The Skagerrak is a strait running between the southeast coast of Norway, the southwest coast of Sweden, and the Jutland peninsula of Denmark, connecting the North Sea and the Kattegat sea area, which leads to the Baltic Sea.

The Skagerrak is 240 km long and between 80 and 140 km wide. It deepens toward the Norwegian coast, reaching over 700 metres at the Norwegian Trench. Some ports along the Skagerrak are Oslo and Kristiansand in Norway and Uddevalla and Strömstad in Sweden.

The Skagerrak has a salinity of 30 practical salinity units. The area available to biomass is about 3,600 km2 , including a wide variety of habitats from the sandbanks to Sweden and Denmark to the deeps of the Norwegian trench.