Fish Vision and Lure Decision by Noah Bressman
We have all been at a tackle shop, browsing aisle after aisle looking for the perfect color of lure, taking way too much time to decide which shade of green soft plastic you want or which hard bait looks most realistic. While we consider what we think would look most appetizing to a fish when making lure decisions, we rarely consider how the fish see our lures. What do fish actually see? To answer this question, we first have to analyze the medium they live in: water. According to Dr. Eleanor Caves, an aquatic visual ecologist at Duke University, “water is a highly attenuating medium compared to air, [meaning] fine details disappear over relatively short distances in water… and colors can become muted or not visible at all through some water types.” While in air, you may be able to see something clearly from a distance, but underwater, many of the details are lost at the same distance. Additionally, the visual acuity of fish is much poorer than our own (vision is actually one of the only senses that us humans are good at compared to other animals), so they cannot see details as well as us, regardless of the medium. Using a program called AcuityVision, Dr. Caves takes images of objects underwater (below left; original image by Jason Arnold / jasonarnoldphoto.com), like a lure, and using information on a fish’s visual acuity from her review paper on the subject (Caves et al., 2017), she can create an image from a fish’s point of view (below right, in this case, the visual acuity of largemouth bass, Micropterus salmoides, is used). While the overall shape and some of the patterns are still visible, a lot of the fine details of the lure is gone. Therefore, when you’re considering spending extra money on finely-detailed, hand-painted lures, it’s worth considering whether fish can actually see those details.
Water also affects how fish see colors. Even under crystal clear water conditions, colors disappear with depth and distance. Wavelengths of light like red and orange disappear relatively quickly with depth, no longer visible at just tens of feet. A red lure won’t be invisible at one hundred feet down, but it’s like printing a color image in black-and-white: it’ll look like a shade of gray. However, other colors like green and blue are still visible a couple hundred feet down. If you are fishing in deep water, you’re likely better off using blue lures, or focusing on the pattern, shape, or movement of your lure rather than on the colors. Additionally, water conditions affect how colors appear to fish. Compared to clear water, colors do not penetrate as much in muddy and murky water. Dark colors tend to work best under these conditions because they have high contrast to the water, and black will still look black even if all of the color disappears. However, there is a bright color that I’ve had fantastic luck in murky water with recently: chartreuse.
Chartreuse is a bright, neon yellow that is common in soft plastics. However, according to Dr. Becky Fuller, professor of animal biology of the University of Illinois at Urbana-Champaign, it does not appear yellow to most fish; chartreuse actually appears bright white to bass and most other fishes because they are dichromatic, meaning they have two types of cone cells (the cells that allow color vision) in their eyes. They cannot discriminate between as many colors as we can (humans are trichromatic, and have three cone cells), so bass are color blind, just like your dog. Many other predatory fishes are dichromatic, but many coral reef fishes have 3-5 cone cells. This allows them to see even more colors than we can (ones you can’t even imagine!), which is likely helpful in there very colorful environment. Compared to humans, the cone type that bass lack aborbs yellow light, which is why they see chartreuse as bright white. Dr. Fuller has developed an app on the iOS store called BassVision, which allows you to see what your lures would look like to bass underwater under different water conditions. Under the “human” view in the app, the lure below (left) appears chartreuse, but under bass view, the lure is just white (right). This isn’t the crazy part about chartreuse, though; according to Dr. Fuller, it glows underwater! Or at least it appears to glow. Like a neon shirt under blacklight, chartreuse lures are fluorescent, meaning that they absorb light at a lower wavelength (like UV or blue light), and emit it at a higher wavelength (like yellow). Since bass can’t see yellow, a chartreuse lure would appear bright white to them, even brighter than the background because of the fluorescence. Since this color “glows”, chartreuse lures works well in murky water, more so than other bright colors that are not fluorescent.
So, is it worth spending more on nicer lures or spending a lot of time picking out the perfect color? Bass won’t be able to seen fine details, at least not until they are right next to the lure, so it may not be worth spending a lot more on the most realistic-looking lures (often lures are meant to catch fishermen more than the fish). However, the way the lure moves and rattles, how deep it dives, how durable it is, etc., do matter, so these may be more important to consider when choosing your lure. Colors can make a difference, but a fish won’t see your lure the same way you see it. The overall color matters more so than the exact shade of color, so don’t worry if the tackle shop is out of your favorite color of Gary Yamamoto Kreature (green pumpkin with black glitter), the watermelon with black and red glitter works just as great (at least in my experience).
Caves, E. M., Sutton, T. T., & Johnsen, S. (2017). Visual acuity in ray-finned fishes correlates with eye size and habitat. Journal of Experimental Biology, jeb-151183.
Noah Bressman is a PhD candidate studying fish biology, functional morphology, and biomechanics at Wake Forest University. Below is Noah with a Skipjack Tuna (Katsuwonus pelamis), caught south of Long Island, NY on a big, white streamer.