Episode Details

#708 Show Notes: https://wetflyswing.com/708

Presented By: TroutRoutes, On DeMark Lodge, Stonefly Nets, Grand Teton Fly Fishing

If you want to have more success fly fishing lakes, you need a good understanding of how lakes work—knowing how lakes work helps you get to the right spot at the right time, no matter the season.

You've probably heard the saying that 90% of the fish live in 10% of the water, and it's true for lakes just like rivers and streams!

In this two-part series on how lakes work, Phil Rowley and Brian Chan break down everything you need to know about fishing lakes effectively.

About our Guest

Brian has spent over 30 years as a fisheries biologist for the provincial government, specializing in managing trout lakes in the interior regions of British Columbia. Over the years, he worked on hundreds of lakes, managing them, stocking them, setting regulations, and carrying out habitat protection and enhancement work.

Brian is also an ambassador for several fly fishing and boating companies, including Scientific Anglers, Sage Fly Rods, Islander Reels, Marlin Boats, Semperfli Fly Tying Materials, and Daiichi Hooks.

He is a passionate fly fisher and fly designer, and together with Phil, they've put their expertise to good use through their online fly shop.

Check out Brian and Phil's Stillwater Fly Fishing Store.

Episode Chapters with Brian Chan on How Lakes Work

Lakes aren't all the same, and knowing how they work is key to becoming a better stillwater angler. Here's what you'll learn in this episode:

Lake Productivity and pH

Three Lake Classifications

Different Zones in a Lake

Lake Productivity and pH

pH is a scale that measures how acidic or alkaline a lake is, with 1 being super acidic and 14 being super alkaline. The pH level affects the water chemistry, impacting how well the lake supports aquatic life, from insects to fish.

What's the Ideal pH for Trout Lakes?

The best pH for trout lakes is between 8 and 9.2. This is the sweet spot for plant growth and lots of invertebrates, which are food for trout. If the pH exceeds 9.2, the water becomes too salty for trout, and it would not be easy for them to survive.

For example, lakes like Pyramid Lake have a pH above 9, which is perfect for Lahontan cutthroat trout but challenging for rainbow trout. The pH scale is logarithmic, meaning small changes in pH can make a big difference in fish survival.

Brian explains that pH levels in lakes aren't always the same and can change over time due to several factors:

Spring snowmelt helps keep lakes balanced by flushing in nutrients, but the lake can get too salty without it.

Human activities like logging can change water flow and impact the lake's chemistry.

Climate change is also a significant factor, as some areas aren't getting the same snowmelt they used to, causing pH to rise.

Marl and Chara Shoal

How Lakes Work: Three Lake Classifications

Lakes can be divided into three categories: oligotrophic, mesotrophic, and eutrophic. These classifications help us understand which lakes are better for fishing and support healthy fish populations.

Knowing the type of lake helps anglers figure out why one lake might be an excellent spot for big trout, and another might not be as productive.

Oligotrophic Lakes

Oligotrophic lakes are big, deep, and well-oxygenated, with lots of water flowing in and out. The flushing rate in these lakes is high, meaning the water changes quickly, so there isn't much shallow w