Montana Fish, Wildlife, and Parks is investigating vandalism at the Causeway Fishing Access Site near Helena.
FWP says that materials and labor to clean up the vandalism will cost at least $2,200.
FWP is asking anyone with information about the incident to call 1-800-TIPMONT. Callers are kept confidential and a reward is possible.
The fishing access site is located several miles northeast of Helena.
The FWP website says: "Causeway is a state fishing and public access site located in southwest Montana on Lake Helena. This is a day use area providing fishing access. There is a boat launch for non-motorized boats only. There are restrooms at the site with handicapped facilities provided and a handicapped fishing pier."