How Do Tides Affect Marine Life?

Tides affect marine life by causing fish to gather in one spot, depending on the species and water depth. Strong tidal currents cause a concentration of bait and smaller fish that attracts larger fish to the area. Predicting tides is a tool fishermen use to improve their catches.

Organisms living in intertidal zones must be able to live both above and below water, depending on the

tide. Other organisms that depend on tides for survival include coral reefs, which depend on tides to deliver food to them.

The distances and positions of the sun, moon and Earth all affect the size and strength of the Earth’s tides. The magnitude of tides are also strongly influenced by the shape of the shoreline. The height of tides is greatest when tides hit a wide portion of the continent. On the other hand, mid-oceanic islands usually experience very small tides because they are positioned further away from the continent.

Tides carry nutrients, moderate temperatures and influence other conditions. High tide refers to water at its highest level, and low tide is water at its lowest level. Ebb, or falling, tide occurs when the water seems to flow back out between a high tide and a low tide. When the water flows back in between low tide and high tide, this period of time is known as flow, flood or rising tide.

Each of the Earth's two tidal bulges travel at a speed of approximately 24 hours, which means there are two high tides and two low tides each day, with high tides occurring 12 hours and 24 minutes apart.