Trollhättan-Öresjö Fiskevårdsområdesförening manages the fisheries in Öresjö and the two smaller lakes Stuvvikesjön and Gropsjön at the southwestern tip of Öresjö. The association has approximately 105 members.

The association has previously carried out several stocking of char, but no reproduction has been observed. More recently, the association's activities have mainly focused on protecting and developing the lake's crayfish population. A management area for crayfish was established in 2012 and in 2015 the County Administrative Board decided that Öresjö should be a protected area for crayfish. Unfortunately, the lake was affected by crayfish plague in the autumn of 2021. The association plans to restock crayfish when the lake is declared plague-free.

The association's members and guests are allowed to fish with hand gear throughout the lake upon presentation of their assigned fishing license or guest card. Within their own area, members may fish with nets and fish for crayfish according to the rules established at the fishing meeting.