Fish farming ‘not to blame for algae outbreak’

Farms in northern Norway have been hit by the algal bloom

NORWAY’S leading marine scientists have poured cold water on claims that fish farming may be to blame for the devastating algae outbreak, which has destroyed almost eight million salmon in the north of the country during the past ten days.

The industry has been angered by suggestions from some environmental and green groups that the high concentration of fish farms could be a major factor.

So far more than 7.7 million fish worth at least two billion kroner have suffocated in the outbreak.

But Norway’s highly regarded Institute of Marine Research put out a statement yesterday saying that a review of the situation in the affected areas (Nordland and Troms) ‘shows that farming is probably not a causative factor’.

But it does add that ‘it cannot be ruled out the emission of nutrient salts from plants can prolong the bloom’.

The IMR said tests carried out in two affected fjords with fish farms (Ofotfjord in Nordland and Astafjord in Troms) have shown that the emissions were not significant enough to provide enough nutrients for such a large outbreak.

In Astafjord, emissions have only averaged 16 tonnes of fish per square kilometre and in Ofotfjord the figure was 51.5 tonnes per square km.

For such a risk to occur, the emissions would have to be at least 200 tonnes per square km, said Vivian Husa, who researches such risks for the IMR.

She said there were some high production fjords in Norway with emissions of at least 200 tonnes, but they have not been hit by an algae bloom over the past 20 years.

‘If discharges of nutrients from fish farming had been the cause of such blooms of harmful algae, we could have expected regular blooms in fjords with a high farming intensity,’ she said.

Fisheries minister Harald Tom Nesvik accused left wing groups of trying to make capital out of the crisis and said he hoped the IMR’s findings would now take some of the heat out of the debate.

He added: ‘The crisis is not over and much more research is needed in the affected areas. But I hope that we can now avoid politicians trying to make political capital while we are in the middle of a disaster.’