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I have Trolled Ririe for Kokanee since 2007, is it just me or have the fish been smaller lately. Granted I did not fish it this year when the three year olds were pre-spawn. I also heard IDFG gill netted some large kokes this year when they did there sampling.
What say you?
Stocking records show 2012 and prior about 200k fish per year, 2013-17 300k fish stocked per year.
Lee
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Seemed like a normal average size to me. I caught a few 14 inches this spring.
Windriver
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I would have to agree with you, the Kokanee have gotten smaller since the increased number being stocked. We used to catch 17 inch Kokes but this year I never caught anything bigger than 14 inches. A lot of water washed in plenty of feed for the plankton this spring so maybe the next class of fish will be larger. I certainly have caught more fish since the limit was raised to 15. The small fish work up nicely for the smoker. It is probably hard for the Fish and Game folks to know what is the right balance of fish to stock.
I certainly like to the Ririe fishery.
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The average years yield, adult 3 year old male in Ririe has always been under 14" with a few years exceptions. Those exceptions rely on the perfect triad of events rather than the amount of fish planted. The three effects that have to come together to make for a larger 3 year old class is as follows:
1. Heavy snow pack. The kokes feed on plankton and the amount of plankton in the lake depends heavily on the amount of nutrients and minerals carried into the lake via the snow pack.
2. Slow run-off delivery. The longer the the delivery time for the supply of nutrients coming into Ririe, the more food is produced in the biomass.
3. A gentle spring where the temperatures remain low enough for an extended period of time allowing the kokanee to remain up in the top 15' of the water column. Plankton only exists at depths where the light penetration is strong enough for it's growth. Kokanee however, do not like water temperatures above 56.5 degrees. The longer the period of time in the spring that the water remains conducive to plankton generation and the fish being able to feed for extended periods of time at or close to the surface determine the maximum growth rate for the biomass.
The other triple play that comes into context with the size of the fish is having this perfect storm happen three years in a row. Lose one year of growth which is normal and we are back at fish from 12 to 14 inches.
Since Ririe is a narrow and fairly deep gorge, most of the food in the biomass goes unused as the heat is reflected from the sides of the canyon into the water and warms it up faster then the kokes ability to stay near the surface and feed. I believe this is why the F&G biologists saw no harm in planting more fish as a plankton concentration study probably saw no change with the increased numbers of fish planted.
Hope this information helps to understand the complexities of Kokanee growth rates.
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Great information, Thanks. I'm sure the Game and Fish people are on top of the situation and are managing with the best intent.
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[left]Great topic! IDFG has been adjusting stocking rates over the past decade, trying to find the best balance between fish size and angler catch rates. As has been pointed out previously, kokanee size can be heavily dependent on the number of fish in the reservoir, with high densities (higher stocking rates) producing smaller fish but higher catch rates for anglers. Fewer stocked fish generally results in faster growth and larger size, but fewer fish caught by anglers. Other factors play a role in kokanee growth as well, so it's not solely the number stocked that influence catch rates and growth, but stocking/fish density does play a large role. [/left]
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[left]Prior to the mid-2000's we only stocked 70k kokanee, which wasn't enough fish to get anglers excited and produce high catch rates. Around 2007, we increased our stocking to 210k, which improved angler catch in subsequent years. We increased that number again in 2013, looking for the sweet spot between catch rates and fish size. Our goal as written in our [url "https://collaboration.idfg.idaho.gov/FisheriesTechnicalReports/Fisheries%20Management%20Plan%202013-2018.pdf"]Fisheries Management Plan[/url] is to provide at least 1 kokanee per hour of fishing, and to evaluate catch rates and fish size to optimize the fishery. Our most recent creel survey shows we are at 1.01 kokanee caught per hour, so we're doing OK there with regards to catch rates. Prior to the increase in the stocking rates, we were not meeting the objective of 1 kokanee per hour. [/left]
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[left]We will be working on updating our Fisheries Management Plan over the coming winter, and welcome any input you guys have on the Ririe fishery, particularly the topic of size and catch rates for kokanee. Please send comments to the Ririe Fisheries Biologist, Jon Flinders at [url "mailto:jon.flinders@idfg.Idaho.gov"]jon.flinders@idfg.Idaho.gov[/url] [/left]
Dan Garren
Regional Fisheries Manager
[url "mailto:dan.garren@idfg.Idaho.gov"]dan.garren@idfg.Idaho.gov[/url]
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If I could only catch 1 Kokanee an hour I'd quit fishing for them. SMH
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