By Bill Divens | 12/20/2010
Having spent countless days guiding Northern California and Southern Oregon rivers, I’ve discovered that underwater visibility of bait is one key ingredient to catching more salmon. Employing simple optical concepts puts more salmon in the box. While we’ll only be scratching the surface on this topic, let’s start our exploration of the underwater world of color with a simple child’s question:
Daddy, why is ocean blue?
This dreaded question has confounded parents since the beginning of time. So, once and for all, here is the incredibly simple answer that will make Junior believe, at least temporarily, that you are a genius. The ocean is blue because water is blue. It’s that simple. Water looks clear when you look through a water bottle or in the bath tub, but with a few yards of water between you and the light source, water takes on a distinct blue appearance. For the very geeky among us, the reason is overtone vibrations of O-H bonds in liquid H2O extending well into the visible region.
The take away here is that the deeper we go in the water column, the less light there is and more importantly, the color of the light changes. Specifically, colors disappear in the following order – red, orange, yellow, green and at much greater depths blue. That’s why even on a cloudy day with an all white sky, pictures shot deep underwater appear blue.
But I Don’t Fish in the Deep Blue Ocean
For salmon anglers, even less light penetrates the water column. Near shore, in estuaries, and rivers, suspended particles scatter and absorb first UV followed by violet, indigo and eventually blue light, leaving the dominant colors of blues, greens and yellows depending on the density of the particles* as shown in the upper curve coastal average in Figure 1.
Figure – Water light absorption per meter by color.**
As an angler you ask, what does this mean to me? First of all, I just saved you a bunch of money. As we see from Figure 1, near UV light penetrates quite well in the clean deep ocean. Not so much in salmon water where there are lots more particles and organic materials that absorb UV. So, dumping your current inventory of salmon lures and roe cures and replacing them with UV is probably a waste of money. With all that money you just saved, you can now buy a blue flashlight so that you can test your lures for something that is really important – fluorescence.
Before we can move on to practical salmon catching tips, we need to have one more geeky discussion about a phenomenon known as fluorescence. Fluorescent paints and dyes absorb light of shorter wavelength (left side of Figure 1) and emit light of longer wavelengths. For example, if you shine a blue and/or green light on a fluorescent red lure, it will glow red even if there is no red light shining on the lure. Likewise, if you illuminate a fluorescent blue lure with violet or UV light, it will glow blue and if you shine a blue light on a fluorescent green lure, it will glow green.
The farther you move to the right of the chart, the more important fluorescence becomes. Why? There is just not that much red or orange that penetrates the water column. At more than 5 ft. deep, non-fluorescent red begins to fade out to a dark grey. Go to 10 ft. and orange starts to wash out.
What about green and blue green lures – do they need to be fluorescent? Yes they do because a significant amount of blue, indigo and violet penetrate to our typical 6 – 40 ft. salmon fishing depths. For example, a fluorescent green lure will gather blue, indigo and violet light and emit green light making your lure brighter than the background. From a visibility standpoint, you now have a double winner – the green lure is reflecting ambient green light in the water as well as glowing green from fluorescence.
So, now that we all have a better understanding of underwater light transmission, let’s move on to some familiar salmon lures and check out why they work so well at least from a visibility standpoint.
Figure – Kwikfish wrapped with Pautzke’s Red Nectar soaked sardine fillets shot in room light.
Figure – Same Kwikfish shot in blue (underwater) light showing fluorescent lure colors and
fluorescent red Pautzke’s Nectar soaked sardine fillets.
Chartreuse (yellowish green) and silver Flatfish or Kwikfish
With the possible exception of well cured roe, this plug accounts for more river Chinook bonkings than any other bait. Refer to Figure 3 and you can see why. Illuminated with 470 nm. Blue light, both the plug on the right and in the middle glow a bright greenish yellow. Note that the chartreuse appears brighter at depth while the silver starts to turn dull. Here we see the “double visibility win” – the chartreuse will reflect yellow green light transmitted through river water and absorb shorter wavelengths, also transmitted through river water, and glow a greenish yellow.
Can we improve on what is arguably a perfect river salmon lure? YES! Check out the sardine wraps on the Kwikfish. While regular sardine fillets are non-fluorescent, these fillets have been soaked overnight in Pautzke’s Red Nectar with a little salt added to help fix the color and firm the fillets. Not only does Pautzke’s Nectar add the smell of salmon roe to our plug, it also makes it more visible. Available in fluorescent blue, yellow, orange and red, Pautzke’s Nectar soaked sardine fillets are a great way to add color to your plugs without painting them permanently.
Figure – Anchovy soaked in Pautzke’s Blue Nectar
Guide Green Blades
In the Rogue Estuary, most Chinooks are taken on spinning anchovies. Many anglers add a few beads and a #4 spinner blade ahead of the anchovy. The most popular blade is “green on green”. And…you guessed it without even seeing a picture. The best blades and beads are highly fluorescent just like the Kwikfish. But, can we improve on this perfection too? Again the answer is yes. I actually stumbled on this little trick while targeting silvers in the Rogue Estuary. As we all know, silvers are absolute suckers for roe. So, I grabbed the only Pautzke’s Nectar I had with me that day – blue and a little salt and soaked my anchovies overnight in the mix hoping the roe scent would attract silvers. The result is shown in Figure 4. While I didn’t see a marked improvement in my silver catch (silvers seem to like fluorescent reds and oranges much better), my catch rate on Chinooks improved substantially. Anchovies soaked in Pautzke’s Blue Nectar are now my go to bait on the estuary.
Cured Roe, Jar Salmon Eggs, & Fire Corn
We don’t even need a picture for this one. The standard pink, orange and red dyes found in Pautzke’s Fire Cure are all highly fluorescent which when added to the scent makes Fire Cure such a deadly egg cure. Ditto for Balls ‘O Fire salmon eggs and Fire Corn.
Much of the time, our salmon baits are wiggling around in deeper stained or colored water. Even seemingly clear rivers absorb and disperse much of the light. Add to the equation cloudy days, mountains and trees shading the river and morning and late afternoon fishing and we can see why, in most cases, we want our offerings to shout out “Bite Me”. If they don’t, the salmon will never notice them.
There are other situations where we need to be subtle. Take for example a shallow pool of gin clear water on a bright sunny day. You might get bit on a big bright chartreuse lure, but the more likely outcome would be salmon moving away from your offering. A better strategy would be to take all of the above and do just the opposite. Smaller metallic (gold, silver, copper) lures, roe cured in Pautzke’s Natural Fire Cure, plain anchovies, or baits soaked in Pautzke’s Purple Nectar that doesn’t fluoresce much, but rather, reflects ambient blue and red light would all be great choices.
Figure – Pautzke’s Nectar shot in room light like you would see them in the store.
Figure – Pautzke’s Nectar shot with only blue light. Notice that the Chartreuse, Orange and Red all fluoresce while the blue reflects some blue and fluoresces a little blue green. All good, high visibility choices. If these bottles were not fluorescent, only the blue would reflect the blue light and the others would appear black.
Don’t Believe the Label
Many lures or baits are advertised as fluorescent, but only fluoresce weakly while most lures and cures don’t even tell you whether or not they are fluorescent. So, how can you tell? Buy a blue LED flashlight and take it shopping with you. While not exactly the color of every water condition, it will give you a good idea of whether or not your new lure fluoresces underwater or not. If you fish the deep blue ocean or particularly clear inland lakes, invest in a near UV flashlight (Google “395 nm led flashlight”) to test the fluorescence of your blue lure.
Color is only one of many dimensions of getting a salmon to bite. Vibration, color, movement in the water all come into play, but getting your offering noticed will certainly put more salmon in the box.
For more info on Divens and his guide services in Southern Oregon and Northern California, please visit www.salmonkinglodge.com
*This is a highly simplified explanation of “why is the ocean blue”. If you really want to dig into this subject, read Why is Water Blue by Charles L. Braun and Sergei N. Smirnov. For more in-depth information on underwater optics and an exhaustive discussion of how lure color applies to steelhead fishing, read Dr. Colin Kageyama’s excellent book What Fish See available from Amazon.com. And…the answer to the other dreaded question “why is the sky blue?” is “Rayleigh Scattering”.
**This chart comes from a great article on underwater photography – http://www.seafriends.org.nz/phgraph/water.htm