The Science Line: The Mysteries of the Moon

By Jake Bussolini

More than ten years ago I began writing about the myths being used to blame or credit the sun and moon for creating good or bad fishing days. Nearly every outdoor magazine contains sol-lunar tables that tell anglers the exact month, day and time that will produce the best fishing.

I have never argued that the tidal changes created by the gravitational forces influenced by the Moon actually do have a significant influence on fish behavior for ocean living fish. I have taken a strong position however, that I could find no scientific proof that Moon phase has any effect at all on fresh water fish behavior. With the absence of solid science, like other curious people I looked to my years of data to support my theory and I was mildly convinced to continue to maintain my position.

I tested my theory against published tables for several years of fish catches. Of course I could use only that data that was recorded during long days and nights when the fishing times coincided with times listed in the published tables. I found ten good periods covering a span of five years where my total fish catch was more than 700 fish, mostly bass. The results of the daytime comparisons are shown below. The correlation with the published tables for the daytime fishing was only 21.7%. I ran the same comparisons for night fishing and my correlation with published tables was only 18.2%. Neither of these results gave me much confidence toward the accuracy of the published tables.

There have been others who have made similar experiments and their results have been similar to mine. One such angler is Joe Butcher who has published extensively on this subject. Butcher recently changed his mind about the moon, indicating that he had re-examined his data and found a direct correlation between Sun up and Sun down and Moon up and Moon down. He has not taken a strong position on the up-down theory, but he has gotten excited by the idea that there is a period of 5 days after a full Moon when fishing definitely gets better, at least in terms of bigger fish being caught during these periods.

Butcher however leaves the door open for other ideas since he also believes that the effectiveness of the full Moon theory is greatly influenced by the unpredictable local weather. Does this mean that we now have to look ahead weeks or even months to pick the good fishing days and assume that during these days the weather will be clear with no clouds, rain or overcast skies? If so I say not so fast.

Several professional bass fishermen have be asked about the Sun/Moon theory and they all seem to imply that they make note of the Moons position but they don’t use it for planning their fishing activities.

I have taken a rather strong position about the Sun’s effect on fish behavior since there is little argument that clear skies and bright Sun normally make for bad fishing days, or at least give anglers cause to change their fishing techniques during these times. But the Moon, I still need to find some legitimate science to change my mind. I will bend a little and start collecting data after full Moons, but until I find convincing results, I’m going to stay away from those tables that tell me exactly when I should expect to catch the big monsters.

Jake Bussolini is a freelance writer who has written nine books about fresh water fishing. His books can be examined at www.booksbyjake.com.