Habitat distribution and size structure in freshwater fish communities: effects of vendace on interactions between perch and roach

In a study of habitat selection and size structure in three fish species in 115 Swedish lakes, roach Rutilus rutilus used the pelagic habitat to a lesser extent and were lower in pelagic biomass in the presence of vendace Coregonus albula. Size distributions of roach were skewed toward larger sizes in lakes with vendace, although a similar pattern of size-dependent habitat use was found regardless of lake group. In disagreement with predictions, vendace did not affect relative perch Perca fluviatilis biomass, size structure, or the proportion of large perch. However, a higher growth for large perch indicated higher per capita energy intake in lakes with vendace.