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Yakima River
Trout Population
Our
catch on the Yakima River is composed predominantly of Rainbow Trout
with a few Cutthroat mixed in as well. In the Lower Canyon, expect to
catch about 90% Rainbows and only a few Cutts. As you move
upstream the ratio of Rainbows to Cutts increases to about 15% in the
Farmlands, and to about 30% in areas surrounding Cle Elum. A rough
estimate of our catch is that 60% of the trout range 10-14", 25%
range from 14-16", 10% range from 16-18", and 5% are 18" plus. It
obviously varies by section, day, and angler skill and strategy.
Some days are filled with big fish while others seem to be filled with
little guys - that is the beauty of wild trout fishery! Hopefully
this generalization is useful for you when planning your next trip to
the Yakima. Population estimates from the
Washington Department of Fish and Wildlife are listed below.
In addition to Rainbow Trout, a nymph fisherman will catch good numbers
of Mountain Whitefish, a native species to the Yakima River. There
are also Suckers, Northern Pike Minnow, Chinook Salmon, Silver Salmon,
and a few Steelhead as well. Bull Trout, Lake Trout, and even
Brook Trout are caught in the Yakima River system on rare occasions.
They are extremely rare but it just goes to show - you never know what
might wind up on the end of your line!
State of Washington
DEPARTMENT OF FISH AND WILDLIFE
Ecological Interactions Team,
201 N. Pearl St. Ellensburg, WA 98926
Summary of Upper Yakima River Rainbow Trout Status
Estimates For Sep/Oct 2003
Abundance of Fish Over 4" in Length
Average number of Rainbow Trout per river mile: 677 fish.
Most abundant is the Lower Canyon section with 1129 / river mile.
Least abundant is the Thorp section with 244 / river mile.
Total estimate of Rainbow Trout abundance from Roza Dam to the Cle Elum River confluence:
39,218 fish.
Size
The average length of Rainbow Trout (fork length): 9.8".
The average length of Rainbow Trout over 10" (fork length): 11.5".
The Cle Elum section had the largest average sized fish (of fish > 10" FL).
The Thorp section had the smallest average sized fish (of fish > 10"FL).
The average sizes of rainbow trout decreases as you move upstream with the exception
of Cle Elum. However, the average size of fish over 10" decreased, with the exception of Cle Elum.
The largest Rainbow Trout observed this year was in the Cle Elum section and was 21.4" long (total length)
Distribution
The Lower Canyon and Ellensburg reaches contained the largest number of fish per mile in 2003.
The following equation was developed to calculate the weight of a mainstem Yakima
River Rainbow Trout from a measured fork length (in inches). This equation is based on
the lengths and weights taken from over 21,500 fish. With this technique, you can
calculate the weight of a fish you caught while minimizing the amount of handling on
that fish.
Weight in lbs. = 0.0005 x (measured fork length in inches) ^ 2.9298
WDFW Ecological Interactions Team
Many hand held calculators have a button labeled y^x . To use this function, you enter
the fork length you measured into the calculator, then press the y^x button once, and
enter 2.9298, then press the = button. Next press the multiplication, or X button once,
and enter 0.0005 and then press the = button. The result is the weight of the fish in
pounds. For example, the weight of a 14.5" Rainbow Trout would be:
Weight in lbs = 0.0005 x (14.5) ^ 2.9298 = 1.2634 or about 1.3 lbs
For more data see:
Yakima River rainbow trout population.
Also, detailed information including WDFW annual reports is available in PDF format at
www.ykfp.org.
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