Orleans, IA (KICD) — Sixty percent of the Muskies at the Spirit Lake fish hatchery died last year, and 25 percent of the spawn had deformities. Hatcheries Biologist Kim Hawkins says they’ve determined the nitrogen level in Big Spirit Lake has been naturally increasing over the past decade.

Last week the Iowa Natural Resources Commission approved an update to the facility in Orleans.

Hawkins says the hatchery will now use city water instead of lake water, which should make other destinations confident water that muscles won’t get transported to their lakes from Dickinson County.

Only the muskie produced at the Spirit Lake Fish Hatchery have been affected, but they’re held longer than other species.