Norwegian researchers test lice treatment when restocking

摘要

Treated fry are often a little larger after one year in the ocean than those that do not receive anti-lice treatment, according to a study that took place in Hordaland, Norway between 1997-2011. "From 1997 to 2009, we treated salmon smolts against sealice before we put them out, and later we caught the salmon when they returned to the river," says Ove Skilbrei from the Institute for Marine Research (IMR). "This catch has both given us estimates of the importance of salmon lice and shown us how the conditions in the sea have varied," he says. The study was conducted by researchers from IMR, Norwegian Institute for Nature Research (NINA), Radgivende Biologer (Advisory Biologists) and the Norwegian Institute for Water Research (NIVA). Throughout the period, juveniles that were treated against lice proved to be 15% more likely to survive and be recaptured as adult salmon than untreated fish. The risk of getting lice was however not evenly distributed among the different years, but was most evident in1997,2002 and 2007.