Stone moroko (Pseudorasbora parva) is considered to be one of the most invasive fishes, dispersing rapidly all over Europe and also in the freshwaters of the Baltic Sea basin. A recent survey carried out in the catchment of the lower part of the Odra River (Poland) in 2015 and 2016 revealed a large new population of stone moroko, which had colonized the creek Wardynka. The sample of 518 fish caught was dominated by age groups 1+ (341 specimens) and 2+ (99 specimens); however, older fish were also present, which means that at the moment of analysis the species had been in the Wardynka for at least 5 years. |