Undens Fiskerättsförening was formed in the mid-1950s. This association was formed to act as an active counterpart to Sweden's first commercial nuclear power plant, which was never located in Unden.

To get help with liming measures when the pH value in the lake approached 5.0, Undens Fiskevårdsområdesförening was formed. Since 1977, Undens FVOF has received government grants for liming measures.

Crushed limestone has been transported to the char spawning grounds. Unden's tributaries are limed annually by boat and helicopter. Water samples are taken 4 times a year at 5 predetermined locations to be able to monitor the water quality over time. The water's pH value is now good and is kept at the right level with the help of liming. Fishing regulations have been introduced to ensure that sustainable fishing can be maintained.