Temporal stability in size distributions and growth rates of three Esox lucius L. populations. A result of cannibalism?

The population total length (LT) structures and individual growth trajectories for three stream living pike Esox lucius populations were studied for 7 years. All three populations exhibited small variation in both population LT structure and individual growth trajectories over time. These dynamics contrasted to the much more variable population LT structure of perch Perca fluviatilis studied previously. The difference in population dynamics between the two species was related to differences in prey:predator size ratios. The pike populations in the more open and larger streams grew to larger sizes, but this difference in life history did not affect population dynamics of pike. It is concluded that (1) cannibalistic population dynamics may be predicted from individual life-history characteristics such as minimum and maximum victim:cannibal size ratios and (2) the cannibal-driven population dynamics observed in pike seems to be robust to variation in environmental conditions (system openness). # 2006 The Authors