The Site includes the major part of the Vest-Vikna archipelago, and consists of several larger islands and numerous islets in shallow marine waters. The landscape has a mosaic pattern including rocky shores, narrow mires and bogs, and sparse vegetation fertilized by seabird guano. Some of the islands are covered by a nationally endangered heathland mosaic with bogs and ponds. More than 345 vascular plant species have been recorded, with several species at the northernmost or southernmost limits of their range. The large mires constitute important water reservoirs during dry periods and play an important flood control role during periods of heavy precipitation. The wetland supports breeding, staging and wintering populations of many nationally threatened species such as the black guillemot Cepphus grylle, the Atlantic puffin Fratercula arctica, and the black-legged kittiwake Rissa tridactyla. The islets hold populations of grey seal Halichoerus grypus and harbour seal Phoca vitulina. More rarely, false killer whale Pseudorca crassidens and Eurasian otter Lutra lutra visit the archipelago. European roe deer Capreolus capreolus is common on some of the islands. The Site is used for fishing and agriculture.