A regular census of Cormorants (i.e. 4 -10 counts per month) was carried out on each fishpond. Fish stock data were provided by the local fishery company, Rybařství Kardašova Řečice Ltd.
Breeding Cormorants occur in the study area since 1983. The number of breeding pairs increased up to 1988 and later on fluctuated.
A recent increase in number of breeding pairs was recorded since 2002 up to 2005 when 217 pairs bred. The main breeding colony is located on the Ženich fishpond (49.01N, 14.51E), the other on the Krvavý fishpond (49.08N, 15.07E).