by Lou Smith, March 11, 2013

This is an attempt to help beginning Kokanee fishermen/women understand what the seasoned pros already know. They understand the yearly cycle of a kokanee lake. I will attempt to consolidate what my literature search found in an outline form that avoids the long boring reading that has possibly keep a lot of people from reading them. But, I earnestly encourage you to read all the selected items listed at the end.

After taking a renewed interest in fishing to fill time created by retirement, I joined Washington Lakes.com and read fishing reports for all the lakes within an hour’s drive. Of particular interest were year-round lakes. It didn’t take too long to discover American Lake near Tacoma. It was big, but not too big for my little boat, and deep enough to not get too hot for most fish. Then I found other kokanee lakes near me: Clear (Pierce Co.), Alder (Pierce), Wilderness (King), and Meridian (King). With time, I settled in on American, Clear and Alder. Each lake had its own character and what worked on one lake didn’t necessarily work well on another. It wasn’t long before I was hooked and considered myself a “kokaholic”. You know you are one when you catch a rainbow and say “Darn, it’s just a bow”. Coming from a scientific background, I have a need to know everything possible about things that I do. The hardware (boat, downriggers, fish finders, rods, reels, line, attractors, and lures) is all very well documented. What I needed to know was “where should kokanee be and why should they be there?”.

After Googling “kokanee”, there was no shortage of articles, fishing reports, and videos. I soon discovered that the best kokanee fishermen, tackle manufactures and lakes were right here in our backyard – California, Oregon and Washington. I lived in California for 20 years (’89 -’09) within an hour’s drive of Pardee, New Melones, and Don Pedro, but wasn’t fishing due to work. In hindsight, it would have been great to have met the legendary Phil Johnson on Don Pedro. Phil’s pioneering kokanee fishing techniques are still used today and are practically unchanged from his early ‘90s studies (see reference at end).

Many times I would read fishermen’s posts that asked “Why doesn’t this lake have more kokanee?”, or “I can’t catch any, where did they go?”, or “Why doesn’t the State put more kokanee in this lake?”, or “I can see plenty of fish on the screen, but why aren’t they biting?”. Well, I have to admit that I often asked myself the same questions. After a lot of reading, I came upon a few articles that answered these questions. The pertinent information was there, but in my haste to finish the article I skipped over the “boring” stuff as others readers probably did. So, I went back and read them again; slowly and every word. Bingo! – there it was in the “boring” stuff that I had skipped over – the answers to my questions.

Temperature:
• Temperature is probably the one single most important factor to finding kokanee.
• Kokanee love and seek out 54 degree water, but are found between 44 and 59 degrees.
• Kokanee can go into warmer water for short periods to feed, but temps above 60 can be harmful, even lethal with time.
• Temperature stratification (layering) is caused by sunlight and water clarity (mostly silt and plankton).
• The ideal 54 degree strata seasonally moves down the water column.
• Every lake fisherman should have an underwater thermometer in his tackle box (Deptherm by Vexilar, ~$10).
Plankton and other food:
• Early spring: kokanee school in warmer shallow water and feed on flies, larvae, etc.
• Later spring the phytoplankton bloom. Without plankton there would be no kokanee
• Daphnia (water fleas) are an important food for kokanee. They are light-sensitive and drop down the water column in spring.
• Kokanee feed on plankton filtered by their gill rakes.
• Phytoplankton:
o The plant form that is the bulk of a kokanee’s diet.
o It is light dependent and does not move on its own.
o Cannot grow when light levels at depth drop below 10 percent of surface light
• Zooplankton:
o Is an animal plankton that also feeds on phytoplankton.
o They are kokanee’s biggest competitor for phytoplankton.
o They can move up and down the water column on their own.
o Once zooplankton are plentiful, kokanee spread out over the lake.
• Mysis shrimp
o Absolute enemy of kokanee
o Compete with kokanee for phytoplankton and zooplankton
o Heavy populations of Mysis shrimp can eliminate food supply for young kokanee, affecting survival.
Critical temperature/plankton requirements:
• As long as the ideal 54 degree depth remains above the 10 percent light-limiting depth for phytoplankton growth, the kokanee are in heaven.
• When the 54 degree depth drops below the 10 percent light, there is no growing phytoplankton (see why you need a thermometer?). I don’t know about your fish finder, but I learned how to tune mine (Humminbird 561) to show the plankton growth, the thermocline and a clear screen below the plankton growth limit from forum/blog posts on WashingtonLakes.com.
• Now the phytoplankton food source is in temperatures harmful to kokanee.
• (repeated here for emphasis) Kokanee can go into warmer water for short periods to feed, but temps above 60 degrees can be harmful or lethal with time.
• Kokanee will then stop eating and growing (kokanee can grow ~1 inch/month with abundant food).
• This triggers the pre-spawn period when they start to school up again.
Why some lakes have bigger (or smaller) kokanee:
• The longer the 54 degree temperature zone stays within the plankton growth zone, the larger kokanee can grow.
• This is affected by intake water temp, lake depth, ambient temperature, and amount of sunshine.
• Even in ideal conditions, there can be downsizing (stunted growth) caused by too many fish for the food supply (a reason why limits are increased on some lakes to 10, 15, even 25 per day).

Each kokanee lake has its own conditions. The inflow temperature, spawning success, ambient climate, water quality (chemistry), nutrients for plankton growth, mysis shrimp, depth, natural predators, etc. You can see how many variables there are that have to come together for an ideal kokanee environment. This is the reason that every season on the same lake can be very different. When you conduct a temperature profile of your favorite lake, do not assume it will be the same over the whole lake or even week-to-week. There can be deviations around inflow and underwater springs that you may not know of.

I can’t remember where I read it, but a fisherman claimed that all he needed was a thermometer to catch kokanee because “you don’t see the fish that are striking from just outside the narrow ‘cone’ of your fish finder”. You could drag and change your setup around all day in 54 degree water that is below the10 percent light limit and all you will catch is a dumb stray kokanee and you might even eventually limit! In the past, the stubborn me has done this on American Lake for 10 hours and caught one kokanee! Now I know better.

This article was not intended to cover everything in the title, just the basics that might urge you to find out more and catch more kokanee. I look forward to constructive criticism and new info/sources. After all, I want to learn more and catch more kokanee, too. Hope this helps to shorten the learning curve of at least one fisherman.
Tight lines and see you on the water!
Lou

For more detailed information, please consult the best of many sources I have found so far:
• Catching Large Kokanee by Phil Johnson & Phil Pirone. Free download at www.Kokaneepower.org/articles/3.pdf
• The Kokanee Obsession by D. Kent Cannon. Order his book at: nwoutdoorwriter.com. Sign up for his free weekly e-mail newsletter and get $5.00 off book coupon.
• Kokanee University by Gary S. Gordon. Free download at fishwithgary.com
• Also, why not join WashingtonLakes.com (free) for fishing reports, bathymetric maps of over 350 lakes, videos, forums and a ton of other info?