Blame it on the sun. Blame it on the moon. Blame it on the weather, or blame it on George Ezra. We’ve all played the blame game after throwing the kitchen sink at those fish that won’t eat. No one wants to throw in the towel after the sink without having an excuse for trashing the kitchen.
Generations of anglers have invented reasons for coming home empty-handed. Mythology, folklore, lying, exaggeration, and fishing are synonymous. Can’t figure an excuse? Make one up, everyone else does. The moon is an easy target.
Some people claim that fishing when the moon’s phase is nearly full is futile because “the fish eat at night and aren’t hungry during the day.” Others claim that the best time of fishing each month is during the full moon and the three days on either side of it. The 2015 Farmer’s Almanac claims that the best fishing days are when the moon is halfway between the full moon and the new moon. That about sums it up. Many experts tend to agree that moon phase has a direct effect on fishing, but their theories and conclusions collide and contradict.
From my limited research, I tend to believe that moon phases affect fish, especially anadromous fish. The fish ladders on the lower Yuba River are monitored by cameras and sensors that track exactly when fish are using the ladder. I was surprised by the regularity of the fish movement as described by the waves on a season-long chart. There would be a bump in activity about every two weeks during the salmon migration. I overlaid the plot with a moon-phase chart, and blurring my eyes enough, I saw a rough correlation between the burst of fish movement and the moon phase. It wasn’t exact, but close enough to sell the idea with a clear conscience. The smaller of the monthly bumps was near the new moon, and the larger bump was on the full moon. These, of course were salmon that had recently entered fresh water after spending the previous years living in the ocean, and perhaps they were still in a “persistent activity rhythm” that kept them in synch with the tide cycle.
Fisheries biologist Ralph Manns has spent a lifetime studying bass and has kept detailed records of his catch, along with lunar positions. After 10,466 hours of fishing for bass (and catching 8,900 bass over a foot long) he concludes that everything else being equal, when the moon is directly overhead or underfoot (called a “major” period) and when the moon is 90 degrees from a latitude (known as a “minor” period), bass will be more active than during other periods.
The lunar effect is bolstered by the classic experiment in which oysters were harvested at New Haven, Connecticut, kept in the dark, and shipped to Dr. Frank Brown’s laboratory at Northwestern University, where they continued to open and close their shells with the rhythm of the tides. After a few weeks, however, the oysters were no longer in synch with the tides of New Haven, but instead in synch with what would be tides of Chicago. Did they feel the moon?
John Alden Knight, without a doubt, is the king of excuse making, and he made a pretty penny selling us an easy way to slink in the back door. He didn’t completely buy into lunar theory, and since it was already in the public domain, it wasn’t worth anything, so he created a marketable substitute.
In 1926 , Knight invented solunar theory.
He reputedly scoured his resources and found 33 different factors buried in local folklore that were used to explain both fishless days and outstanding days. He distilled those 33 factors down to three variables: The sun, the moon, and the tides. After some thought, he realized that tides are created largely by the moon, so he narrowed his theory to two causes, which were the relative position of the moon to the sun and the time of moonrise and moonset. It was angling astrology at its best, and the public ate it up.
Like fortune cookies and horoscopes, there are days when solunar tables are scarily accurate. Most of the time, however, they are no more predictive than a dart to a map. Solunar tables are ubiquitous. They come embedded in GPS software and are even posted at marinas. They are available for free on dozens of apps and are printed in every issue of the national bait-and-bullets publications. Run-of-the mill solunar tables have been replaced or augmented by such predictive magic as Astro Tables, also known as the Advanced Prediction System. Each author claims to have discovered the “real” relationship between the sun and moon and their influence on animal and even plant behavior.
Of course, when lunar, solunar or Astro Tables go astray, believers blame local phenomena such as boat traffic, turbidity, or changes in barometric pressure that mask the effect of the tables. A drop in barometric pressure is often cited as sudden death to a good bite. I have been there when it happens — and have been there, too, when the bite turns on as the weather grows bleak. Almost like clockwork, the barometric pressure drops in the early afternoon over Hebgen Lake in West Yellowstone, Montana. Huge cumulonimbus clouds boil into the sky, the sun is obscured, the wind shrieks, frequently it rains, and the bite turns on. The wind and the waves drive most fishing traffic off the water, but if you can deal with the lousy conditions, the best time on that lake is when the barometer crashes. But probably not because the barometer crashes.
Last August, in his excellent column at In-Fisherman.com, Ralph Manns flat-out states that “one of the most persistent myths in fishing is that barometric pressure controls the activity of bass and other game fish. Although many researchers have tried, scientific studies have been unable to demonstrate that such a relationship exists.” As anglers often see at Hebgen Lake, there a zillion variables (wind, clouds, turbidity, and so on) that typically accompany a drop in barometric pressure. No one has figured out how to eliminate all of the variables and pinpoint barometric pressure as the cause for any change in fish behavior. An extreme swing in atmospheric pressure such as might be felt during the landfall of a tropical depression is duplicated when the fish move vertically in the water column all of about 18 inches. Waves and boat wakes will create greater and more rapid changes in pressure than a fish will likely ever experience as the result of atmospheric changes. Turbulence in moving water certainly negates any discernible change in barometric pressure. Why won’t fish eat my fly? In my lifetime, certainly, we’ll never know for sure.
And that makes me happy.
