The Ponto-Caspian and native amphipod life history in the Daugava River, Latvia

Population structure, reproductive parameters and other life history traits are among the main preconditions for alien amphipods’ successful invasion. In freshwaters of Northern Europe, i.e. Latvia, overall Ponto-Caspian amphipods is little known. Furthermore, population structure reproductivity native Gammarus pulex have not been studied in Latvian freshwaters. The aim study was to describe varsoviensis, Pontogammarus robustoides coexistent G. pulex. Their period fecundity Daugava River were evaluated as part this from 2017 2019. results revealed that varsoviensis P. lasted four five months, with up three generations per year a high proportion juveniles. average number eggs 31 (maximum: 69) 28 81), ovigerous females both species being an 11.3 mm. had one generation brood 27 41) size 10.7