The GRAIL mission determined the internal structure of the Moon in great detail for nine months during 2012. Armed with this the new information, GRAIL astronomers were able to redefine the sizes of the largest impact basins on the lunar surface.
This cycle has been appropriately named the 'dark moon'. The cycle from one dark moon to the next is called a lunation and an average lunation calculates at about 29 days, 12 hours, 44 minutes and 3 seconds (roughly) To be fair, it does deviate in relation to the moons erratic orbit patterns and is affected by the gravity conflict between the sun and the moon.
The bottom line is that these two forces of Mother Nature have an amazing impact on the feeding activity of fish and using this information to your advantage will make you a more successful angler. Take a few minutes and learn some of the simple rules relating to the weather, the moon, and fishing as soon as you can if you want to catch more and bigger fish.