The department said it has asked local farmers to stop using this method, but the cost of old rubber tyres is much cheaper than that of traditional materials, and there are currently no regulations banning this type of farming.

The sub-department estimates that there are about 1,000 oyster farming households in Vung Tau City, mainly in villages 4, 8, 9 and Ben Diep Village.

There are no specific numbers of households raising oysters with old rubber tyres. However, most households use tyres and roofing sheets for young oysters to attach to.

A farmer, who wished to remain anonymous, said she has raised oysters for more than 10 years in Village 3 in Long Son Commune.

She usually purchased bamboo and wooden poles and put them into the water for young oysters to attach to. However, the bamboo and wooden poles quickly deteriorated, so she had to replace them often.

In recent years, her family has tried other materials to reduce costs. Old tyres and roofing sheets worked best, she said.

She explained that the roofing sheets were easily broken by waves and each sheet could only be used for one crop.

Meanwhile, old tyres were very durable and could be used for many years. However, oysters that attached to the sheets would grow faster than those on old tyres. Oysters on the sheets could be harvested after 18 months while those on tyres could only be harvested after two years.

Therefore, many farming households have used both materials to breed oysters. Old tyres are hung around the farming area due to their high durability to strong waves and the sheets are placed in the middle of the area.

A representative of the People's Committee of Long Sơn Commune said the local farmers mainly used bamboo and wooden poles covered with cement. In this way, oysters had high quality and could be harvested after a year.

In recent years, some households tried other materials and found that young oysters attached best to rubber tyres, so people flocked to buy old tyres without considering their impact on people’s health and the environment.

Nguyen Huu Thi, deputy head of the provincial Fisheries Sub-Department, said the department has coordinated with the Economic Office of Vung Tau City and the Long Son Commune’s People's Committee to advise local people to use eco-friendly materials.

However, it is very difficult as the cost of old tyres was quite low, he said.

The sale of old rubber tires is common in Long Sơn Commune. Used tyres are collected and split in half with a length of about 60cm to 80cm. Each piece is perforated so that farmers can string two pieces together to hang on the raft.

Each piece of tyre is sold for just VND700. 

The provincial Fisheries Sub-Department has raised concerns over the toxic metals and chemicals, which might leach out of the tyres into the water and harm marine life. In addition, the dumping of old tyres into the sea could turn the natural area into a dumping ground.

Discarded tyres and roofing sheets will have direct and long-term effects on the farming environment. The department has sent staff to educate oyster farmers about the harmful effects caused by old tyres and sheets.

It has regularly taught people how to raise new oysters with oyster shells strung together and hung on rafts. Empty oyster shells will be strung together to attract young oysters. However, this method has not been applied, it said. 

Source: Vietnam News