Changes in the distribution of amphipods in the Daugava River, Latvia

Abstract

Scientific information on amphipods and other peracaridan crustaceans in Latvian inland waters is insufficient. Therefore investigations of these animals are indispensable, especially because of the ongoing biological invasions of Ponto-Caspian amphipods causing changes in macroinvertebrate assemblages. Our recent investigation revealed that the alien amphipod Gammarus varsoviensis dominates amphipods in the upper courses of the Daugava River, whereas the other alien amphipod Pontogammarus robustoides prevails in the lower reaches of the river. Both these Ponto-Caspian amphipods were found co-occurring with the indigenous Gammarus pulex in the middle course of the Daugava River upstream from the Pļaviņas Reservoir. We predict that in the future the indigenous G. pulex will be fully exterminated by alien amphipods in the Latvian part of the Daugava River.

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

“…The occurrence of the three species -G. varsoviensis, P. robustoides and G. pulex -in the middle flow of the Daugava River differed from 2017 to 2019. It was rare for all three species to be found in one place together in the Daugava (Paidere et al 2019). Gammarus varsoviensis were observed at Daugavpils and Jēkabpils in all years of the study, and at Veczeļki in 2017.…”

“…Although G. pulex occurs in Latvian freshwaters, its distribution, population structure and life history traits are unknown. According to our previous investigations, G. pulex occurs in the Daugava River, mainly in its middle flow, together with the alien species G. varsoviensis and P. robustoides (Paidere et al 2019).…”

“…The species occurs in both the seaside lakes (Lake Liepāja and Lake Ķīšezers) and the estuaries of the large (Daugava, Lielupe and Gauja) and small rivers (Salaca, Saka and Venta) flowing into the Baltic Sea (Grudule et al 2007). According to our recent investigations in the Daugava River, the species occurs in the Lower Daugava River, mainly in the Daugava River reservoirs (Riga, Ķegums and Pļaviņas) (Paidere et al 2019;Paidere et al 2016). The species was intentionally introduced into Latvian waters -those nearest to Riga, Lake Lielais Baltezers and the Lower Daugava River (Ķegums Reservoir)in the 1960s as a valuable fish food (Bodniece 1976;Kachalova, Lagzdin 1968).…”

Common Freshwater Fish Nematodes in Latvia

“…Macrocyclops is one of the most common genera from Eucyclopinae in Latvian freshwaters (Deimantoviča et al 2011). Macrocyclops albidus is widespread in Latvian freshwaters (Dimante-Deimantoviča 2012), it can be recorded from a variety of water bodies such as lakes, rivers, ponds (Nagļi fish ponds) (Paidere 2019), floodplain lakes (floodplain Lake Dvietes) (Paidere 2013). Skrjabin, 1923 In Slokas Lake 20.0% of roach was infected.…”

Latvijas ūdeņu vides pētījumi un aizsardzība : Latvijas Universitātes 79. starptautiskā zinātniskā konference, Bioloģijas sekcija : referātu tēžu krājums

“…Ponto-Kaspijas sānpeldvēži P.robustoides un G.varsoviensis ir dominējošie sānpeldvēži Daugavā. Daugavas lejtecē un tās ūdenskrātuvēs ir izplatīts P.robustoides, bet vidustecē, augštecē G.varsoviensis(Paidere et al, 2016, Paidere et al, 2019.Tāpat kā iepriekšējo pētījumu laikā, arī 2020. gadā kvalitatīvi sānpeldvēžu paraugi tika ievākti vienu reizi mēnesī (izņemot jūniju, kad novēro juvenilo īpatņu uzplaukumu, paraugi tika ievākti divas reizes mēnesī) no aprīļa līdz septembrim Daugavā (vietās -Daugavpils, Jēkabpils, Veczeļķi un Gostiņi: Pļaviņu ūdenskrātuve). Paraugi tika ievākti piekrastes seklūdens daļā (~0,5 m dziļumā) ar rokas tīklu (25x25 cm, 500 µm).…”