Understanding the tides helps you know when to fish. Just like people, fish have active periods and rest periods. Unlike people, fish's actives are determined by the tides. The tide tells the fish when to be on the move for food and when to rest. Because fish don't have eyelids, they cannot close their eyes to rest. Instead, most species remain inactive during certain tides.
Tides are up-and-down movements of the oceans caused by the gravitational pull of the moon and the sun on the Earth. As the tide rises and falls, water flows in and out of bays, feeding behavior in fish. Whereas tidal changes have little effect far offshore and are of no concern to anglers who venture there in boats, tides are of the utmost importance when fishing inshore waters.
In most locations, the tide changes 4 times a day, resulting in 2 high tides and 2 low tides. Low tide occurs roughly 6 hours after high tide. At the end of each rising and falling tide, there is a period called 'slack tide', when there is little or no current, or movement of water, in or out of the bays, harbors, and estuaries. Slack tide usually lasts 2.75 to 3 hours, although it varies with location.
Published tide tables, such as those found in local newspapers, are general approximations. A strong wind from offshore can create a high tide sooner than predicted. When the wind is blowing against the incoming tide, the opposite occurs.
During slack tide, most saltwater predator fish that frequent inshore waters rest and do not seek food. Slack tide, therefore, is usually an unproductive time to fish inshore-which isn't to say that it's not worth a try. For example, anglers who like to be on the water at the very beginning of a tidal change often find themselves on the water during a slack tide. By presenting the proper bait, along with chumming or chunking, it is possible to provoke fish into feeding during a slack tide.
A rising tide is referred to as a 'flood tide'; a falling tide is called an 'ebb tide'. The change in water level is determined by the phase of the moon and the relative positions of the Earth, the moon and the sun.
Each month, the moon goes though 4 phases: new moon, first quarter, full moon, and last quarter (aka: third quarter). The new moon and the full moon occur when the moon, sun, and Earth are in a nearly direct line with one another. This increases the overall gravitational pull on the Earth, which causes relatively high high tides and relatively low low tides. These extreme tides are called 'spring tides', which has nothing to do with the season.
During the first quarter moon and the last quarter moon, the moon, sun, and Earth form the points of a triangle, with the Earth at the apex. This arrangement generates less gravitational pull on the earth, causing relatively low high tides and relatively high low tides. These more moderate tides are called 'neap tides'. Naturally, currents are stronger during spring tides than during neap tides.
Using the tide to Catch Fish
When the tide begins to ebb, the current forces baitfish into deeper water, concentrating them into smaller areas and making them easy prey for larger predator fish. The ebb tide thus trggers the predators' feeding instinct. Flood tides also trigger the feeding instinct and predator fish lie in wait for baitfish to flow into the mouths of inlets, bays, harbors, and estuaries or along the surf. Fishing action subsides during slack tides because baitfish disperse themselves, seeking shelter from predators. There are exceptions, but this is what happens with each ebb and flood tide for most areas on the East and West coasts and in the Gulf of Mexico.
As a rule of thumb, the best fishing takes place 1.5 to 2 hours after the ebb and flood tides begin. Tide tables appear daily in many newspapers, my website 
, and many tackle shops give them away. Read them for the approximate times, but remember that weather conditions can make the tides occur earlier or later than "scheduled," and not all fish feed during a rising or falling tide.
