Natural Stream Flow Is Best For Trout

Natural Stream Flow Is Best For Trout
Natural Stream Flow Is Best For Trout

Natural stream flow suits native trout populations best, according to a new study that is the first to examine the impacts of dam operations on threatened freshwater trout. The study appears in River Research and Applications.

In a study to identify the potential impacts of Hungry Horse Dam (Montana) operations on declining native trout populations, scientists with the U.S. Geological Survey, Miller Ecological Consultants, Inc., Spatial Sciences & Imaging and Montana Fish Wildlife and Parks examined how changes in river flow affect fish habitat on the upper Flathead River in Montana.

Our research suggests past flow management practices created sporadic flow fluctuations that were likely detrimental to threatened bull trout and westslope cutthroat trout populations in the upper Columbia River Basin, said Clint Muhlfeld, project leader and USGS scientist. With Montana providing 40 percent of the U.S. water storage in the Columbia Basin Power and Flood Control system, water demands and biological impacts are significant.

Populations of native bull trout and westslope cutthroat trout have declined throughout ranges in western North America due to a many factors, including habitat destruction, fragmentation and non-native species. Dam operations in the Columbia River Basin have contributed to these declines by changing flow and habitat, and disrupting routes of fish migration.


Loss of habitat connectivity and habitat modification can be especially detrimental to native trout populations, the study found. These fish migrate to spawn and feed and prefer large, relatively pristine habitats that are connected without any barriers such as dams. Although the upper Flathead River system in Montana and British Columbia, Canada, is considered a regional and range-wide stronghold for bull trout and westslope cutthroat trout these populations may be threatened by the effects of 55 years of altering flow downstream of the Hungry Horse Dam.


Results of the study further suggest that dam management strategies that are more similar to the natural flow of the river will likely improve the chances of protecting habitat and help to maintain and restore bull trout and westslope cutthroat trout populations.


Analyses comparing the natural flow of the mainstem Flathead River (predam, 1929?1952) with five postdam flow management strategies (1953?2008) show that natural flow conditions optimize the threatened bull trout habitats and that the current management practices best resemble the natural flow conditions of all postdam periods, Muhlfeld said.

One caveat to this observation, said Muhlfeld, is the practice of increasing flow in the late summer to help fish species such as salmon and steelhead, known as anadromous. Because they migrate from salt water to fresh water to breed. According to the study, increasing flow to benefit one species is actually reducing the amount of suitable habitat for another ? the bull trout, a species listed as a threatened under the Endangered Species Act.

Several studies have shown that dam operations have profound effects on anadromous fishes, yet before ours, few studies have examined the impacts of flow management strategies on habitats of threatened, native trout species in the upper Columbia River Basin, Muhlfeld said.


Results from the study are featured in the April 2011 early online edition of River Research and Applications. The article is titled, "Assessing the impacts of river regulation on native bull trout (salvelinus confluentus) and westslope cutthroat trout (oncorhynchus clarki lewisi) habitats in the Upper Flathead River, Montana, USA. and can be viewed online.

Click here for more environment-related news.

Get Your Fish On.

Plan your next fishing and boating adventure here.

Recommended for You

When all else fails, here's what these pros tie on. Bass

MLF Pros: What's Your Go-To Lure?

G&F Online Staff - May 20, 2019

When all else fails, here's what these pros tie on.

Chiggers might be tiny little critters that are hard to see but they sure bring big-time misery Other Hunting

Keep Itchy Chigger Bites at Bay This Summer with Chigarid

Lynn Burkhead

Chiggers might be tiny little critters that are hard to see but they sure bring big-time...

Now that you know you might screw it up the next time a big fish bites, let's fix it. Fishing How-To

Why You'll Lose Your Next Big Bass

Larry Larsen

Now that you know you might screw it up the next time a big fish bites, let's fix it.

See More Recommendations

Popular Videos

13 Fishing Pathfinder Weedless Walking Bait

13 Fishing Pathfinder Weedless Walking Bait

Fresh off catching the biggest bass in ICAST Cup history, 13 Fishing pro Jessie Mizell shows OSG's Lynn Burkhead the new Big Squirm soft plastic worm and the company's unique Pathfinder topwater walking bait that is totally weedless in design.

Mustad Skatter Shad Bladed Jig

Mustad Skatter Shad Bladed Jig

As Mustad continues to expand into an all-around tackle company, Reid McKinstry shows off some innovative features that make the Mustad Skatter Shad bladed jig a winner in big bass waters.

Berkley

Berkley's Surge Shad

Major League Fishing pro Scott Suggs has relied on the Berkley Surge Shad lure concept for years, using similar designs to capture MLF titles and a $1 million dollar FLW Forrest Cup win. With new features in the Surge Shad, Suggs tells OSG's Lynn Burkhead that even he can find success out on the water!

See more Popular Videos

Trending Stories

 Catfish tend to be found in shallower water at night, but they are still active during the day; Catfish

Catfish Night & Day: How to Catch 'Em Both Ways

Terry Madewell - April 04, 2018

Catfish tend to be found in shallower water at night, but they are still active during the...

Here are the 10 most common reel performance problems and how to fix them. Reels

10 Most Common Reel Performance Problems

Anietra Hamper

Here are the 10 most common reel performance problems and how to fix them.

Experts agree record channel cat caught in 1949 was actually a blue catfish. Records

Upon Further Review: 70-Year-Old Catfish Record Voided

G&F Online Staff - May 22, 2019

Experts agree record channel cat caught in 1949 was actually a blue catfish.

See More Stories

More News

Readers will find new look, new features beginning in September issues. News

New Game & Fish Coming Your Way

Michael F.X. Cassidy - August 01, 2019

Readers will find new look, new features beginning in September issues.

2019 edition, now available, commemorates ethical sport and productive science. News

IGFA ‘World Record Game Fishes' Celebrates 80 Years

Jack Vitek - July 15, 2019

2019 edition, now available, commemorates ethical sport and productive science.

Jeff Kolodzinski attempted to break his own 24-hour world record for most fish caught. News

Did 'Marathon Man' Break His Own World Record?

Lynn Burkhead - September 10, 2018

Jeff Kolodzinski attempted to break his own 24-hour world record for most fish caught.

See More News

GET THE MAGAZINE Subscribe & Save

Temporary Price Reduction

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE

GET THE NEWSLETTER Join the List and Never Miss a Thing.

×