Man has long understood that there is a relationship between the cycles of the moon
and the activities of fish and wildlife. The earliest fishermen used the lunar affected tides
to determine when and where to cast their nets. These conditions spawned much lore
and many superstitions among our ancestors.
“I believe that the moon, and its effect on wildlife, has a tradition that is basically
timeless,” explained Doug Hannon, featured on television as ESPN’s Bass Professor.
“The more hocus pocus there is around something, and the more legend and lore there
is around something, generally the truer it is. That doesn’t mean the lore is true, it
means that the effect is true.”
Today, scientists understand that the moon affects the earth in dramatic ways. The
gravitational pull on the surface of the earth even creates earth tides, a slight movement
in the crust of the earth that has been associated with volcanic eruptions and the
movement of tectonic plates that cause earthquakes.
And during this century, sporting anglers have increasingly used the moon’s daily
movement in the sky and its monthly phases to determine when their best opportunity
for success might occur.
In 1926, John Alden Knight considered local folklore about the moon that he had grown
up around in his native Florida, as part of a study of 33 factors that affected fishing. As he
proceeded, three factors seemed to merit special attention: the sun, the moon and the
He gathered information on 200 incidents of large numbers of fish caught and individual
record fish. A pattern emerged wherein 90 percent of those fish were caught on a new
moon. Also, a pattern indicated that these fish were caught in greater numbers based
on the moon’s position throughout the day relative to where it was in its monthly orbit
around the earth – fish fed more actively during different times of the day based on which
phase the moon was in.
Alden established major periods of feeding activity based on his data, and eventually
intermediate periods of activity that were less dramatic and shorter in length were
discovered between each of these major periods.
In 1936, Alden published his first solunar calendar with the major and minor periods
stated for each day of the year. Solunar tables are still valuable tools used by anglers
Study in the field
Hannon, a diver, has spent hundreds of hours beneath the surface studying largemouth
bass behavior. As a life-long angler he reports catching more than 800 bass of 10
pounds or more and his meticulous record keeping amounts to one of the most
extensive ever field studies on bass behavior.
“I started studying it many, many years ago by just keeping records on times that I
caught fish and times that I didn’t, and I was really quite surprised at how much effect
the moon actually had,” Hannon said. “I can tell you that the reaction is extreme and the
bigger the fish, the more extreme it is.”
Hannon believes larger fish have a tendency to be more regimented in their activities
and are better able to take advantage of a given opportunity.
Like the rest of the fisheries community, Hannon still has only theories as to exactly why
fish react the way they do. Part of that answer, he believes, is simply a matter of timing.
“All of nature has to have a clock, a cycle around which to organize its activities. Fish
spawn at particular moon phases. The fact that they all do that at the same time and in
the same places gives them the ability to get together and do it successfully, all at one
time, and overload the predators so that the young have a greater chance of surviving.”
Hannon does believe that the gravitational pull of the moon has an effect. It may not be
as much of a physiological effect on the bass itself as much as an effect on the baitfish it
“You have to understand that it doesn’t have to affect everything. If (fish) are keyed to
something that it does affect like minnows or insects or plankton movement, which also
cycles and gathers near the surface during particular lunar periods, then they are keyed
to the moon. If a person wasn’t tuning his activities to a fish that is affected by the moon,
then he probably wouldn’t be. But if he is keyed into fish that are reacting to it, in essence
he is affected by it.
“How much is due to activity cycles that occur in the water rather than the moon itself, I
don’t know. But the fact is the fish do react.”
Over the period of a month, the moon changes its relative position to the sun, Hannon
explains. A new moon, for instance, is in front of the sun with the sun shining on the
back side of it. They are basically on the same side of the earth. A full moon is when it is
on the opposite side of the earth from the sun. In both the new and the full moon, the
effect of the gravitational pull of the moon is combined with that of the sun, and the
gravitational effect on the earth is greatest. The effect is approximately the same in
regards to what it does to tides. It’s that alignment that produces the most gravitational
The elliptical orbit of the moon also means that the moon is closer to the earth at some
times more than others. At its closest point, the moon is in perigee. Apogee is the term
for the moon at its farthest point from the earth
“When it is in perigee, there is a greater tidal effect,” Hannon said. “When that
corresponds with a new moon or a full moon, you have the most extreme tides and the
most extreme effect on wildlife.”
Though such events as the “Muskie Rampage” on Minnesota’s Leech Lake in 1955,
when huge numbers of fish were caught, have been associated with the moon in
perigee, Hannon believes that it is the daily major and minor fishing periods that anglers
should pay heed to.
“A major period is when the moon is either straight up or straight down,” Hannon
explained. “Of course it is not straight above us; it goes in transit to the south in this
hemisphere, but it is as high in the sky as it is going to get. Or it is as low in the sky as it
is going to get.”
That lowest point is when the moon is on the opposite side of the earth.
“The gravitational effect on the earth is precisely the same in both cases,” Hannon said.
“In both cases you have high tide, other things being equal.”
A high moon exerts the greatest amount of gravitational force on a given part of the earth,
while a moon on the far side of earth creates the least amount. Due to the centrifugal
force created by the spinning of the earth, a force which pushes away from the earth’s
core, a lack of gravity on the opposite side of the moon creates a “bump” on both sides
of the earth.
“You would think that when the moon is down it would pull the water down, but what
happens is there is less gravity on that side of the earth. The water on the far side of
earth from the moon humps up simply because it doesn’t weigh as much.”
During a full moon and the new moon, the major period occurs in the middle of the day.
“People think that is strange until you ask them … everybody remembers the biggest
fish they ever caught in their life, most of them will say, ‘You know, the funny thing is that I
caught it at two in the afternoon.’”
Remember that a good nighttime trip begins with adequate planning and preparation.