Surströmming is the Swedish name for soured herring. It essentially refers to fermented Baltic Sea Herring cuisine originating from the north of Sweden that is typically sold in tinned cans. The process may have been developed in order to keep relatively large catches, for as long as possible, with as little salt as possible.
Surströmming is thought to have probably originated when proper brining of fish was considerably more expensive due to the cost of salt. This meant that fish was thus kept in barrels with just adequate salt to prevent the fish from completely rotting. However, salt tolerant bacteria, such as the Haloanaerobium species, were able to grow and ferment the fish, mainly by decomposing the fish glycogen into organic.