Food choice and development of juvenile pike in different habitats within a lake

Habitat choice can be considered as a trade-off between food availability and risk of predation. Ontogenetic differences in habitat choice can therefore be expected to be a result of changes in foraging ability and/or predation risk. 0+ pike are usually found close to vegetation, but in a lake many different types of vegetated habitats may exist with high variation in the amount of different food items (e.g. invertebrates and fish), habitat complexity and predation risk. In this experiment we studied the development of 0+ pike in two different vegetated habitats, i.e. emergent (Cladium mariscus) and submerged vegetation (Chara sp.) within a shallow lake. We found that 0+ pike in the dense Chara vegetation were favored during the early season, whereas pike in the less complex Cladium vegetation were favored in the late season. This could be linked to ontogenetic changes in food choice and differences in food availability between habitats and between sampling dates.