S. Sandoy et Rm. Langaker, Atlantic salmon and acidification in Southern Norway: A disaster in the 20th century, but a hope for the future?, WATER A S P, 130(1-4), 2001, pp. 1343-1348
Due to acidification, 18 Norwegian stocks of Atlantic salmon are extinct an
d an additional 8 are threatened. In the two southernmost counties, salmon
is eradicated. Due to the high acid sensitivity, production of salmon was g
reatly reduced as early as 1920, several decades before acid rain was recog
nized as an environmental problem. International agreements on reduced atmo
spheric emissions will reduce acidification effects in Norway substantially
during the coming 20 to 50 years. However, the extreme acid sensitivity of
salmon makes the destiny of this species in Southern Norway uncertain. Lim
ing is an effective measure to protect and restore fish populations in acid
ified waters. Liming of acidified salmon rivers has become important in Nor
way in recent years which in combination with reduced emissions will be an
important contribution to protection of the Atlantic salmon species. In thi
s paper we give an overview of the effects of acidification on Norwegian sa
lmon and discuss different aspects of mitigation measures; the expected eff
ect of international agreements on reduced atmospheric emissions, the expec
ted effect of liming on salmon production and the possibilities of re-estab
lishing self sustaining salmon stocks in limed rivers.