By Rusty Chinnis
special to the sun

The early morning light played over the bare flats, exposing sand bars, potholes, channels and grass beds that had been covered with water an hour before. As my tide chart had predicted, the water was just beginning to rise as I anchored the boat and began wading the edge of a channel that led onto the flat. I worked my way up as the tide rose, taking snook, trout and ladyfish on almost every cast. On a different day I would remember these contours and target the fish as they dropped with the tide into these same channels and potholes.

Most anglers have a general understanding of tides. They know that they fluctuate approximately one hour every day and that there are often four tides a day, two low tides and two high tides. Anglers are also aware that there may be only one tide some days and two or three tides on other days. During full and new moons, we expect the tidal range to be greater than during the quarters and half moon phase. Since the moon rises one hour later every day, it was long suspected that it had an influence on the tides. In theory, if the ocean uniformly covered the earth, the moon’s gravitational force would act equally, deforming it and creating significant tidal effects. The moon also affects the earth’s mass so that the ocean on opposite sides experiences high tides as the earth is pulled away from the water. As the moon rotates around the earth, there are two high tides and two low tides at any given time.

In reality, the oceans do not cover the earth uniformly and they vary in depth. There is also significant friction exerted between the oceans and the earth’s surface. Other objects in the solar system influence the tides as well. Most are negligible, except for the sun, which has approximately one half the influence of the moon. All of these combine to make tidal predictions extremely complex.

When the sun and the moon line up at the full and new moon, their combined influence creates a greater pull, and we experience strong or spring tide. When the sun and moon are at right angles to each other, during the moon’s first and last quarter, they interfere with each other and we experience weak or neap tides. In addition, the tidal ranges are greater when the moon and sun are at perigee, or closest to the earth.

For anglers, a general understanding of the tides is useful, but a tide chart is necessary to predict them accurately. Charts are helpful, but experience alone will teach the angler how to benefit from the myriad factors that coincide with the tide to produce good fishing.