The blooming of poisonous algaes, the epidemic of deaths among the seals and the influence of the North Sea have all given rise to grave concern about the increasing risks for the Skagerrak.
The Skagerrak is the least investigated area of all our sea regions. The coastal regions and particularly the fiords have been given much attention but the hydrographic conditions in the open Skagerrak have been regarded as oceanic and the Skagerrak has not been considered to be exposed to pollution or eutrophication.
A summary of the hydrography of the Skagerrak is hereby presented as an introduction to the increasing investigation and monitoring of the environmental eon di tions of the Skagerrak.