Written Dec 14 2005

The Moon
Ever see those calendars with the fish symbols on them, supposedly indicating the days of the month when the fish bite best? Ever wonder where they come up with that? Take a close look at the best days and you will notice that they tend to occur at the same time as full and new moons. And this is no coincidence, as those who log atmospheric data in their catch records will notice that the phase of the moon can play an integral role in the success of the trip.

So powerful is this influence between moon and fish activity that it has been found that nearly two thirds of all IFGA record holding fish have been caught during full and new moon periods. Experienced fishermen know this and can be found out in force during these periods and it is why I include the current years' moon phases in the Reference section of this website and why I also record the moon phase in all my logs.

But why? What possible connection can that oversized, pock-marked rock in the sky have on the fish down here? The reasons are what we'll focus on in this article.

You usually only hear the term "astronomically high tide" when an ocean storm is due. However, the truth is we have astronomically high tides twice every month - you guessed it - during the full and new moon phases. In fact, the whole reason we have tides in the first place is because of the moon. You see, although earth is much larger and has the far greater gravitational pull (keeping the moon where it is), the moon also has it's own gravitational pull on the earth and results in the constant raising and lowering of water levels depending upon the part of the earth that faces the moon. The part of the earth facing the moon (as well as exact opposite location facing away from the moon) experience simultaneous high tides, and the parts of the earth at right angles to the moon experience simultaneous low tides. Because it takes the moon 12 hours and 25 minutes to move from overhead one location on earth to a position on the opposite side, we experience a high tide at that frequency. The halfway point (6 hours and 12.5 minutes) is when we experience low tide. When the sun gets involved and becomes in the same line as the moon with the earth in the middle (full phase) or opposite when the moon moon is not blocked by the earth (new phase), the increased gravitational pull from the sun gives us astronomically high tides.

Increased Feeding Activity
While all this talk of the moon phases and tidal flow may be interesting, I realize they don't answer the critical question of why any of it matters to the fish. Theories abound, but there is no question that this stronger gravitational pull results in increased feeding activity among all fish. When considering saltwater, it is easier to understand as the stronger tides create stronger currents which push baitfish around and make it tougher for them to fight the current and stay put in safe locations away from predators. In freshwater, it appears to influence insect activity, although no one knows why for sure. One theory I heard years back was one called the "Predator Overload Principle." This theory stated that during periods of high water, larger spawning fish would seek out shallow areas to deposit their eggs and for the next two weeks (as the tides were much lower) predator fish would not be able to consume either eggs or hatchlings because the water would be to shallow. This ensured such a large hatch, that when the water became deep enough to enter, the predator fish would be faced with such numbers of prey that they couldn't possibly devour them all. Interesting theory, but again doesn't explain why freshwater is affected as well.

So, what's this all mean? Well, for me, I would recommend trying to schedule your fishing times during full and new moon periods. Note the conditions (sunlight, temperature, barometer, etc.) and on the days when conditions are fairly equal but the moon phases is opposite, log your success. If you come to the same conclusions as millions of angers already have, you will have added another weapon to your arsenal and become an even better fisherman for it.

Below here you will find a picture I made to illustrate how the phases occur. Notice the position of the sun, earth, and moon. The outer ring of moons shows you the orbit of the moon and how at full phase the lit side is in front for everyone to see (remember, the earth rotates completely in 24 hours), and at the new moon phase, the dark side of the moon is in front for eveyone to see. The inner ring shows you how the moon appears to us in the sky. After a full moon (heading up) the moon wanes until it is invisible and then a "new" moon occurs and waxes (heading down) until it is full again. The halfway points are called quarter moons, because we are actually only seeing one quarter of the entire moon. The top most moon in my illustration is considered the "last" quarter and the moon at the bottom of the illustration is considered the "first" quarter. Moons that show greater than half of a circle are called gibbous moons and moons that show less than half of a circle are called crescent moons. It takes approximately 29-1/2 days to complete the cycle from new moon to the next new moon.

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