Massive Montana Fish Kill

(Enterprise photo by Hunter D'Antuono)

Alarming news from the American West this week — reported by Reuters and the Associated Press, a 186 mile stretch of the Yellowstone River in Montana and it's tributaries have been closed by officials after a massive fish-kill that is being attributed to an aquatic parasite.  Over 4,000 Mountain Whitefish and a smaller, undetermined number of trout have been found dead.

As quoted from the Livingston Enterprise, "Test results from samples sent to the U.S. and Wildlife Service Fish Health Center in Bozeman show the catalyst for this fish kill to be Proliferative Kidney Disease — one of the most serious diseases to impact whitefish and trout. The disease, caused by a microscopic parasite, is known to occur in Canada, the U.S. and Europe. It has been documented previously in only two isolated locations in Montana over the past 20 years. Recent outbreaks have occurred in Washington, Oregon and Idaho. In trout, research has shown this disease to have the potential to cause 20 to 100 percent mortality. The parasite does not pose a risk to humans."

"The Montana Department of Fish, Wildlife and Parks (FWP) is implementing an immediate closure of all water-based recreation (fishing, wading, floating, tubing, boating, etc.) on the Yellowstone River and its tributaries from Yellowstone National Park's northern boundary at Gardiner to the Highway 212 bridge in Laurel, according to an FWP news release."


Tetracapsuloides bryosalmonae — the organism that causes Proliferative Kidney Disease in Whitefish and trout — is a myxozoan parasite of salmonid fishes.


The intention of the restriction on activities is intended to curb the potential spread of the organisms on contaminated items.

In the 1990's in Colorado, another related piscine disorder — Whirling Disease — was spread throughout waterways via myxosporean parasites that attached themselves to felt soled wading boots used by traveling fishermen.

Toxic chemical spills are generally thought to be the more common cause of large fish mortality events, but pathogenic organisms are capable of moving through aquatic environments with surprising speed as well. The outbreak has not escaped the attention of state regulatory agencies.

"This kill is unprecedented in magnitude. We haven't seen something like this in Montana," Fish, Wildlife and Parks spokeswoman Andrea Jones said in Associated Press coverage of the issue.


While biologists are monitoring the environmental impacts, elected officials are weighing the potential economic ones — and the costs of a lack of response. AP coverage again reports,

"A threat to the health of Montana's fish populations is a threat to Montana's entire outdoor economy and the tens of thousands of jobs it sustains," said Gov. Steve Bullock, noting that Montana's outdoor recreation economy is responsible for more than 64,000 Montana jobs and nearly $6 billion in yearly economic activity. "We must be guided by science. Our state cannot afford this infectious disease to spread to other streams and rivers and it's my responsibility to do everything we can to stop this threat in its tracks and protect Montana jobs and livelihoods."

The closure could potentially last for the remainder of the season if river water temperatures don't cool, which would reduce stress on fish populations. Currently extending to hundreds of miles of waterways that feed into the Yellowstone, including the Boulder, Shields and Stillwater rivers, FWP will continue to monitor the river and will lift the closure when stream conditions improve and fish mortality ceases.


Get Your Fish On.

Plan your next fishing and boating adventure here.

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

Recommended Articles

See More Recommendations

Popular Videos

Fly Fishing for Taimen in Mongolia

Fly Fishing for Taimen in Mongolia

Finding giant Mongolia taimen and a state of enlightenment.

Bahamas - Bonefish

Bahamas - Bonefish

Conway casts for his personal best bonefish while fishing the Grand Bahama islands.

Casting Backhand in Tight Quarters

Casting Backhand in Tight Quarters

A backhand cast is when you use your backcast to deliver the fly.

 Getting Started In Fly Fishing

Getting Started In Fly Fishing

Getting Started In Fly Fishing

See More Popular Videos

Trending Articles

Fly-Fisherman Editor Ross Purnell shares his top five best trout fishing destinations in the world. Worldwide

5 Best Trout Fishing Spots in the World

Ross Purnell, Editor

Fly-Fisherman Editor Ross Purnell shares his top five best trout fishing destinations in the...

As you explore your home water, keep in mind what they are eating to select the best carp flies! Flies

The 15 Best Carp Flies

Jay Zimmerman

As you explore your home water, keep in mind what they are eating to select the best carp...

Golden riches in Wyoming's high-country heaven of the Wind River Range. United States

Wind River Range Wyoming

Greg Thomas - July 27, 2015

Golden riches in Wyoming's high-country heaven of the Wind River Range.

George Daniels offers his advice on which types of fly-fishing leaders are best for the most common applications you'll encounter on the water. Beginners

Picking the Perfect Fly-Fishing Leader

George Daniel

George Daniels offers his advice on which types of fly-fishing leaders are best for the most...

See More Trending Articles

More Industry

A train derailment spilled some 4,000 gallons of diesel into the West Branch of the Delaware River. Industry

Train Spills Fuel Into the Delaware River

Rob Jagodzinski - August 13, 2018

A train derailment spilled some 4,000 gallons of diesel into the West Branch of the Delaware...

It began with love of a river that he fished as a boy with his father, and a passion for the sport that still endures today. Industry

Abe's Fly Shop Turns 60

Jay Walden - February 22, 2019

It began with love of a river that he fished as a boy with his father, and a passion for the...

The fly fishing communities in the U.S. and Belize are mourning after twin slayings that occurred on what appeared to be a routine guide trip on Sunday, June 23, 2019 in a shallow lagoon near San Pedro, Brazil. Industry

Fly Fishing Community Stunned by Twin Slayings on Belize Saltwater Flat

Fly Fisherman Online Staff - June 27, 2019

The fly fishing communities in the U.S. and Belize are mourning after twin slayings that...

See More Industry

GET THE MAGAZINE Subscribe & Save

Digital Now Included!

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE

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

Get Digital Access.

All Fly Fisherman subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit mymagnow.com and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now