R. W. Gould W. T. Yasutake Gary Wedemeyer 1983 <p>The sensitivity of the leucocrit as a stress tolerance and fish health assessment method was evaluated by subjecting juvenile coho salmon, <i>Oncorhynchus kisutch</i>, or steelhead trout, <i>Salmo gairdneri</i>, to standardized crowding, handling, temperature and disease challenges. The leucocrit was a sensitive indicator of the physiological stress resulting from crowding at population densities of 0·2–0·4 kg l⁻¹, and to the stress of handling and to temperature changes. It was relatively insensitive to physiological sampling procedures which supports its continued development as a stress assessment method.</p><p>In the case of fish diseases, subclinical or active <i>Renibacterium salmoninarum</i> and <i>Yersinia ruckeri</i>infections had essentially no effect on leucocrit values. In contrast, active <i>Aeromonas salmonicida</i>infections significantly depressed the leucocrit. However, no change was seen during the subclinical (incubation) phase prior to the development of an epizootic. Thus, the potential of the leucocrit as a fish health assessment method appears limited.</p> application/pdf 10.1111/j.1095-8649.1983.tb02948.x en Academic Press Some potentials and limits of the leucocrit test as a fish health assessment method article