Dolphins The cousin porpoise, which is less than two meters long, now visits Finnish waters occasionally and is endangered in the entire Baltic Sea.
Even a hundred years ago, however, Polski was a common summer guest on all the coasts of Finland. It became clear to researchers who were looking for observations of the marine mammal in old journals.
Down university researchers analyzed all porpoise sightings from Finnish Finnish and Swedish newspapers and magazines digitized by the National Library from the early 19th century to the 1970s.
When the repetitions of the same observation were eliminated, more than 400 observations were obtained, in which approximately 500 individuals appeared.
In the 19th century and the beginning of the 20th century, porpoises were found, especially in the summer, from all our coasts, from the bottom of the Gulf of Finland to the Red Sea.
Many times the animals were just noted, but it was also common to catch them in fishing nets or to kill them by shooting or clubbing them.
Back in the 1930s, there were plenty of observations, but in the 1940s they collapsed, researchers say Boreal Environment Ressearch in the journal.
Apparently already at that time, the decline of the porpoise population was visible in our waters, which is estimated to have started in the middle of the 20th century in the entire Baltic Sea.
Round is the only whale that lives permanently in the Baltic Sea. Today, only about 500 individuals belong to its Baltic stock.
The reduction of the stock after the early decades of the 20th century was probably influenced by killing, severe ice winters in the 1940s, for example, and environmental toxins that entered the sea in the 1960s and 1970s.