Atlas des poissons de Wallonie : distribution, écologie, éthologie, pêche, conservation

The present report is a synthesis of a fifteen years investigation on the freshwater fishes of Wallony. The fourty one indigenous species recorded (see table 3) can be classified as follows with regards to the status of their population :

- 7 anadromous migratory species (Petromyzon marinus, Lampetra fluviatilis, Acipenser sturio, Alosa fallax, Alosa alosa, Coregonus oxyrhyncus, Salmo salar) are extincted.

- 4 species were recorded in small numbers (Plactychtis flesus, See trout, Lota lota and Leuciscus idus) and are virtually extincted as reproductive populations.

- Misgurnus fossilis, Cobitis taenia, Leucaspius delineatus and Rhodeus sericeus are rare, very locally distributed and highly endangered species for which severe conservation measures are urgently needed (legal protection, prohibition of fishing, natural reserves, protection of the biotopes).

- All the lithophilous species (Alburnoides bipunctatus, Barbus barbus, Chondrostoma nasus, Phoxinus phoxinus, Leuciscus cephalus, Leuciscus leuciscus, Thymallus thymallus, Salmo trutta fario, Cottus gobio and Lampetra planeri) are suffering a strong decline of their populations, especially in the heavy polluted Scheld basin and in several area of the more preserved river Meuse basin as well. The conservation of these species could be archieved by limiting the incidence of water pollution, eutrophication process and physical alteration of the habitats, improving some fishing regulations (legal size, closed seasons), developing methods of artificial reproduction and propagation, establishing integral reserves in any aquatic biotope with a relict or highly ecological representative population or fish community.

- Most other species have locally desappeared or declined due to chronic acute pollution but on the whole they are still wisdespread all over the country and even rather common in their particular habitats; they do not require any special conservation measures, except those relating to i) the maintenance of a sufficient water quality and habitat convenience for reproduction and to ii) an improvement of the fishery management, especially regarding the efficiency of restocking.