August 10, 2006

By Bob Wattendorf
Florida Fish and Wildlife Commission

The best time to go freshwater fishing, for me, is whenever I get a chance. However, if your schedule is flexible, and you want to be a bit more scientific about it, pay attention to the moon. Many fish and game activity calendars you see in news media and elsewhere are based on the Solunar Theory, developed by John Alden Knight.

In 1926, Knight considered some folklore he picked up while fishing in Florida and decided to evaluate 33 factors that might influence fresh or saltwater fishes to be more active periodically. Three of them seemed to merit further examination -- sunrises/sunsets, moon phases and tides. From that, the avid fly fisherman created the Solunar Theory, which he named for Sol (the Roman sun god), and Luna (the Roman goddess who personified the moon).

Anglers already knew tides were an important factor in saltwater fishing success, and recognized the connection between tides and moon phases. Meanwhile, American Indians, and other groups that depended on hunting and fishing for survival, realized animals were more active during full and new moons. Knight speculated the relationship between the sun and moon, rather than tidal stages, might provide a way to predict fishing success. Knight determined that midway between when the moon rose and set, and vice-versa, fishing activity peaked. He coined the phrases “major Solunar periods” and “minor Solunar periods” to describe them. These periods of greatest animal activity (not only fish) last 90 minutes to three hours, depending on the moon’s relationship to the sun, its distance from Earth and the sun’s angle from the equator.

In 1936, Knight published the first Solunar Tables based on this information. However, we now know that, to be accurate, the precise times from each table must consider the geographic location and be adjusted for daylight saving time, when appropriate. You can approximate these times by adding six hours to the rise and set times for the moon (see an online calculator for any date and location).

The intensity of Solunar periods’ impact varies according to the position of the moon, its distance from Earth and the angle of the moon above or below the equator. New moons provide maximum impact when the sun and moon are traveling in rhythm with their forces combined. During a full moon, they are opposite one another, with one or the other nearly always above the horizon, and they provide a strong secondary peak.

Then the intensity tapers off to a minimum during the moon’s third quarter. June has the greatest combined Solunar influence. You should also consider local weather patterns. Fish and wildlife have an innate ability to predict weather and react accordingly. Barometric changes, especially a downward trend, often can turn fishing off. Conversely, sometimes an approaching cold front seems to make fish go into a feeding frenzy to beat the bad weather. Typically, if the barometer is steady or rising and the air temperature is significantly higher than the water temperature, a stronger response to the Solunar periods is likely, but immediately following a cold front, some fish are rather lethargic. Temperature is also associated with spawning times and can be a key factor in the seasonal patterns of fish behavior. You can find more about that - here.

A natural day for fish, and many other animal species, revolves around a twice-daily “biological clock” that appears to coincide with lunar time. It is based on the time it takes the moon to complete one rotation of the earth (an average of 24 hours and 53 minutes). This explains why ocean tides are about an hour later each day and why most fish, freshwater species included, will feed up to an hour later each day. Regardless of whether species are most active in daytime or night, sunrise and sunset are important to in their movements and feeding.

So when you put it all together, the odds are if you go fishing six hours after the moon rises or sets, and that time coincides with sunrise during a new moon, while the barometer is rising, the water levels are adequate, water quality is good, there are plenty of big hungry fish looking for food, and not too many big hungry mosquitoes, you’ve got the optimum fishing time. Or if all this confuses you as much as it does me, then remember . . . the BEST time to go fishin' . . . is whenever you can go safely!

Note: This article is derived from a variety of online sources including the Naval Observatory, solunar.com, primetimes.com and synsat.com.