Öresjö Fiskevårdsområdesförening manages fisheries in Öresjö and the two smaller lakes Stuvvikesjön and Pit Lake at Öresjös southwestern tip. The association has about 105 members.
Öresjö, located in the municipalities of Trollhättan and Lilla Edet Vanersborg, is a 1093 ha (about 11km²) large oligotrophic lake with a maximum depth of 33 meters. Although the lake is located in an acidification affected area is the water quality good, with a pH around 7.0. The lake is controlled by a difference of 1m between the dam and the reduction limit. Öresjö included in Bäveåns basin, which is a sanctuary for the water supply of Uddevalla (Köperödssjöarnas water protection).
Öresjö has a stable population of mainly perch and pike. The association has previously made several stocking of trout, but no reproduction has been observed. Recently, before operation of the association focused mainly on protecting and developing the lake's populations of crayfish. A management area for crayfish was formed in 2012 and 2015, the county administrative board decided to Öresjö will provide sanctuary for crayfish.