Figure 7
Biomass of three fish groups (herbivores: green, omnivores: blue, mesopredators: red) in gillnet catches (fish older than 0 + ; kg per 1,000 m2 of gillnets) of (A) Most, (B) Milada and (C) Medard. Pike was stocked in 2011–2013 (855 kg each year) and 2005 (237 kg) to Most and Milada, respectively. In Medard, pike occurred from the beginning (i.e. 2008). Beginning of grey part shows the first relevant presence of catfish in the lakes (2012 for Most and 2006 for Milada) and subsequently represents estimated biomass of catfish population (kg ha−1). Catfish were stocked in autumn of previous years (2011 for Most and 2005 for Milada), in all cases well after individual gillnet sampling campaigns. This is the reason why illustrations of catfish presence begin one year later, when gillnet catches reflect (for the first time) potential impact of catfish on populations of herbivorous, omnivorous and mesopredatory fishes. Biomass for years 2012–2014 in Most and 2006–2007 in Milada is based on cumulative amount of stocked fish. Biomass for year 2015 in Most and 2014–2015 in Milada is calculated from recaptures.
