Effect of food quantity and quality on the reverse in competitive success between 0+ perch and roach

Project No. KJB600960810

Applicant: RNDr. Jiří Peterka, PhD.

Financial support: Grant Agency of the Academy of Sciences of the Czech Republic

Duration: 2008-2010

Young-of-the-year perch and roach dominate the 0+ fish communities of meso- to eutrophic temperate water bodies across Europe. General succession from dominance of perch to roach with increasing ecosystem productivity has been documented for lakes of different trophic status and when comparing fish community structure within reservoirs with pronounced longitudinal gradients. Better competitive abilities of juvenile roach for crustaceoplankton have been suggested as responsible for these changes. But recently, the higher efficiency of roach for copepod or cladoceran prey was doubted. This project aims to clarify the effect of intra- and interspecific foraging competition of juvenile roach on perch in manipulative enclosure experiments with larvae and juveniles of both species, and particularly, focuses on the effect of food quantity and quality (prey taxa, prey size, timing of diet shifts etc.) on the changes in competitive success (evaluated as realized growth) between both species.