a continuous deterioration of their resources. The aims of this paper are: (1) to compare the conservation attitudes of commercial fishermen of those lakes; (2) to explain those differences through variations in the socio-demographic and fishing technology/practices characteristics, and (3) to suggest proper education and management measures in order to resolve inherent conflicts. The opinion/attitude survey, carried out with a sample of 110 commercial fishermen, revealed that those in lake Vistonis differ significantly in their attitudes and perceptions towards wetland ecosystems, birds and more specifically pelicans from fishermen in lakes Mikri Prespa and Kerkini. The former expressed the most negative attitude to the environment. The conflict identified was towards the fish-eating birds, particularly cormorants preying heavily on the fish ponds they have constructed. However, fishing practices of these same fishermen are positive towards the resource they harvest. This attitude may result from the form of organization they have adopted in a fishermen's co-operative where strict regulations towards sustainable utilization of fisheries are enforced. On the other hand, in lakes Kerkini and Prespa, fishermen are harvesting individually the maximum days permitted, using small mesh nets and illegal fishing methods, thus imposing intensive pressure on the fisheries. As a result, strong competition for fisheries prevails between them. An education/information programme should be designed and implemented in the three lakes aimed at highlighting the values of wetlands, of the various ecosystem elements and interrelationships. The programme should also emphasize the interdependence of economic and environmental interests. Proper management measures should be taken to abate fish-eating birds' depredations in Vistonis.