Norra Kvarken

a strait in the Baltic Sea, in the western part of the Vaasa Skerries. The strait, which measures 75 km wide, unites the northern (Bottenvik) and southern (Bottenhav) parts of the Gulf of Bothnia. A group of islands divides theNorra Kvarken into two straits—the eastern Kvarken and thewestern Kvarken. The depth of the eastern Kvarken is 6–7 m;the western Kvarken has depths up to 29 m. The currents dependon the winds and the atmospheric pressure. The strait freezesduring the winter.