Take care of the fish, and the fishing will take care of itself.
Copyright 2014 East Yellowstone Chapter Trout Unlimited. All rights reserved. P.O. Box 3008, Cody, WY 82414
Update, Dec 2013
Update, Nov 2013
Update, May 31, 2013
Update, February 2013
Lake Trout Animation
Update, September 2012
Update, July 2012
Update, June 2012
Assessment: Report to
the Superintendent YNP
August 4, 2011
Information Sheet, USGS
Comments April 2010
Lake Trout Symposium
Final Report 2008
Dr. Robert Gresswell
|Background - Yellowstone Lake /Yellowstone Cutthroat Trout Status January 3, 2012|
The Yellowstone cutthroat trout (YCT) now occupy less than 43%
of their historical range; in addition, they are significantly
hybridized in 1/3rd of the remaining.
The Yellowstone Lake/upper Yellowstone River system (YL) was
once home to an estimated 4,000,000 YCT. It was considered a
stronghold for genetically pure YCT’s and was considered
relatively safe from the impacts of climate change. In addition, it
was considered a Keystone species for the entire ecosystem; 40
other species are dependent on YCT.
||Lake trout (LT) were officially discovered in 1994. They are
overwhelmingly the most significant threat of the triple threat to YCT
subsistence: lake trout, drought, and whirling disease.
The NPS has been employing gill netting since 1995 and currently
spend $1M annually on the effort. To date a total of over 800,000 LT
have been netted; 220,000 in 2011 alone. The LT population is now
estimated at 3-400,000 adult fish.
The current YCT population is unknown; but is certainly no more than
10% of historical, probably <5%.
The YCT population in this system cannot be lost; and need not be
lost. A Scientific Review Panel in 2008 made 4 major
recommendations to NPS. These were renewed in June of this
year. Basically, these recommendations require increased
suppression (netting) of LT, while developing scientific approaches
to population estimates of both species, movement patterns of LT,
LT spawning site identification by a robust telemetry study,
experimentation with alternative technology to target LT eggs, and
periodic review by the scientific community.
Major strides have been made in the past few years by the NPS in
their approach. Yellowstone Park administration changed over the
winter with Daniel Wenk being named Superintendent. A
comprehensive fisheries management EA was published which
sets benchmarks for LT removal and YCT recovery.
The NPS netting effort was significantly increased by the hiring
of a commercial fishing crew from Wisconsin. The NPS has
formed an alliance with outside governmental agencies and
with NGOs (Trout Unlimited, Greater Yellowstone Coalition,
National Parks Conservation Association) to tackle the problem,
including the acceptance of financial support and input. The
USGS began a major research effort in 2008 to identify
alternative suppression technology – targeting recruitment.
Some of that technology is now ready to scale-up. Electro-
shocking of LT eggs was used this past fall for the first time on
Lake Pend Oreille. Results of that study are due this winter.
The most significant advancement has been the start of a three
year hydro-acoustic telemetry study as a joint effort of all parties
to identify lake trout movement patterns and spawning beds.
The key to YCT recovery is major suppression of LT (they will probably
never be eliminated) while at the same time, cutting off recruitment into
the LT population. Central to this goal, is to know the location of their
spawning beds and movement patterns, thus a hydro-acoustic study
was initiated on August 16, 2011. A total of 141 hydro-acoustic tags
were surgically implanted into lake trout.
||Yellowstone Lake Receiver
Click map to enlarge.
Implanting hydro-acoustic tag
into lake trout "Judas Fish".
|Movements of these fish are being monitored by 40 receivers
strategically located around the lake. Data will be analyzed this
winter and reported in February at a meeting of the Yellowstone
Lake working group. This 3 year telemetry effort requires a
significant NPS, USGS and NGO commitment of money, research
time, and support.
|Trout Unlimited, the National Park Service, the US Fish & Wildlife
Service, and the US Geological Survey are partnering to fund
research by Montana State University/USGS/USFWS to investigate
and develop alternative methods to reduce or eliminate the Lake
Trout in Yellowstone Lake.
||Sponsor a "Judas Fish" and track it on line...
Donate a Lake Trout telemetry tag ($400) for Yellowstone Lake
||100% of your tax deductible contribution goes to the study.
Make Checks payable to "Save the Yellowstone Cutthroat".
Send to: Trout Unlimited, P.O. Box 3008, Cody, WY 82414.
For more information please call Dave Sweet, campaign coordinator, (307)527-9959.
||Watch telemetry traces on USGS
| New UW Research Shows Grizzly Diet Shift Hits Elk
May 15, 2013 — A decline in native Yellowstone cutthroat trout
due in part to the introduction of nonnative lake trout has driven
a shift in the diets of grizzly bears that helps explain losses in
some migratory elk herds in the greater Yellowstone area,
according to new research published today. read more
Fewer Trout means less food for YNP Raptors
May 13, 2013 - In an ecological chain reaction, an
overabundance of non-native mackinaw in Yellowstone Lake is
hurting the cutthroat trout population, which in turn makes slim
pickings for osprey. read more
Yellowstone Lake Update for “The Trout Tale”
When the East Yellowstone Chapter in Cody entered into the fight in the fall of 2007 to “Save the Yellowstone Cutthroat” of
Yellowstone Lake, they had no idea how big the project would get or how long it would take to start seeing a recovery.
After all, this is a simple problem. All you have to do to recover the cutthroats is to get rid of the lake trout that were
somehow introduced into the system. Seems like a pretty simple solution. The strategy also didn't seem too tough – just
net out the majority of the adults and keep the rest from successfully spawning. But, 6 years later we are much wiser than
we were back then.
The road has been long, sometimes difficult, sometimes frustrating, but always rewarding. The greatest rewards have
been seeing the incredible support that fellow TU members, anglers, sportsmen and women, conservationists, and
agency folks have demonstrated for this iconic ecosystem. With only a few exceptions, the vast majority of people that we
have met refuse to accept as inevitable, the loss of this population. They have been willing to argue for its survival and to
put their energy and their resources into the effort.
The struggle is far from over; but after 6 years and a huge concerted effort by all involved, we may finally be on the brink of
a “recovery”. The Yellowstone National Park fisheries folks will admonish me for being too optimistic, but I can’t help
myself. All one has to do is look at the results of this past summer’s work on the Lake to understand my optimism.
The netting crews again netted just over 300,000 lake trout. How can that be a good sign? Well, it took about 28% more
effort to capture those lakers in spite of new telemetry data that helped guide those netters to the fish. This is the second
year in a row that the CPUE (catch per unit effort) declined significantly. The crews continue to pursue the lakers wherever
they go in the lake. They even set up what was called the “Berlin Wall” of nets around Carrington Island, where lakers are
known to spawn and captured many potential spawners. Even the government shutdown didn’t stop the netting as
Superintendent Wenk considered this activity a “critical” service.
Meanwhile, a mark/recapture study of lake trout was conducted to finally get a true population estimate. Although the
analysis isn't complete, I can tell you that 56% of the marked fish were recaptured (netted) after marking. This is very
The telemetry study really got going full stream this past summer as a full time statistician and a technician were hired to
run the study and analyze the data. Not only were these data used to guide the netting; but they were used to identify three
more potential spawning areas on the Lake in addition to Carrington Island. In September, these areas were covered up
in massive receiver arrays know as VPS arrays so that detailed mapping of lake trout movements within the areas could
be accomplished. A total of over 125 borrowed receivers were used in these arrays. In contrast, in 2012 the Carrington
Island array had 9 receivers. Although the data have not yet been analyzed, I’m confident that any spawning grounds
within the boundaries will be pinpointed.
Also this past fall, the known Carrington Island spawning bed was a test site for placing egg collection baskets into the
substrate. Data from these baskets will be used to learn a great deal about deposition into the substrate, hatching
survival, and the ability of electro-shocking to kill those eggs. This last study phase was interrupted by the shutdown but
the researchers spent the time on Swan Lake in Montana doing similar studies there which will be applicable to
All of this increase in activity would not have been possible without the tremendous support that the study team received
from the Wyoming Wildlife and Natural Resources Trust committee. This group toured the Lake in June and
subsequently awarded the effort $150,000 for the 2013 work. And more importantly, they urged us to submit a grant for the
balance of the next three years. We can’t thank them enough.
And finally, the real reason for my optimism is that we are seeing a positive response in the cutthroats. Many indicators
point to a small but consistent and meaningful rebound. Most telling is the distribution netting numbers for the natives.
For the second year in a row, the overall numbers are up; but more importantly, the numbers of surviving juvenile
cutthroats have shown significant increases. This is what we all have been striving for.
I wish I could say our work is done; but it’s not. We can’t let up. To slow down now would only allow a reversal of our
progress. More money has to be raised to continue the work. More nets must be set to continue the downward lake trout
population. More transmitters have to be inserted to monitor movements. More receiver arrays have to be established to
be sure that we know “all” of the lake trout spawning areas. And, we have to continue to pursue egg and fry suppression.
Lastly, we have to ensure that the public understands why we are removing lake trout to save the native cutthroats. And,
we have to ensure that the governmental agencies continue to be funded for this effort. This public relations part of the
project has sometimes been the most challenging. A small, but vocal group determined to let the lake trout take over in
Yellowstone Lake, has challenged the costs and direction of this project. We cannot afford to let them succeed. To that
end, it is important that our legislators hear support for this project and we can use your help. You can help by writing to
our legislators at the addresses below to voice your support for the direction the NPS is taking. Details on how you can
support the project can be found on our www.wyomingtu.org website. Please write your letters today!
Senator Michael B. Enzi
379A Russell Senate Building
Washington, DC 20510
Senator John Barrasso
307 Senate Dirksen Building
Washington, DC 20510-2603
Representative Cynthia Lummis
113 Cannon House Office Building
Washington, DC 20515
Update - Electroshocking to induce mortality of lake trout embryos on Carrington Island,
Since lake trout were first discovered in Yellowstone Lake in 1994, gillnetting has been the primary tool used to
suppress the population and conserve the native Yellowstone cutthroat trout. In recent years, large live entrapment
nets, set by contract netting crews, have also been used to target the large lake trout. Although it appears the
netting efforts applied in 2012 and 2013 have curtailed lake trout population growth and the Yellowstone cutthroat
trout may be rebounding, these trends will only continue by maintaining high levels of lake trout suppression
through the coming years. In 2014, the lake trout netting alone, using four large boats and contract crews, will cost
nearly $2 million. These costs are expected to increase annually.
To reduce costs and ensure program viability into the foreseeable future...read more
Click image to
Yellowstone Is Saving Native Trout With Lessons Learned From
(Gasp!) The Commercial Fishing Industry
Read Forbes article
2012-13 Lake trout population estimates show decline
Lake Trout population declined by 15% during the 2012-13 season as reported by Pat Bigelow, fisheries
Wyoming Ligislature passes bill supporting lake trout study in Yellowstone Lake
SF 82 guaranteed continued funding of studies for the lake trout mitigation in Yellowstone Lake. Over
$620,000 will be availble for Save the Yellowstone Cutthroat efforts through the Wyoming Wildlife and Natural