The grey seals in the Baltic Sea compete for fish with the fishing industry. The seals locally eat about the same quantities of cod, common whitefish, salmon, sea trout and eel as those taken by fishermen. This is the conclusion from research carried out at the University of Gothenburg, Sweden.
Competing with the fishing industry
The grey seals in the Baltic Sea eat largely the same species and the same sizes of fish as those taken by the fishing industry. So even if the amount of fish eaten by seals is small relative to the total amount of fish caught in the Baltic Sea, the seals' dietary habits may have a major impact on the local availability of fish in the areas where they are common.
"If you compare the estimated consumption of fish by grey seals in their main range in Sweden, which is north of the Kalmar Sound, it is of the same order of magnitude as the total catch taken by Swedish professional and leisure fishermen in the same area", says scientist Karl Lundstrm.
Increasing population of seals
The grey seal was common at the beginning of the 20th century, but was hard hit by hunting and by environmental toxins, and only a remnant remained in the 1970s. However, the seal population has grown continuously since the middle of the 1980s, and this has led conflicts with the fishing industry.
"The conflict has mainly centred on the way in which seals eat from and destroy fishing gear, but as the number of seals has increased the possible competition for food resources has come into focus", says Karl Lundstrm.
Study of dietary habits
The scientists have studied the dietary habits of the seals in order to understand the role they play on the ecosystem, and how they influence the surroundings. This has been done not only by investigating prey remains in the digestive tracts of the seals but also by analysing the composition of fatty acids in their blubber. The fatty acid c
|Contact: Karl Lundstrm|
University of Gothenburg