Q. Which among the following statements is / are correct?
- Tides are of great help in navigation and fishing
- High tide enables big ships to enter or leave the harbour safely
- Tide prevents siltation in the harbours
- Kandla and Diamond Harbour are tidal ports
- The tidal nature of the mouth of the river Hooghly is of crucial importance to Kolkata as port
Select the correct option from the codes given below:
Answer:
1, 2, 3, 4 & 5
Notes: Tides and Fishing
Tides move water, bringing water in and taking water out. Understanding the cycles and effects of tides on fish helps in better fishing. The full and new moons normally create better fishing conditions because of the spring tides. The reason behind this is that fish are easier to catch when they are feeding and it’s the tide and currents that dictate this. When the water begins to move, smaller fishes are at the mercy of the current and get confused in the turbulent water. Larger fishes have an advantage because they are equipped to feed in this turbulent water. These larger fishes get more easily trapped when there are tides.
Tidal Ports
During high tides, water rushes into harbours (Tidal Bore). This helps ships enter and exit harbours safely. High tides make ocean/sea water rush into the mouths of rivers. This helps ships to enter port towns like New York, London, Rotterdam, and Hamburg. This is perfectly advantageous for some ports in India such as Kandla, Mangalore and Kolkata’s diamond harbour.
Tides and Siltation
Tides take away the terrigenous material brought by the rivers at the river harbours and thus help in the prevention of siltation.
Tides and Prevention of Rivers from Freezing
The temperature at which sea water freezes is much lower than that of river water. In cities like London, due to the high tide, the sea water enters the river and prevents it from freezing.