In today’s Littoral Zone episode, Phil chats with Jason Randall about what trout see and why it matters.
Jason has written four books, including his famous trout trilogy, which dives deep into how trout behave in their environment. While Jason’s passion lies in rivers and streams, the research and knowledge he’s amassed is equally beneficial to stillwater fly fishers.
His understanding of how trout see is crucial information for all fly fishers, guiding both our pattern selection and presentation techniques, information that helps us consistently make the correct pattern and presentation choice.
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Episode Chapters with Jason Randall on What Trout See and Why it Matters
2:20 – Jason Randall graduated as a veterinarian and did postgraduate work in fish health and medicine. Although he considered a career in fisheries, he ultimately chose private practice.
4:16 – Jason started fly fishing around 40 years ago but got frustrated early on due to a lack of guidance. He took a break, then later tried again this time with the help of great mentors.
Jason says his passion really started during a trip to Colorado. A guide introduced him to a caddis hatch that transformed the river into a feeding frenzy of trout. Watching the stream come alive with caddis and rising fish was a game-changer for Jason.
08:21 – Jason says he was lucky to have some amazing mentors like George Kustin who guided him in fly fishing and taught him about wet flies and soft tackles. Lefty Kreh took Jason under his wing.
09:31 – Jason also works with Temple Fork Outfitters on rod design and prototype testing. This year, they introduced a new European Nymphing Rod called the Elevare, which won Best New Rod at ICAST 2024.
Books by Jason Randall
13:00 – Jason’s trout fishing trilogy started in 2012 with Jay Nichols from Stackpole Books. The trilogy covers:
- Feeding Time: A Fly Fisher’s Guide to What, When and Where Trout Eat
- Trout Sense: A Fly Fisher’s Guide to What Trout See, Hear, and Smell
- Moving Water: A Fly Fisher’s Guide to Currents
Jason also wrote Nymph Masters, a collaborative effort featuring tips from top nymph anglers like Gary Borger and Lefty Kreh.
Trout Sense
17:00 – Trout begins life as prey, eating small organisms like plankton. As they grow, they become predators, feeding on insects, crustaceans, and even small fish or mammals.
They retain the wide-set eyes of prey for spotting threats and the sharp focus of predators for hunting. This makes them tricky to catch.
21:10 – Jason explains how light works differently underwater, which affects how trout see. Refraction, or the bending of light when it moves from air to water, can also trick us into thinking we’re casting right over a fish, but we could be a few feet off.
26:08 – Jason dives into how color fades underwater, starting with red, and how different colors are absorbed at various depths. Fluorescent colors like chartreuse stand out the most and create a strong contrast, which trout notice.
29:18 – Unlike humans, a trout’s pupils don’t adjust to light, and their eyes have a football-like shape that lets them see clearly both in front and to the side.
Search Image and How Trout Decide to Eat
42:11 – Trout uses a “search image” to figure out what’s food and what’s not. They focus on four things: size, shape (profile), movement, and color.
If a fish keeps ignoring your fly from far away, it’s probably the size or shape that’s off. But if they come close, and then turn away, Jason says that it may be a color-based refusal.