Moon Cycles and Fish Behaviour by Neil Grose

The Moon and its phases would have to be one of the most significant forces on the planet.

Apart from making the tide go in and out, it is reputed to have many different effects on man and beast alike. The term lunatic is derived from the behaviour of people who appeared deranged on a full Moon - some anglers also appear deranged with their fishing as well!

So I guess it isn't too much of a jump to study fish's behaviour in relation to Moon cycles. Behaviour of saltwater species and tidal movement is linked - this is one of those undisputable facts of fishing (and there aren't many of those), but how do the different phases of the Moon effect fish behaviour in both fresh and salt water?

There are many coastal cultures around the world that predict fishing success or failure according to Moon and Sun cycles, and indeed here in Australia we have a published predictor, the Anglers Almanac (published by The Great Outdoors Publications Pty Ltd). But what are the principles behind it, what real application does it have, and the big question, do they work?

MOON AND SUN CYCLES

Before we head off into the major questions surrounding fishing activity and the Moon, we probably should take a little time to explain how the Moon affects the tide. The Moon orbits the Earth, and the Earth orbits the Sun. The Earth spins as well while it orbits the Sun, one rotation of the Earth is a calendar day, and one orbit of the Earth around the Sun is a calendar year.

Both the Moon and the Sun have a gravitational influence on the Earth, which is reflected in the tides. It is primarily the gravitational pull of the Moon that makes the tide go in and out - it pulls the water towards it.

As the Moon moves around the Earth the force of the pull moves with it as well; this is why tides run in and out.

The Sun also has a significant influence as well. When the Sun, the Moon and the Earth are in alignment we see the most gravitational pull on the tides. These are termed spring tides, which feature the highest of the high tides, and the lowest of the low tides. When the Moon and the Sun are at opposite angles, we see the least influence on the tides, called neap tides. These see the lowest of high tides and the highest of low tides. Each has their advantages and disadvantages when it comes to fishing.

There are 8 phases of the Moon: