Friday, October 15, 2010
Dr. Jones Discusses Bass Blues
If you're fishing a jig, chances are it's either green-pumpkin or black/blue. Okay, we'll add brown/purple for California and Ozarks anglers.
Black/blue is one of the best jig and trailer colors of all-time, but research suggests a better description might be black/gray.
The combination of black and blue is deadly on a jig, and black/blue-flake is one of the most popular big-worm colors.
What's mysterious, though, is that bass might not even be able to distinguish the blue tints.
Berkley director of research Dr. Keith Jones, in his book Knowing Bass, devotes an expansive chapter to bass vision, with a lengthy section on color perception.
There's anecdotal evidence that suggest color is critical in bass fishing: Your buddy's whacking them, but you can't buy a bite. He hands you the color he's throwing and right away you're getting hookups.
But a scan of tour-level winning patterns over the past decade shows that pros throw only a few different colors – green-pumpkin, watermelon, black/blue, junebug, plus naturals (often with chartreuse tints).
So how much does color really matter? It matters a lot to the tackle retailer and manufacturer. More color options equals greater sales. And it matters to us as fishermen, because color has everything to do with confidence.
But according to Dr. Jones, some colors matter much more to bass because they might only be able to discern a certain spectrum of colors.
Rods, Cones and RGB
Color perception varies greatly in fish, Jones writes. Fish, like humans, have a series of rods and cones in their eyes that undergo reactions to light and allow the brain to build a picture of what's "seen." Cones control color perception and the human eye can discern millions of different colors based on three primary colors – red, green and blue (or RGB, like in televisions and computer monitors).
Biologists believe that an animal must have at least two of the three (RGB) cone cell-types to see color, Jones writes. Some oceanic fish that inhabit clear water have all three types. Carp, goldfish and minnows actually have four – the extra allows them to see ultraviolet light.
Jones notes that no direct reports exist that measure the specific types of cones bass possess, but it's believed they have two – red and green. Bluegills, a species closely related to bass, are known to only have red and green.
The absence of blue cone pigments has been shown through experiments, Jones argues. One study by Dr. Don McCoy of the University of Kentucky showed that bass can be trained to distinguish all colors between red and blue. However, they learned to distinguish colors in the red and green sectors quite quickly, but struggled to differentiate shades of blue.
Earlier work by Frank Brown at the University of Illinois drew a parallel conclusion.
"This suggests that bass color vision is relatively good from red to green, but weak in the blues and violets," Jones writes. "Bass often confused dark shades of blue and purple with heavy shades of gray, or in the case of very intense colors, with black. As the spectrum reaches a point in its shift from green to blue, bass's color vision seems to fade out entirely. Beyond this point, blues and purples, and to some extent dark shades of green and brown, are interpreted by bass simply as "dark." Very strong shades of red have the same effect."
To put it differently, based on research, a black/blue or black/purple bait might be seen by bass as simply black/gray, or dark/semi-dark. Conversely, a bass might be able to see a color like watermelon/red-flake more as humans see it.
There are plenty of gray hardbaits, but no gray softbaits come to mind. Maybe that's the next frontier of color development for bass – more a lack of color with an emphasis on grayscale color change. Then again, maybes the grays are already covered by current blue and purple color combinations.
> Knowing Bass: The Scientific Approach to Catching More Fish by Dr. Keith Jones is available from The Lyons Press.
> Some readers might be confused, since they were taught in art class that the primary colors are red, blue and yellow. That's true when using pigments, like paints in art class. It's called subtractive primaries – when you blend the three primary colors you get black, or the absence of color. But when dealing with light, and an animal's perception of light, red, green and blue are the primaries. It's called additive primaries because when you blend all three you get white (the presence of all colors). This article deals with light perception, thus the relevant primaries are red, green and blue.
In a research environment, bass displayed a strong ability to discern colors in the red and green spectrum (top, middle), but difficulty discerning colors in the blue spectrum (bottom).