The ecology of the zander, Stizostedion lucioperca L.

Abstract

The study of the ecology of the zander (Sitzostedion luciperca L.) followed three lines of investigation, a literature review, field studies and laboratory studies. Information on the taxonomy, behaviour, physiology, reproduction, distribution and ecological impact was reviewed. Field studies investigated the selectivity of the methods used to obtain zander fom Fenland and Midland zander habitats during the period 1978 to 1981. The growth characteristics of the major zander populations were validated. The feeding habits of the zander were determined from species, size and number of prey eaten: comparisons made with the available prey fish populations indicated that zander showed a preference for relatively small prey fish, but did not show any specific selection of particular species of prey. The maximum size of prey eaten was noted and the significance of the zander's method of swallowing prey considered. Marking provided information on the zander's movement and home range: movements were sometimes rapid and over considerable distances, but home ranges were considered to exist. Data from marking provided evidence of a change of zander population number and biomass in the Great Ouse Relief Channel from 1978 to 1980. Length-weight relationships and a study of the visceral fat content, showed that there existed considerable variations in condition between populations. Sexual development and reproduction was studied and related to other percids. Laboratory studies investigated the feeding behaviour of the zander. The rate of digestion of prey fish was determined and hypothetical examples used to confirm existing observations of zander food requirements.