Yellowstone River situation – From Chris Wood

AZcounsil-logo-100x100Posted on Trout Unlimited Open Forum
August 30, 2016

Yellowstone River Situation

From: Chris Wood
Sent: Friday, August 26, 2016 11:47 AM
To: All Trout Unlimited Employees
Subject: Yellowstone River situation


As you have likely heard, Montana Fish Wildlife and Parks recently closed 183 miles of the Yellowstone River due to an outbreak of Proliferative Kidney Disease (PKD). PKD is a parasite that can infect and kill fish.  PKD has only been found twice in MT. This time is has killed an estimated 30,000 mountain whitefish.

We know that Yellowstone River is flowing at near historic lows, due to poor snowpack and a dry summer, and that until water temperatures drop consistently below about 55 degrees Fahrenheit, the parasite will likely continue to infect fish.  Water temperatures dropped below 55 degrees early Thursday morning for the first time.

Montana staff have taken a very measured and science-based approach in dealing with this outbreak. The rumor of this being the end of the Yellowstone fishery is overblown and not true. The fact is, prior to the PKD outbreak, the Yellowstone was (and still is) one of the healthiest rivers in the country. Even healthy rivers face setbacks.

While there has certainly been a toll, both to fish populations and the local economy, the fishery will undoubtedly bounce back. What is important right now is to focus on collecting data and making decisions based on the best available science and while employing the precautionary principle to do no additional harm. To date, there appears to be very little impact to wild trout. The impact to mountain whitefish populations is less clear at this point, but it renews the call for more monitoring of this species.

Over the past two weeks, Montana Fish Wildlife and Parks has been working very hard to gather data to help determine when the river and its tributaries can be re-opened.

So, what can we do about it?

First, keep at it. Our mission is to make rivers resilient and healthy. By securing instream flow leases and engaging in habitat protection and restoration, TU has been instrumental to improving the Yellowstone for decades. The reason that our work to protect, reconnect, and restore rivers is so vital is that a healthy and resilient river will recover from a hit like this. And as the climate continues to change, these hits will keep coming.

Second, preach the gospel of Inspect, Clean and Dry. While Aquatic Invasive Species, PKD included, can be introduced into rivers in a number of ways, be they by bird or by boot, we need to do our part to limit their spread.

Finally, the annual meeting is in Bozeman, and many members will want to fish there at the end of September. While portions of the Yellowstone closure may remain in effect, there are many other top-notch angling opportunities nearby, including the Gallatin Canyon, Madison River, East Gallatin, and many more within an hour’s drive.

Below you will find more detailed information on the outbreak. Information will continue to be posted to as we learn more. If there are further questions, please feel free to contact me, Bruce Farling ( or Pat Byorth (

Thanks and have a great weekend.

Chris Wood / President and CEO / c: 571-274-0601
Trout Unlimited
o: 703-284-9403

The Outbreak:

·      The Yellowstone River, a crown jewel of wild trout fisheries, is suffering an unprecedented disease outbreak of Proliferative Kidney Disease, driven by a parasite specific to salmonids. Tetracapsuloides bryosalmoninae is a complex two-host parasite that is emitted from bryozoans, a jellyfish-like colonial invertebrate that attaches to rocks looking like amorphous blobs or mini staghorn coral.  Once the parasite leaves the bryozoan host, its infective spores have about 24 hours to find a trout or whitefish.

·      In the past 10 days, state biologists have counted more than 3,000 dead mountain whitefish and less than 10 rainbow and cutthroat trout.  Biologists estimate the actual mortality could be as high as 30,000 whitefish.

·      Montana FWP closed 183 miles of the Yellowstone River and all tributaries between Yellowstone National Park in an abundance of caution to prevent inadvertent spread of the disease.

·      PKD has only been detected in Montana twice, and neither caused an outbreak of disease.

·      The Yellowstone River is flowing at near historic lows, due to poor snowpack and a dry summer.

·      Until water temperatures drop consistently below about 55 degrees Fahrenheit, the parasite will continue to infect fish.  Water temperatures dropped below 55 degrees early Thursday morning for the first time. Generally water temperatures moderate in the Yellowstone by mid-September.

·      Portions of the closure will be lifted as scientific data dictates.  The science is, and should, drive the process to ensure this treasured fishery can recover quickly.

Additional points:

·      The Yellowstone River is one of Montana’s healthiest rivers and is the longest free-flowing stream in the continental United States, supporting a largely intact native fish assemblage including mountain whitefish and Yellowstone cutthroat trout along with introduced wild rainbow and brown trout.

·      Healthy rivers and streams are resilient to insults like drought and disease. Tributaries are vital refuges and spawning areas and floodplains are the sponges that keep water clean and cold through the summer.

·     Since the late 1980’s FWP and Trout Unlimited have been working to change Montana Water law to allow leasing of water rights to maintain year-round flow in tributaries which are vital spawning and rearing streams for native and wild salmonids and provide refuge during stressful time.  To date, FWP and TU hold instream flow water leases on five key tributaries in the Yellowstone and Shields drainage and the Montana Water Program has another four projects coming on line. These leases successfully restored healthy spawning runs and increased populations of Yellowstone cutthroat trout.

·      In addition to water leases, FWP and TU have engaged in dozens of habitat restoration projects in tributaries of the Yellowstone, building resiliency into the system which will ensure the river quickly recovers from the outbreak.

·      The Yellowstone River and its fishery generate more than $20 million in economic activity.  The outbreak is having an economic impact on the community which is direct evidence of how important a healthy river is to the local economy.

·      To ensure the river recovers quickly, two things are required:

o   Clean, inspect, and dry all fishing equipment and boats, each time you leave a river.  This is the best way to avoid spreading disease and invasive species

o   Continue to support TU’s work to restore stream flows, healthy habitat and fish passage on the Yellowstone and all of our rivers and streams.  A healthy stream lined by dense riparian vegetation with unobstructed floodplain and healthy tributaries is the key to resilient fisheries that can quickly recover from catastrophes like disease and drought.