Development of cannibalism in larval northern pike, Esox lucius (Esocidae)

The development of cannibalism of northern pike (Esox lucius) larvae was st udied under controlled conditions. Pike larvae were reared in six glass, 50 -1 aquaria at three stocking densities: 440, 2 200 and 4 400 larvae per aqu arium. Fish were fed ad libitum with Artemia nauplii and sieved zooplankton . After 4, 8 or 12 days of rearing, pike larvae were anaesthetised and meas ured for total length (TL) and body weight (BW). Lowest survival and fish s ize were noted at the highest stocking density. The frequency of all cannib alistic attacks decreased in the order: highest > middle > lowest density; the frequency of successful attacks (expressed as the number of injured sib ling fish) decreased, however, in opposite order.