No herring were found in the experimental fishery at the Åbo Akademi research station. According to the researchers, it remains to be seen whether this is a permanent phenomenon.
Researchers at Åbo Akademi University were surprised when no herring were found in an experimental fishery in Åland last year.
According to the university, the share of bullfishes in the fish stock has generally increased slightly since 2011, especially for roach and bream.
According to Cederberg, it is difficult to determine the reasons for the lack of herring in these waters on the basis of experimental fishing. However, there are other signs that Baltic herring are not doing well.
– The lack of herring in the catch in this study should be taken into account in the monitoring of fish stocks in Åland in the coming years, says Cederberg.
Test fishing will continue.
Number of mature pike halved
The study also revealed that the proportion of sexually mature herons in the northwestern inner archipelago of Åland has decreased.
The results were compared to a similar study conducted in 2011.
According to the researchers, the lack of herring was also reflected in the diet of the herring.
However, according to Österlund, all the large walleye caught, i.e. more than 40 centimeters in length, were larger than the largest walleye caught in 2011.
– At that time, the largest walleye was 47 centimeters long, while in 2022 the two largest walleyes were over 73 centimeters long. However, compared to previous test fishing, there are no big changes in the proportion of large groupers. The growth of zander was also at a level similar to other coastal areas in Finland, says Österlund.