Fish is an important item in the Swedish diet, and Sweden is both a major importer of fish products and a principal supplier to other countries. Göteborg, Bohus, and Halland are the principal fishing districts, but large quantities of fish are caught all along the coasts. At the beginning of 2001, there were 1,851 vessels in the Swedish fishing fleet, with 2,576 professional fishermen. Herring, cod, plaice, flounder, salmon, eel, mackerel, and shellfish are the most important saltwater varieties. Freshwater fish include trout, salmon, and crayfish, a national delicacy. The saltwater fish catch increased from 228,000 tons in 1971 to 259,000 tons in 1984, overcoming a significant drop in the 1974–79 period because of government conservation measures and the declining number of fishermen. The total catch amounted to 305,700 tons in 2001. By tradition, a large part of the annual catch is landed in Denmark. Total landings were valued at $114 million in 2001. Herring and cod accounted for 23% and 7%, respectively, of total landings.