Published 29 January 2023 at 15.42
Domestic. The pike stock in the Baltic Sea has been in decline for several years. Now researchers at Sweden's Agricultural University have created a more in-depth picture of how serious the situation is, reports Ekot. The increasing prevalence of the cormorant, the litter bird, is one of the explanations, according to the study.
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Behind the study is, among others, the researcher Jens Olsson. According to him, the reduction over time has been large in areas along the Baltic Sea coast.
– The results from our study clearly show a negative development of stocks from above all the central and southern parts of the Baltic Sea. But there are local variations with positive trends in Estonia and Finland, says Olsson.
The pike is the largest predatory fish on the Baltic Sea coast, and it is important both for the ecological balance of the ecosystem and for fishing.
The pike helps to reduce the occurrence of small fish such as spiny, which in turn provides healthier bottoms.
When the pike disappears, the risk of mass occurrence of spiny and filamentous algae increases, which leads to the disappearance of coastal underwater forests.
Previous research has shown that the pike is negatively affected by several different factors. Excessive fishing pressure, loss of important habitats and increasing attacks from both seals, cormorants and spikes all contribute to declining stocks.
– The pike occurs in local stocks that are more or less isolated from each other. The reasons behind the declines can therefore vary greatly between different coastal areas, which makes it difficult to get an overall picture, says Örjan Östman, researcher at the Department of Aquatic Resources at SLU.