Algal blooms cause big problems for salmon farmers. Photo: Marine Harvest

Feat of clay: new bid to tackle harmful algal blooms

A method developed by Chinese scientists is being applied in the fight against harmful algal blooms (HABs) that have cost the salmon industry millions.

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The technique, known as flocculation, has been shown to convert green microalgae-laden water into clear crystal water in China, and now Chile's Salmon Industry Association, SalmonChile, is trying to implement it in the south of the country, reports Pablo Tirado in Chile's El Mercurio newspaper.

Salmon farmers intend to use flocculation to combat, among other things, the harmful algae blooms that last year meant the loss of 39,000 tonnes of salmon in Chile. HABs also hit parts of Scotland hard in 2015.

According to David Farcas, general manager of the research laboratory for Chile's Centrovet agricultural and veterinary industry, the project started some time ago when they were approached from the Technical Institute of Salmon (INTESAL), SalmonChile’s technical branch, with the idea of adapting the patented technique by Chinese scientists for the Chilean industry, reports El Mercurio.

"It is a question of using clay, which is a natural component of the sea, to capture microalgae and finally eliminate it. The technology developed by the Oceanographic Institute of China consists in modifying the electrical charge of the clay surface in such a way that when it contacts the microalgae, it sticks and then sinks into the sea floor, where it cannot develop due to the lack of oxygen in the depth," explains Farcas.

Reduce the risk of algae

The latest tests of the technology are currently being carried out in the United States to validate the best way to use the clay and to specifically control the microalgae that have affected the salmon industry.

"The idea is that it is a solution to Chile's specific problems, so we have to get approvals from environmental authorities, which we hope will materialise in 2018," says Farcas.

He comments that the intention is to incorporate relevant governmental entities into the process, since the technology also has the potential to mitigate the damage HABs mussel farming and artisanal fishing.

"The idea is that this technology can effectively help reduce the risk of algae blooms, along with other technology that is being implemented by salmon companies to monitor and mitigate the impact of microalgae," concludes Farcas.