Historical fish survey datasets from productive aquatic ecosystems in Lithuania

Here we present a newly digitized fish monitoring dataset for two major Lithuanian inland ecosystems – Curonian Lagoon and Kaunas Water reservoir. The data comprises fish surveys conducted during 1950s to 1980s, using a range of fishing gears and sampling methods. Three different definitions or methods describe the level of detail for each fish community study: Method 1 surveys include individual fish sizes and weights, Method 2 surveys record frequencies of fish in length or weight groups, whereas Method 3 only records the total catch biomass of a given species.