The fisheries department has started sinking 200 artificial reef structures at 10 locations between Ennore and Akkarai along the East Coast. The work, which began a few days ago, will entail a cost of ₹4 crore. The structures measuring six feet in length and three feet in width, will be sunk at identified locations five nautical miles from the shoreline and the substratum will be sunk at a depth of 12 metres using ropes, said a senior official from the department.
These concrete structures are sunk mainly to attract fish and over some time the fish aggregation on these structures will increase. They are also known as fish aggregating devices. The sinking work will be completed in a month, said the officer.
Asked about sinking such substratum under the seabed, a Zoological Survey of India officer said there were divided opinions about sinking such substratum at the bottom of the sea. It helps to some extent with fish aggregation. Whether these structures will help in increasing the fish diversity or faunal diversity around them is a debatable one, he said.
It will take a longer time for the fish to aggregate in large numbers under these artificial structures. Another idea of sinking such structures is to create artificial reef formations around them. It will take at least 10 years to form an artificial reef around these structures. Sinking these structures at 5 nautical miles from the shoreline at a depth of 12 meters is ideal, as these structures will not affect the movement of fishin boats, the officer explained.