New technology for fish farming

Robot can make light work of net cleaning

Above: Workers pulling up a net for cleaning at Marine Life Aquaculture. Left: Dr Koh Poh Koon checking out an underwater robot that can clean nets at the exhibition in Norway last month. With him is Marine Life Aquaculture managing director Frank Ta
Workers pulling up a net for cleaning at Marine Life Aquaculture. PHOTOS: DIOS VINCOY JR FOR THE STRAITS TIMES, AUDREY TAN
Above: Workers pulling up a net for cleaning at Marine Life Aquaculture. Left: Dr Koh Poh Koon checking out an underwater robot that can clean nets at the exhibition in Norway last month. With him is Marine Life Aquaculture managing director Frank Ta
Dr Koh Poh Koon (left) checking out an underwater robot that can clean nets at the exhibition in Norway last month. With him is Marine Life Aquaculture managing director Frank Tan.PHOTOS: DIOS VINCOY JR FOR THE STRAITS TIMES, AUDREY TAN
Above: Workers pulling up a net for cleaning at Marine Life Aquaculture. Left: Dr Koh Poh Koon checking out an underwater robot that can clean nets at the exhibition in Norway last month. With him is Marine Life Aquaculture managing director Frank Ta
Dr Dirk Eichelberger of Singapore Aquaculture Technologies PHOTOS: DIOS VINCOY JR FOR THE STRAITS TIMES, AUDREY TAN

Norway is almost synonymous with salmon, and its aquaculture industry is one of the world's biggest. Singapore government officials and fish farmers were recently in the Nordic country to attend Aqua Nor, the world's largest aquaculture technology exhibition. The Straits Times reports on how novel technologies being developed abroad and in Singapore can be a shot in the arm for the fish farming industry here.

Hoisting nets out of the sea for cleaning is a back-breaking task.

Yet, it is a job that fish farmers in Singapore have to do regularly - about once every three days - to ensure the nets do not get clogged and that reared fish can grow healthily.

However, new technology in the form of underwater robots could make light work of this.

Such robots recently caught the eye of local fish farmers at Aqua Nor - the world's largest aquaculture technology exhibition held in Trondheim, Norway, last month.

The robots, which cost about $200,000 each, can be remotely controlled from land.

They work by plying the nets and cleaning them with high-pressure pumps. This way, substances clogging the nets, such as algae or mussels, can be flushed out.

There are also built-in cameras on these robots, which will help the farmers see if the net has been cleaned to their satisfaction, or if another round of cleaning is needed. They also enable farmers to check for holes in the net.

It is a technology that fish farmer Frank Tan, 43, is considering for his farm in the Johor Strait, where many of Singapore's other coastal fish farms are located.

At most of these farms, nets are left submerged in the sea to house fish. However, they are easily dirtied in Singapore's nutrient-rich waters.

For example, when algae or soft coral grow on the nets, water flow is obstructed and oxygen levels are reduced. The debris, which includes algae, also prevents currents from flushing out fish waste, which could cause bacteria to grow.

Speaking to The Straits Times on the sidelines of the exhibition in Norway, Mr Tan, managing director of Marine Life Aquaculture, said: "Each net is cleaned once every three days. But because we have many pens, nets are hoisted and washed almost every day."

He said that each net, when dry, weighs about 1,200kg. However, it feels twice as heavy when it is wet. As many as six workers are needed to hoist a net each time.

But with the robot, Mr Tan predicts the job can be done by just one person, and only once a week.

Said Mr Tan: "The robotic net washer will save me a lot of time and man hours. It will also help to boost productivity, as I can clean the net with the fishes still in there." Currently, fishes have to be manually moved to a different pen whenever a net is being washed.

Mr Tan was part of a delegation from Singapore which visited Norway last month to attend the Aqua Nor exhibition and to learn about Norwegian aquaculture technologies and methods.

Led by Senior Minister of State for National Development Koh Poh Koon, the delegation comprised fish farmers as well as officials from the Ministry of National Development, the Agri-Food and Veterinary Authority (AVA) and other agencies.

Mr Tan said he plans to apply for AVA's Agriculture Productivity Fund to co-fund the purchase of the robot. He said: "This trip provided a good opportunity and platform for government officials and fish farmers to come together and discuss how various technologies could be applied in Singapore's coastal farms to increase productivity and capacity.

"With such discussions between regulator and farmers, traditional fish farming could turn into a new high-tech industry and play an import role in national food resilience."

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A version of this article appeared in the print edition of The Straits Times on September 01, 2017, with the headline 'Robot can make light work of net cleaning'. Print Edition | Subscribe