Importance of Tides

Marine ecosystem

  • Tides affect marine ecosystems by influencing the kinds of plants and animals that thrive in what is known as the intertidal zone—the area between high and low tide.
  • Because the area is alternately covered and uncovered by the ocean throughout the day, plants and animals must be able to survive both underwater and out in the air and sunlight. They must also be able to withstand crashing waves.
  • For example, plants and animals that can anchor themselves to the rocks along a shoreline can survive the lashing from waves and the less violent movement of the changing tides.
  • Sand crabs not only burrow to survive, they actually follow the tides to maintain just the right depth in the wet sand.
  • Along many shorelines, tides form tide pools. These small pools of water are often left behind among the rocks at low tide. They can include a diverse population of tiny plants and animals that may serve as food for larger species.


  • Tidal heights are very important, especially harbours near rivers and within estuaries having shallow ‘bars’ [Marine Landforms]at the entrance, which prevent ships and boats from entering into the harbour.
  • High tides help in navigation. They raise the water level close to the shores. This helps the ships to arrive at the harbour more easily.
  • Tides generally help in making some of the rivers navigable for ocean-going vessels. London and Calcutta[Tidal Ports] have become important ports owing to the tidal nature of the mouths of the Thames and Hooghly respectively.


  • The high tides also help in fishing. Many more fish come closer to the shore during the high tide. This enables fishermen to get a plentiful catch.

Pollution mitigation

  • Tides are also helpful in desilting the sediments and in removing polluted water from river estuaries.

Power generation

  • Tides are used to generate electrical power (in Canada, France, Russia, and China).