The colors on the chart are:
Dark blue - night
Light Blue: dusk and dawn
Yellow: daylight
the colors at the bottom of the chart are described below.

There is a thing called the Maori Fishing Calendar. The Maori are the aboriginal tribe that inhabits New Zealand. The Maori (and many other Pacific peoples) found that on certain days of the lunar cycle, fishing was better than at other times. In the illustration above, the graph shows that the best time to catch fish is from 12 P.M. to 2 P.M. There are smaller peaks at around 6:45 A.M. and 7:30 P.M. If you only have an couple of hours to spend, you may prefer to go out at noon rather than nine or ten in the morning.

Does this stuff really work? I wouldn't swear by it... Or plan on catching my meals by it... There are, after all, still the effects of weather and season to be factored in. However, many people are quite convinced that, on balance, you will catch more "fish per unit effort" on a day when the Maori calendar predicts good fishing than on other days.

The moon's gravitational pull is said to directly affect animal appetites. When the moon is overhead, for some reason, it makes fish hungry. When the moon is underfoot, it also seems to make fish hungry. This is true for both fresh and salt water fish. The gravitational pull of the sun must have a similar, if lesser effect. So, when the sun and the moon are 'up' or 'down' at roughly the same time - as happens near new and full moon - fishing should be the most productive. Some people say the hour around moonrise and moonset have a similar, if lesser effect.