Incidences de la pollution organique et de l'eutrophisation sur la faune ichtyologique de la Semois

Abstract

Fish surveys by electrofishing in the Semois (a tributary of the river Meuse) in 1977 showed the effects of a marked organic pollution (upper reaches of the Semois) and a serious eutrophication (lower reaches) on the fish fauna in the barbel-zone of the river. There was:- elimination or reduction of populations of C. gobio, S. trutta, A. bipunctatus, B. barbus, C. nasus;- replacement of B. barbus by L. cephalus;- reduction of the relative biomass of the group, B. barbus + C. nasus, which is a good indicator of the structural stability of the fish-coenosis;- reduction of the total biomass of fish.These results illustrate certain aspects of differences in pollution sensitivity (of an ecophysiological nature) and resilience (of a demographic nature) between fish species that are typical of this type of river. © 1980 Masson.