Junior Cycle Geography CYCLONE 24.4 Sustainable Exploitation of Fish: Ireland


Even though fish are a renewable resource, they are being rapidly overfished in many parts of the world. Overfishing occurs when fish are taken from the sea faster than they can reproduce. When this happens, fish stocks decrease quickly and become depleted (used up).


Why Is Overfishing Happening? There are a number of causes of overfishing:


 Efficient ships: Super-trawlers have increased the amount of fish caught each year. These ships can catch fish and then store their catch in huge refrigerators to preserve them. Smaller ships take the catch back to land, while trawlers remain at sea. The super-trawler in figure 3 below is called the Margiris. It is 142 m long. In 2015, it was investigated for illegal fishing in Irish waters.


 Improved technology: Super-trawlers have improved capability to locate fish. They use echo sounders and sonar equipment to locate shoals (large groups of fish). Powerful motorised winch cranes can haul in huge nets full of fish.


 Netting: Monofilament nets are hard for fish to see. They can stretch to many different lengths (depending on the laws of the country in control of the fishing waters) and hang like massive curtains in the water. Trawl nets scoop fish from the bottom of the sea floor.


 Different types of commercial fishing: Developments in modern commercial fishing have led to increased catches. Countries are allowed to catch more fish to meet the needs of their growing populations.


Airbus A380: 72.75 m


Sydney Opera House: 185 m Queen Mary II: 311 m Titanic: 269 m Margiris: 142 m


Super-trawler Margiris's net is 600 m long and can open to 200 m wide.This is large enough to hold eight jumbo jets.


3. The size and fishing range of super-trawler Margiris 360


FUN FACT! Overfishing means that


three-quarters of the world’s fish


stocks are being harvested faster than they can reproduce. If current trends continue, the world’s food fisheries could be completely eliminated by 2050.


NOT SO


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