The main reasons for this disappearance were twofold: on the one hand, the post-war years were a time of catastrophic pollution and eutrophication of the Baltic Sea. Unfiltered sewage flowed from the successively established industrial plants – some directly into the sea, others into rivers, which also ended up in the same place. The development of industry and the period of recovery from the devastation of World War II marked a time of ecological collapse for the Baltic Sea.
In the 1960s, commercial algae harvesting began, primarily clawed fork weed (Furcellaria lumbricalis) – an alga that forms underwater clusters with fucus. Furcellaria was harvested to produce, among other things, a gelling agent for agar. However, when estimating its underwater stocks, errors were made repeatedly, and within a few years, perhaps as much as half the population was lost. Bladderwrack disappeared along with it.
