Baltic Sea as species in 2005 and 2018 respectively, having formerly been confused with more widespread relatives. The tiny Copenhagen cockle ("Parvicardium hauniense"), a rare mussel, is sometimes considered endemic, but has now been recorded in the Mediterranean. However, some consider non-Baltic records to be misidentifications of juvenile lagoon cockles ("Cerastoderma glaucum"). Several widespread marine species have distinctive subpopulations in the Baltic Sea adapted to the low salinity, such as the Baltic Sea forms of the Atlantic herring and lumpsucker, which are smaller than the widespread forms in the North Atlantic. A peculiar feature of the fauna is that it contains a
Book of the Consulate of the Sea of the Ribera (seaside), which in 1282 were named "consols de mar" ("consuls of sea"). Many authors believe that the laws specified in the "Book of the Consulate of the Sea" had a big influence on all other compilations of maritime law in Europe, which are partly based on it. Some of these laws specified in the "Book of the Consulate of the Sea" were already adopted in the ninth century in places like the Baltic, the North Sea, the Schleswig sea: Riga, Wisby, Hamburg, Lübeck and other cities of the Hanseatic League, being published since 1407 under the title