Fish Eyes

Science says there's no easy answers to the question: What do fish see?
Mail Tribune illustration by Paul Bunch

More than three decades of designing and testing lures for the tackle industry has proven to Buzz Ramsey what his favorite colors are for lures meant to catch salmon, steelhead and trout.

But he doesn't have a clue whether the fish he stalks share his views.

"I don't really know what they see," says Ramsey, brand manager at Yakima Bait in Washington. "But I know they see it."

Just exactly what fish see when looking at flies and lures is at the heart of a multi-billion dollar industry that sells gear to anglers who want to believe they just bought the hot color pattern that'll catch more fish.

But when it comes to figuring out what trout see when they look at the baits and lures tossed their way, science tells us no easy answers apply.

What a fish sees under water is as variable as the species of fish, the colors on the lure, the depth and clarity of the water, the time of day, the amount of light and even how old that trout or salmon is.

About the only thing anyone can say for sure is that fish don't see those lures in the same fashion the fisher does.

"It's neurologically impossible," says Keith Jones, a biologist specializing in fish senses and behavior at Pure Fishing, a company whose brands include industry giants Abu Garcia, Penn, Pflueger, Stren, Fenwick and Shakespeare.

"There's no way a fish can see what we see," Jones says. "We can't look through their eyes to see into their world. But we can kind of guess."

The guesses, however, are based on some solid science that starts with what researchers know about fish eyes, the light spectrum and what water does to light as it passes into the depths.

What appears as color is actually an object's ability to absorb and/or reflect various frequencies of light and how those frequencies cumulatively get processed by the brain through the eye.

A red lure, for instance, absorbs all the colors except red. Lures that reflect all the colors appear white, and those that absorb them all appear black.

Studies show fish possess many of the same rods and cones that denote colors for humans, but how they process that information can vary dramatically among the species, Jones says.

Most fish, such as bass, walleye and crappie, have receptors that allow them to see reds and greens, Jones says.

Members of the salmonid family (salmon, steelhead and trout) have receptors that not only detect more than the same red, green and blue bands in the spectrum seen by humans, they also possess receptors that expand their view into the ultraviolet spectrum invisible to humans, Jones says.

"We have really no idea what ultraviolet would look like," Jones says.

But trout and salmon tend to lose their capabilities to see ultraviolet light as they grow older, while fish like carp tend to retain that capability their entire lives, Jones says.

While humans eyes and fish eyes absorb the same colors, we vary greatly in our abilities to process what those colors mean.

"There are differences between our visual construction that create huge impacts in the differences we see," Jones says.

Human eyes are far sharper than fish eyes, and human brains are able to denote more subtleties in color variance than fish, Jones says. And they lack the capabilities to play favorites — no matter how many times a specific lure color seems to work.

"In most cases, when we come to the conclusion fish have favorite colors, it's based on pretty poor evidence," Jones says. "They don't have the neuro-system available to them to have those emotional attachments to colors."

It gets even more murky when you toss in the difference between how light acts in air and water.

Most air does not contain enough particles or other matter to absorb enough light to alter an item's color appearance. But that can differ greatly in water, which absorbs colors in descending order from reds to greens to blues as light penetrates the depths — until everything looks dark.

Colors last deeper in the water column in clear water like the open ocean, while turbid streams can gobble up color in more shallow depths.

"What looks red to us two feet away looks red to us 100 feet away," Jones says. "With fish, that's not the case."

When it comes down to it, fish see color more as contrast or as familiar patterns that might mimic their prey, Jones says. Sometimes the color contrast prevails in tickling that urge to bite; with others it's the suggestion of a pattern that reigns supreme.

"As anglers, we have to figure out what is most important to them that day," Jones says.

That's where Ramsey comes in.

Years of field tests and honing color schemes on lures has taught one of the Northwest's most famous anglers that it's up to the fish to decide what colored plug they want to bite.

Ramsey often fishes out of his boat with others present, and he likes to give steelhead or salmon a full palette to choose from, always changing plugs as he looks for the right combination.

"I change, change, change and let the fish tell me what they like," Ramsey says. "Don't tell them what they're supposed to like.

"All of us have changed color and got them," Ramsey says. "It's just hard figuring out what that right color is."

That's because there is no right color, Jones says.

A red plug looks red to a trout near the surface on a bright day in clear water, but it won't look the same in deep water at sunrise. The available light, water clarity, fish eyes and fish brains collectively contain so much variability that the right color one day can be the wrong color the next.

"You've got to get beyond that homo-centrism, where you think animals see things through the same type of eyes that we do, smell what we do, hear what we do," Jones says.

So why such detail in lures?

"Lures are first bought by anglers, and in a sense they are bought next by the fish," Jones says.

And you never know what conditions will create the right combination of color and contrast that makes a lure look like food at a given moment in a particular water body to a particular fish.

"It's because that color, given the prevailing background, has better contrast or the pattern imitates something it preys on," Jones says. "Other than that, I can't think of any other way color plays a role."

At Pure Fishing, Jones spends much of his time product testing. Much of his work lately has been on scents added to dough baits so widely popular among trout anglers in standing water.

To test scent, the dough baits all must be the same color to factor color out of the comparisons, Jones says.

For scent tests, Jones always uses chartreuse dough. And he always catches fish, regardless of what scent is used.

"We'd never say chartreuse is best," Jones says.

"But there is at least some truth to the idea that some things always work," Jones says. "And if you can reconcile that conflict, let me know."

Reach reporter Mark Freeman at 541-776-4470, or e-mail mfreeman@mailtribune.com.


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