Many fishing enthusiasts regard the use of green light for night fishing with a certain amount of disdain and believe that green lights are simply a marketing ploy. An analysis of scientific papers from universities around the world, however, provides conclusive data that green light is the best compromise for night fishing.
It's not hype and it's not a gimmick to sell lights. It's real, even though few folks have actually done the homework to understand the mechanics of the situation. At best, they have simply placed different colored lights in the water and observed which lights had the most "customers", i.e. bait fish coming by.
The ultimate goal of any fishing endeavor is to catch fish. In order to do this, we need to attract the fish by appealing to their senses. The primary lure is something that looks like food to the fish, thus they must be able to see it. In the daytime, this is easy. The sun provides broad spectrum illumination. The fish see the bait, and if they are feeding, they take the bait, and the hook.
At night we must provide the light. Bright, white sunlight works in the day, and so do bright, white, high-power spotlights hooked up to generators at night. It's simple and effective, but it's noisy, somewhat dangerous, and big lights attract lots of bugs. To diminish the bug problem, submerge the light. This is fine with safe, low-voltage methods, but can be deadly to submerge a 110 VAC light. A low-voltage system is much safer. Incandescent lights provide a broad spectrum of light but are inefficient compared to fluorescent lights.
Although fluorescent lights require high voltages, if only low voltage is sent to the submerged light assembly, the necessary high voltage can be generated inside a water-tight housing. Should the housing leak, the inverter circuitry that provides the high voltage will simply fail without becoming an electrical hazard. With LEDs (Light-Emitting Diodes), it is all low voltage and extremely effective and safe.
The use of white light from any source assumes that a broad-spectrum light propagates well in water. It doesn't. Pure water looks blue and it passes blue and green light with very little absorption. Typical lake, bay or offshore water is not pure, but contains various dissolved organic matter, photo-synthetic pigments and particulate material. Salt has very little effect on light absorption, but the other ingredients do. Tests reveal that light between 450 and 550 nm (nano meters) transmits through lake, bay or offshore water with the least attenuation. Other wavelengths of light, especially near the low, infra-red end, are dramatically absorbed.
Green light has a wavelength around 525 nm, near the center of the range, thus green light propagates better than other colors in fresh or salt water. Rather than waste energy by using broad-spectrum white light, use green light.
Human eyes and fish eyes respond to similar colors through the use of short, medium and long-wavelength receptors. While human eyes are less sensitive at 500 nm, fish eyes are very responsive throughout the region between 450 and 550 nm. In fact, two of the three to four sets of typical fish-eye receptors (the number of sets depends on the species), are very responsive to the wavelength of green light. Note that this is also the primary portion of the optical spectra that travels well in water.
A low-power, low-voltage, low-cost, high-intensity, submerged green light is the BEST solution for night fishing. Current technology dictates that a large (24" or longer), green, Light-Emitting Diodes (LEDs) in a water-tight, clear, non-metallic housing should be suspended under water for optimum results. LEDs are more efficient and more rugged than incandescent or fluorescent lights.
Want to research further? Go to Google and search on topics associated with light spectra absorption in water, animal sensor spectral sensitivity, light-absorbing components of the aquatic system, visual ecology of fish, etc. Technical papers from such diverse locations as The School of Biological Sciences at The University of Sussex in England, The University of Queensland in Australia, the Department of Marine Sciences at The University of Southern Mississippi and Fiskeriverket in Sweden, will turn up.
All the Best, and Great Night Fishing!
Andy MacAllister CEO - The Fishinglights Company, LLC