HƯNG YÊN — As natural rivers in the countryside have become more and more contaminated with rubbish, a young farmer in Mỹ Hào District of northern Hưng Yên Province has created artificial streams to raise healthy fish.

Vũ Duy Hào left his professional boxing career several years ago and started to help his mother with aquaculture farming.

Hào’s mother, Vũ Thị Thắm, is the owner of an aquaculture co-operative which provides aquatic products for the area. One day, she attended a farming conference and heard about man-made streams in the US which yielded up to 37 tonnes of fish per 100 sq.m.

After the conference she got her hands on documents about the model. None of the farmers seemed to be interested in the model except for Thắm. The quality of the fish raised in the streams was said to be very good because fish are isolated from mud.

Meanwhile, fish raised in her calm pond moved very little and their digestive process remained slow, with the fish smelling like mud.

The hope of raising uncontaminated fish motivated Thắm to do further research and apply the model to her co-operative.

Thắm told the idea to her son Hào studied the documents for a few days and planned a man-made river.

Failures by failures

The first river 25m long, 5m wide and 2m deep, was constructed with bricks and a concrete foundation. All the streams are within a 3,000sq.m pond.

A pumping system was built under by the river, with a pipe that pumps air to create an underground current into the river and pumps out fish waste.

Hào said that there is a high density of fish raised in each river. About 200 to 300 are raised in the pond to purify water which is fed to the streams.

Hào’s first attempt to raise fish with the new method was unsuccessful. The vault roof with the air pumping system failed to supply enough oxygen, leading to the death of four tonnes of cá diêu hồng (red tilapia) and carp.

The next attempts were also failures. The new iron roof material rusted and the fish net broke, allowing the fish to swim from the river to the pond.

After several similar setbacks, Hào had to start from scratch. However, each failure taught him a lesson. After four generations of fish, he gradually completed the model with improvements compared with the US model.

“At least one hectare of water surface is needed to build three streams to yield the best production. Fish are raised in high density so the electricity current must be like blood in the body to operate oxygen machines to help fish breathe,” he said.

Productive

As many as 15 streams have been built in Hào’s pond with total cost of about VNĐ5-6 billion.

“I call them the sporty fish as they swim all the time. Fish raised in the calm pond are fed twice a day, sometimes they drop the meals but fish in the streams are fed four times daily,” he said.

“Fish in the streams consume high-protein food and are supplied with oxygen so they grow very fast. The fish look very firm and healthy. They taste very good instead of being smelly and contaminated with mud like fish raised in the pond,” Hào said.

The water in the streams is so nutritious that it is used for aquatic technology to grow clean vegetables in the net house.

Hào has transferred the technology and so far sold 20 streams to farmers in northern Hải Dương Province, central Thanh Hóa Province and Hà Nội.

Hào said that the total investment of a man-made river including materials and equipment is about VNĐ120-150 million.

“I only want to pass on green technology to the community so that our country has clean farm produce to consume,” Hào said, adding that he has expected to receive feedback from farmers to further improve the streams. — VNS