Kattegat

The Kattegat is a 30,000 km2 sea area located between the Jutlandic peninsula, Denmark, and the provinces of Bohuslän, Västergötland, Halland, and Scania in Sweden. It is a continuation of the Skagerrak and a bay of the North Sea and North Atlantic Ocean, bounded by the Danish straits to the south. The Kattegat is a shallow sea with many sandy and stony reefs, making it difficult to navigate, but has been made safer with artificial seabed channels and a light signaling network.learn more on wikipedia