Kosterhavet boasts remarkable marine biodiversity, home to unique species like the deep-water coral Lophelia pertusa and the rare shellfish Haploops. The waters teem with seals, porpoises, and numerous fish species, including cod and mackerel. The archipelago serves as an important breeding ground for seabirds, with colonies of eiders, arctic terns, and oystercatchers. The park's waters also support a sustainable population of the famous Koster shrimp.
The marine park hosts an exceptional diversity of marine plants, including rare seaweed species and extensive seagrass meadows. Over 6,000 marine species have been documented, with unique cold-water coral reefs and kelp forests thriving in the deeper waters. On land, the islands feature distinctive coastal heathlands, characterized by hardy species like heather, juniper, and various coastal grasses adapted to the maritime environment.
The Kosterhavet region features a unique geological landscape formed during the last ice age, characterized by smooth granite cliffs, deep marine trenches, and a complex network of underwater canyons. The Koster Fjord, reaching depths of 247 meters, represents Sweden's most marine environment. The area's bedrock consists primarily of ancient gneiss and granite, dating back 1.6 billion years, with distinctive red granite formations visible along the coastline.
The Koster archipelago has been inhabited since the Stone Age, with fishing communities thriving here for centuries. The area gained prominence in the 18th century as a vital fishing and shipping route. Established as Sweden's first marine national park in 2009, Kosterhavet has historically been significant for its traditional fishing practices, particularly for shellfish like the famous Koster shrimp. The region's maritime heritage is preserved in local museums and continuing fishing traditions.
The park encompasses Sweden's most species-rich marine environment, featuring the Koster-Väderö Fjord as its crown jewel. Visitors can explore numerous hiking trails, pristine beaches, and traditional fishing villages across the Koster Islands. The park offers excellent opportunities for kayaking, diving, and snorkeling, with several underwater nature trails. The Naturum Kosterhavet visitor center provides interactive exhibitions and educational programs about marine life and conservation efforts.
Kosterhavet experiences a mild maritime climate influenced by the warm Gulf Stream, with summer temperatures averaging 17-20°C (63-68°F) and winter temperatures rarely dropping below freezing. The area receives moderate rainfall throughout the year, with slightly drier conditions in spring and early summer. The most pleasant time for visitors is between June and August when daylight extends up to 18 hours and water temperatures reach comfortable levels for swimming and water activities.
Sweden
58.8830°, 11.0170°
2009
389
Kosterhavet is Sweden's first marine national park, containing the country's most species-rich marine environment. The park encompasses the waters and islands around the Koster archipelago. It features unique coral reefs and marine life, with over 6,000 marine species in its waters.