Shrimp farms in Latin America produce a quarter of the three million tonnes of shrimp consumed worldwide each year. Consequently, shrimp farmers are destroying the mangrove forests to make shrimp ponds. Mangroves nurture a very delicate ecosystem and serve as important nurseries for many species of fish. They also protect the low-lying land behind them. Asian shrimp farmers prefer to make new ponds by felling the mangroves rather than maintaining the old ones. This damages the ecosystem. In India and some other Asian countries, shrimp farms are generally small and the farmers rear shrimp at very high densities to maximise the profit. The results in high waste generation out of the feed, as the shrimp only utilise less than 30 per cent of the feed. The waste then pollutes tidal waters, damaging local fisheries and fouling the bays.