Mjøsa is known for its large-sized trout population, especially the fast-growing "hunderørret" (dog trout) which feeds on a fish diet and can weigh over 10 kg
. The best fishing method is trolling/dorging from a boat, particularly during the periods of May 1st–August 31st and October 1st–December 31st. The minimum size for catch is 50 cm.
Facts about trout in Mjøsa:
- "Hunderørret" (Dog Trout): One of Europe's largest trout strains that spawns in Gudbrandsdalslågen and grows large in Mjøsa.
-
Norwegian record: The largest trout caught with a rod in Norway, a "hunderørret" weighing
, was caught in Mjøsa in 1981.
- Fishing seasons: Rod fishing is allowed all year round, but trolling is limited to May 1st - August 31st and October 1st - December 31st.
- Regulations: All trout under 50 cm must be released. Max 4 lures per boat for trolling.
- Pollution: Historically, there have been warnings against eating much large trout from Mjøsa due to pollution, but fishing remains popular as a "catch and release" activity.
20 fish species have been registered in Mjøsa, and in addition to trout, there is good fishing for pike, perch, and whitefish.