Ghost nets – fishing nets that have been lost, dumped or abandoned – have emerged as the greatest killers of the underwater ecosystem in the seas off Kerala, says a study by an NGO. The stock of fish rearing and living under water is much larger in size and number than those populating the surface, according to Friends of Marine Life, the NGO.
Ghost nets, among other fishing gear that are accidentally lowered into the depths, now pose a major threat to the natural habitat and breeding ground of underwater fish. Many of the underwater reefs identified with flourishing fish stock have either been destroyed or are threatened by the ‘stifling cover’ cast by ghost nets. It is estimated that at least 10 per cent of the reduced fish catch globally could be blamed on ghost nets, some of which have survived deep underwater for decades together.
The issue even came up for discussion at the UN Ocean Conference recently in New York, said Robert Panippilla, Chief Coordinator, Friends of Marine Life. The long-term implications for marine life will be grave if no proper correctives are taken to deal with the menace The NGO’s study says there are four types of ghost nets that infest the bottom of the seas. The first are the large fishing vessels that stray into the territorial waters and deploy large nets.
At times, these nets get caught in underwater reefs, forcing the vessel to abandon them before leaving the territorial waters. The second type are smaller nets cast by fishermen, that are cut off by a passing vessel. These too drift down to the ocean floor and get attached to the rough features there. The third type of ghost nets refer to those that get caught in violent currents and swivel down to the ocean floor, where they get stuck. The fourth type are nets abandoned at sea after three or four uses. The nets remain under water for decades if not centuries.