Undercurrent News, 2 Oct 2013: Salmon farms rushing to slaughter 8,000 tonne of fish due to high lice levels

Undercurrent News, 2 Oct 2013: Salmon farms rushing to slaughter 8,000 tonne of fish due to high lice levels

By: Eva Tallaksen

Five Norwegian salmon producers are mass-slaughtering some 8,000 metric tons of salmon from their pens in an area north of Vikna, central Norway, due to high lice levels.

Three of those, Marine Harvest, Emilsen Fisk and Midt-Norsk Havbruk, are rushing to empty some 5,000 metric tons within deadlines set by the Norwegian food safety authority (NFSA).

In late August, the authority had informed these three producers that they would have to slaughter all their salmon in the area, after all other measures to counter the lice infestation failed.

Vikna, located in Ytre Namdal, in Nord Trondelag, is one of the busiest salmon farming regions in Norway.

The three producers had levels of five to six mature female lice per fish in the area affected — far above the national limit of 0.5/fish, said John Bjarne Falch, regional director of NFSA.

NFSA has ordered the producers to slaughter all their fish, or face a fine of approximately NOK 100,000 per day, for every day extending beyond the deadline, said Falch. One producer has to slaughter its fish by Oct. 3, another by Oct. 10 and the third by Oct. 23.

“It’s a question of capacity,” Falch told Undercurrent News. “The slaughterhouses are running at full steam, so the deadlines just reflect how fast they can empty their pens.”

Two other producers, Sinkaberg-Hansen and Salmonor, also operate in the same area. While these have not reached the national limit, they have come very close to it, and have decided to slaughter the fish of their own accord, said Falch.

This means some 8,000t are now being harvested from the area this month, he said. The fish affected are around 3.5-4kg in size, on average.

Need for bigger zone, better management

The farms in the area had started to show signs of resistance to traditional anti-lice measures. The producers had managed to deal with the situation so far, with best practices and biological means, but by the spring, it started becoming problematic, said Falch. The summer then intensified the situation, as sea lice reproduce faster in warmer waters.

Under Norwegian regulations, when a farm first exceeds its lice level limit, NFSA orders it to address the situation using all delousing methods available. Failing which, as in this case, the authority orders the affected pens to be emptied of all fish.

In Falch’s view, part of the problem in Vikna is that the farming zone designated for the area was too small. In Norway, salmon farming areas are divided into zones, in which farms must comply to certain rules on sizes and biomass, and must empty their pens and fallow at the same time.

This fallowing time is usually key in regulating sea lice, as they disappear when the fish are harvested, and are at their lowest levels when farming resumes. In this case, however, because the zone is small, the farms were getting infected immediately after fallowing from lice in neighboring zones, said Falch.

As a result, NFSA is working on expanding the zone in question. The area will also be ordered to fallow for the whole of February and March next year, he said.

Another issue, he said, is to do with how the farms are managed. “A bit further south, we have some farms, the same type of site, which have managed to keep the lice levels at 0.06 per fish — a tenth of what the regulation says.”

These sites do not have any other delousing methods than the ones north of Vikna, he said, showing the importance of good management. “If you use delousing products too early, for instance, you incur a higher risk of creating resistance among the fish.”

http://www.undercurrentnews.com/2013/10/02/salmon-farms-rushing-to-slaughter-8000t-fish-due-to-high-lice-levels/#.UkwQedVwY5t

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