Morphological characteristics of local populations of European vendace Coregonus albula (L.) in some lakes of Latvia during 50 years

The vendace (Coregonus albula (L.)) is a widespread fish in the waters of the Holarctic and has been much studied in regard to history of spread and evolution. Statistical analysis of morphometric and meristic changes in Coregonus albula in some Latvian lakes for the last 50 years was conducted. Cluster analysis of meristic parameters showed that the vendace populations of lakes Stirnu - Alūksnes have become closer in meristic properties while the vendace populations of lakes Drīdzis - Sventes have become more dissimilar. The diversity and variation of morphological characteristics of vendace in the studied lakes are within the range of variations of the European vendace (Coregonus albula), although due to its flexibility it makes a lake-specific form depending on the local conditions of each reservoir. The discovered differences in the vendace populations from Lakes Nirzas, Rāznas, Stirnu, Alūksnes, Drīdzis, and Sventes seem to have resulted solely from/due to the adaptation of vendace to living conditions, which has changed during the previous 50 years.