Fisheries at the Estonian Baltic Sea coast in the first half of the 19th century: What can be learned from the archives of Karl Ernst Baer?

The Baltic German naturalist Karl Ernst von Baer (1792-1876) laid the foundations for several scientific disciplines in the Russian Empire, including fish biology and fisheries. This paper presents original material gathered from Baer's archives in St. Petersburg related to the activities of special expeditions conducted under his leadership in the years 1851 and 1852. These archives are an important source for description of fisheries and quantification of fish catches, first of all herring Clupea harengus membras, along the Baltic Sea coasts of the Russian Baltic Sea provinces (today's Estonian territory) during the first half of the 19th century. The longest dataset found in these archives covers over 50 years (1796-1851). It consists of landings of several commercially exploited species, including herring, pike Esox lucius, perch Perca fluviatilis, roach Rutilus rutilus and ide Leuciscus idus, in one manor on Hiiumaa Island. Amongst various documents, the archives contain information on fishing gear, taxation of fishing equipment, the best fishing seasons and locations, and some explanations for a decrease in fish stocks. Baer concluded that fluctuations of the Baltic herring fisheries in the Estonian coastal areas during the first half of the 19th century were governed by weather conditions, rejecting thus the initial hypothesis on the long-term decrease of herring in the sea caused by fishing. Based on the current knowledge of fisheries science, Baer's suggestion of a possible influence of weather and also some other statements on the dynamics of fish catches seem to be justified while some of the conclusions may require re-evaluation, at least partly.