Size- and density-dependent habitat use in predators: consequences for habitat shifts in young fish
Article first published online: 10 FEB 2003
Journal of Animal Ecology
Volume 72, Issue 1, pages 156–168, January 2003
How to Cite
Byström, P., Persson, L., Wahlström, E. and Westman, E. (2003), Size- and density-dependent habitat use in predators: consequences for habitat shifts in young fish. Journal of Animal Ecology, 72: 156–168. doi: 10.1046/j.1365-2656.2003.00681.x
- Issue published online: 10 FEB 2003
- Article first published online: 10 FEB 2003
- Received 2 April 2002; accepted 23 September 2002
- Perca fluviatilis;
- predator behaviour;
- prey habitat shifts;
- predation risk;
- predator size and habitat use;
- prey size
- 1When different size classes of predators use different habitats, the habitat-specific predation risk for prey may change as prey increase in size due to the size-dependency in predator–prey interactions.
- 2To study the effects of predation risk on habitat shifts in growing prey, we used a combination of whole-lake manipulations and field data, covering 5 years from three lakes on (1) body sizes at habitat shifts in young-of-the-year perch (YOY) perch (Perca fluviatilis) and (2) habitat use and densities of two size classes of cannibals (1 year old and ≥ 2 years old).
- 3YOY perch shifted habitat to the pelagic immediately after hatching and exhibited a second shift back to the littoral zone at a size range of 11–30 mm. Cannibalism from 1-year-old perch decreased over time, whereas cannibalism from perch ≥ 2 years old increased over time but did not include early larval stages. The habitat use of 1-year-old perch was restricted to the littoral habitat, whereas perch ≥ 2 years old used both the pelagic and the littoral habitats.
- 4Habitat shifts in YOY perch were unrelated to differences in resource levels between the two habitats as YOY perch were either yolk sac feeding (first habitat shift) or had similar foraging gains in both habitats (second habitat shift).
- 5The size when YOY perch shifted back to the littoral zone was related positively to the densities of 1-year-old perch, whereas no clear relationship was found between shift size and the density of perch 2 ≥ years old. The latter was suggested to be due to the higher density and the larger variation in densities of 1-year-old perch and that the predation risk from perch ≥ 2 years old was less habitat-specific.
- 6Our results suggest that size-dependent habitat use and size specific predation risk evoked by cannibals affect the size when YOY perch shift back to the littoral zone.