Pearl River mouth 'too polluted' for rare marine life
Untreated sewage also makes water unsuitable for aquaculture or sports
The water at the mouth of the Pearl River is so badly polluted it is unsuitable for aquaculture or water sports and cannot sustain endangered species, according to a study.
Untreated human sewage was the main cause of the pollution, said the recent study by the Ministry of Agriculture, the State Environmental Protection Bureau and several other departments.
The water quality is so bad that 10 species of fish - including the little yellow croaker and sardines - have been severely affected. 'Pollution is a long-standing problem in the Pearl River, but aquaculture in the river system has already ended,' said an official at the Guangdong Provincial Oceanic and Fishery Administration.
'Farmers are now breeding in tanks, but production in the Pearl River Delta is on the decline.
'We promote safe fisheries, but not in the river,' the official said, adding that the output of Guangdong's fisheries has been growing at an annual 6 to 7 per cent, but much of the growth is in eastern and western Guangdong.
A section chief of the Zhuhai Oceanic and Fishery Bureau, Liang Guoping , said the city had 7,000 hectares of aquaculture farms at the end of last year with an output of more than 400 million yuan, including 200 hectares of oyster beds near the coastline.
'Production in the coastal areas has fallen because of silting, land reclamation and pollution and deep-sea aquaculture is still growing,' he said.
Zhuhai's oysters and crabs are seen as delicacies, but experts have warned that it is not safe to raise them within 1km of the coastline.
A Shenzhen fisheries official, meanwhile, said the city still had 4,592 hectares under aquaculture last year, with production valued at 321 million yuan. The farms are mainly in Longang, as reclamation, red tides and pollution have closed down many farms in Baoan.
Shenzhen has the capacity to treat 100 per cent of its sewage, but 40 per cent of the waste water is not channelled into the system because residents build illegal extensions to their homes and drain waste down rain gutters.
Dapengwan and Shenzhen Bay are so polluted that there were 10 red tides last year, accounting for two thirds of those in the province.
Red tides are blooms of harmful algae which multiply rapidly, feed on pollutants from fertilisers and sewage, kill fish and make other seafood toxic to consume.
Shenzhen environmental experts say most of the city's waste water flows into the sheltered Shenzhen Bay where it accumulates, creating favourable conditions for red tides.
The central government report on May 16 said the main pollutants were phosphorus, lead and nitrogen. The experts recommended that delta cities improved their waste-water treatment.
