Observations of behavioural responses of fish to environmental stress in situ.

Recovery processes operating within a stressed ecosystem are dependent in part on natural avoidance behaviour or acclimatization of organisms to otherwise unfavourable conditions. Adaptation to an altered environment can be achieved through either genetic or non-genetic means. Five case histories are presented using Cyprinus carpio, Carpiodes cyprinus, Ictalurus punctatus, Salvelinus fontinalis, Semotilus atromaculatus, Catostomus commersoni, Lepomis cyanellus and L. gibbosus, which illustrate in situ behaviour of fishes to stress conditions, viz. thermal and organic pollution. -from Authors