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The Baltic Sea, the Skagerrak–Kattegat and their coasts are subject to human impacts of many different kinds. The main threats to marine biodiversity are from eutrophication and over-fishing. |
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On 1 July 2011, the responsibility for most issues related to seas, among them, eutrophication, was taken over by the Swedish Agency for Marine and Water Management (SwAM). Issues related to environmental pollutants are still in the remit of the Swedish EPA.
The Swedish Agency for Marine and Water Management
Eutrophication an over-fishing pose problems
Eutrophication is due to the over-supply of nutrients from neighbouring land regions and from the atmosphere. The increased quantities of nutrients in the water stimulate the growth of phytoplankton and bottom vegetation.
Eutrophication can cause turbid bathing water as well as overgrowth of vegetation on the shores. The decay of organic material exacerbates the natural oxygen deficiency in areas of low water turnover, such as the deeper parts of the Kattegat and the central Baltic Sea.
Over-fishing is a threat to the environment nearly everywhere in the Baltic and in the Skagerrak–Kattegat. Indeed, these waters are so intensively fished that the very future of the industry is at risk. The absence of fish can dramatically change the natural species composition of plant and animal communities.
The grey seal population status is not entirely positive. A probable reason for the poor development of the population in the southern part of the Baltic Sea is the unintentional bycatch of seals, mostly yearlings. The health of Baltic grey seals has improved in many respects. However, the frequency of intestinal ulcers is higher in animals born in the 1980s and later, compared to animals born prior to that period.
Fewer toxic pollutants
Levels of many notorious toxic pollutants have declined in recent decades. But some newer substances are being detected in increasing amounts. PCBs and dioxins, although severely restricted, are still found in such high concentrations in Baltic fish that the National Food Administration advises people to limit their intake of oily fish. However, most of the evidence suggests that the injurious effects of toxic organic pollutants are significantly lower today than they were in the 1970s.
Direct impacts on human health due to marine environmental pollution are rare. However, poisoning can occur from eating mussels containing high concentrations of toxins.
Useful links
The Information Office for the Baltic Proper (in Swedish)
The Swedish Institute for the Marine Environment
Contaminant Research – Marine Top Predators