Low, Warm Water Prompts Fishing Restrictions; Portions Of Lower Madison And Upper Big Hole Affected
Consistent high water temperatures and low stream flows have prompted Montana Fish, Wildlife & Parks officials to close portions of two southwest Montana rivers to fishing beginning Monday, July 22 until conditions improve:
Closures will be from 2 pm to midnight daily beginning Monday, July 22 until conditions improve:
- Lower Madison River – from Ennis Dam (east of McAllister) to the Mouth
- Upper Big Hole River – from the headwaters (outside Jackson) to Dickey Bridge
In the area of concern, the water temperatures in the Lower Madison have exceeded 73 degrees for 18 of the past 22 days. Water temperatures in noted area of the Upper Big Hole River have exceeded 73 degrees for 3 consecutive days.
FWP’s drought plan calls for angling restrictions to be imposed when maximum daily water temperatures equal or exceed 73 degrees for 3 consecutive days. The preferred water temperature for rainbow and brown trout is about 55-57 degrees. Brown trout, rainbow trout and mountain whitefish caught when water temperatures exceed 73 degrees exhibit an increased mortality rate (4% to 28%) due to the cumulative stress.
Anglers should also be aware that the Jefferson River may soon require similar restrictions. Current flows and temperatures are close to trigger thresholds identified in the Jefferson Watershed Councils Drought Management Plan developed in conjunction with FWP.