Toxic Algal Bloom in Scandinavian Waters, May–June 1988

Abstract

In 1988, the alga Chrysochromulina polylepis had a massive and unpredicted bloom during May and June in the Skagerrak-Kattegat area, where it occasionally outgrew all other algae. Four weeks after its outbreak in the eastern Skagerrak, the bloom covered major parts of the Kattegat and the Skagerrak, causing kills of both wild and caged fish. The bloom spread northwards with the Norwegian Coastal Current (NCC) along the western coast of Norway to about 60 degree N. In spite of the high concentrations of cells (up to 100 million cells per liter, Berge, et al., 1988), the bloom was not very striking visually, partly because maximal algal populations often were found at some depth. The bloom was mainly noticed by its lethal effect on caged fish in fish farms along the coast. About 500 tons of caged fish with a market value of approximately $5 million US were lost along the southern coast of Norway before precautions were taken. (DBO)