Lice treatment
BY VINCE MCDONAGH
Heated argument Thermal cleansing is intended to rid fish of lice, but some argue it brings its own problems nies. Wri�ng in the journal and website Kyst og Fjord (Coast and Fjord), Karoline Skaar Amthor, Seafood Norway’s head of environment and health and the organisa�on’s communica�ons director Kris�n Langeland, both firmly rejected the allega�ons. They said: “All available research shows that this is wrong. Nowhere has it been shown that an exposure of fish for 30 seconds with water up to 34oC causes scalding and burns. “What we see is an escape response in the fish as a result of the warm water. It must be handled so that the fish does not injure itself during the short exposure �me. Risk reduc�on thus lies largely in planning, technical design and prac�cal implementa�on.” n intense debate is currently underway in Norway over the pracThey further added: “All handling of fish is to �ce of using warm water to remove salmon lice. the detriment of the fish. It is an independent Pitching environmentalists on one side and the industry on the goal to safeguard fish welfare throughout the other, it is an argument that could eventually impact on all northproduc�on cycle. We use a number of welfare ern hemisphere aquaculture businesses. parameters to assess whether the handling is In recent years, hot water treatment – some�mes described as thermal acceptable in rela�on to the purpose or not.” cleansing – has overtaken chemical and mechanical methods as the most Many industry experts with long experience common method of de-licing fish. It is a prac�ce which has received in this area argue that it is mainly condi�ons par�al veterinary approval. other than water temperatures which cause fish New studies, however, have suggested that using water above 28oC welfare problems. can cause salmon to show pain-related behaviour. Currently, salmon are Figures from the Norwegian Veterinary exposed to temperatures between 29oC and 34oC for around 30 seconds. Ins�tute show that the number of incidents of The salmon louse is a �ny parasi�c crustacean – not so far distant from high mortality a�er thermal treatment has been crabs or lobsters - that feeds on mucus, skin and �ssue fluids on salmodeclining. nids in the sea. Lice are also found on other fish. Norwegian Seafood’s Amthor and Langeland Although naturally occurring in salmonids, they have increased hugely maintain: “Mortality has not increased even due to intensive farming methods, with fish concentrated in small areas though volumes have increased, on the contraand in larger numbers crea�ng an opportunity for the parasite popula�on ry. We are gaining be�er knowledge about how to grow. to detect, diagnose and deal with disease-causThe claims around “thermal treatments” have led to inves�ga�ons (and ing organisms more quickly through drawing accusa�ons) on the part of a number of groups. lessons from one area of knowledge to the next. Toine Sannes, a leading Norwegian Green Party environmentalist, This has made Norway one of the world’s foreclaimed recently that the prac�ce led to salmon being scalded at �mes. most and most successful seafood producers.” This led to a sharp response from Seafood Norway, the employers’ “There has also been progress in terms of welorganisa�on which represents both aquaculture and sea fishing compafare and it will con�nue. Construc�ve cri�cism
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Left: Toine Sannes Opposite from top: The Voe Viking will usually treat three pens a day; Karoline Skaar Amthor; Kris�n Langeland; Lice on a salmon
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07/06/2021 16:13:06
