Does the moon play a role in catching more fish? Or is this a form of astrology for a fisherman? Anglers have varying opinions on this theory, ranging from only fishing on full/new moons to not giving the theory any thought. Whether you are a die-hard solunar fisherman or the ladder, it is interesting to know the history and evidence of this claim.
Solunar Theory and Moon Phases
Fishing using lunar location was first brought to the attention of modern fisherman after John Knight developed the solunar theory in 1936. The theory suggests there are precise times during the day when fish activity increase based on four lunar periods. These periods fall into two categories including major, and minor. Major periods last about two hours and are when the moon is straight overhead or straight below. Minor periods, which last about an hour, coincide with the rise and fall of the moon. John Knight also noticed that fish were more likely to be active under a full or new moon.
Mauri and the Maramataka
The Mauri people, indigenous to New Zealand used a lunar calendar to mark good fishing days from the bad. This calendar called the Maramataka translates to “turning the moon”. It follows the 29 days of the lunar cycle. The Mauri named each day and used symbols to indicate that a specific day would be good for fishing. They also kept track of days that would be good for hunting, harvesting and other activities. An example of one of these days is “Whiro”. This was the day of the new moon and was a day good for fishing with a line, or by torchlight. It is intriguing that a culture greatly connected to the environment used these methods.
Dr. Frank Brown
Using oysters, Dr. Frank Brown, test the idea of a connection between animals and moon phases. Oysters open their shells to feed during high tide, this made them the perfect species to test this idea. Dr. Brown had Chesapeake bay oysters shipped to his lab in Chicago. The first week of observing these mollusks showed they were opening their shells based on the Chesapeake bay tides. In the second week, however, the oysters started to change their behavior. They started to open at what would be high tide in Chicago (if Chicago had a high tide). This demonstrated that oysters open their shells due to gravitational force and not from other factors, such as water depth. Take into account that these are oysters and don’t exactly represent the hog of a brown trout you are trying to hook into.
It appears that the phases of the moon do play a role in fish behaviour and people have been exploiting this for hundreds of years. We can, at the very least, say that using the phases of the moon to improve the chance of catching fish is more than some astrological belief. There are, however, plenty of other factors that can affect fishing such as barometric pressure and overfishing. Whether you decide to adopt solunar theory or not, it is important to remember that there are no bad fishing days, just bad catching days.