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Sea Lice Numbers Lower During Spring

18 June 2013

NORWAY - Sea lice levels have been low during spring this year and in many places, numbers were lower than the same period last year.

Monitoring shows that sea lice pressure on wild salmonids has been low and that the majority of salmon smolts probably came out with little lice.

"Low water temperatures, well coordinated delousing and good supervision is why our situation has been so good," says Kristina Landsverk, supervising director of the FSA.

During the period January to June 2013, sealice numbers were lower than in recent years. Across the country, the average level remained below the maximum threshold of 0.5 adult females, ie the limit of lice that may be on farmed fish at a facility.

"The low lice levels is primarily due to low water temperatures. Temperatures have been up to two degrees below normal and low water temperatures mean salmon lice reproduce more slowly," says Ms Landsverk.

The sea lice infection of wild salmon is also lower this year than in previous years.

So far, the results indicate that 2013 is a year of very low infection pressure along parts of West and Central Norway in the spring and early summer, and both sea trout smolt and salmon smolts have been low infection during smolt migration.

This may be due to measures taken by government and industry, but can also be caused by low temperatures and lots of fresh water in the spring and early summer.

You can read more on the report here.

TheFishSite News Desk



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