Baltic Sea fisheries need regulating, say Finnish researchers
The impact of eutrophication on fish populations was one of the themes of the two-day Baltic Sea Argumenta (Itämeri Argumenta) seminar in Kotka recently. In fishing experiments at the Finnish coast, the carp family has recently taken over as the most abundant species group.
The preconditions for the Baltic herring have deteriorated because of eutrophication and lower salinity.
In the Gulf of Finland, the herring populations have been weak in several years, and they have declined in the main basin of the Baltic Sea too. According to experts, exchangeable quotas should be introduced in Baltic herring fishery. The future yield of the fish population would thus become a commodity that fishermen can buy and sell.
Changes in the Baltic Sea plankton communities have affected not only the herring and sprat populations but also the predatory fish and bird species that have suffered from scarcity of food and lower reproductivity. The changes can thereby be seen on at least four production levels of the ecosystem.
Noxious substances accumulate in herring
Even if the dioxine concentrations in Baltic herring have been decreasing for a long time, the concentrations are still so high that it has been found necessary to impose restrictions for the use of this fish. The lower growth rate of herring makes the problem worse. If it takes a longer time for the fish to reach the size consumers appreciate, it will accumulate more of the noxious substances. The growth rate of herring is affected by several factors, among them changes in the sea plankton and the sizes of the populations of herring itself and its predators.
Fisheries must be regulated
Exchangeable quotas could be introduced in herring fishery. The future yield of the fish population would thus become a commodity that fishermen can buy and sell. This would enhance the profitability of herring fisheries, and stronger economical interests could thereby promote the political process needed for the solution of the problems of the Baltic Sea. According to polls, fishermen are favourable to the idea.
In an international perspective the need of regulation in fisheries is urgent. According to estimates, the total annual amount of money lost within the EU region because of too high fishing pressure amounts to 2300 -4500 million euro. However, the regulation of fisheries must be developed in close cooperation with fishermen. Management of fish resources can be successful only if the fishermen are willing to engage themselves to the regulation systems. Certification of fish populations would further promote the process. If the consumer is willing to pay for good management of fish populations. the profitability of fisheries might increase.
Oil accidents threaten the marine ecosystem
Another theme of the seminar was shipping and accident risks. The seminar took place in Kotka, a city for which the harbour functions are of crucial importance. On the other hand, the shipping-related risks are a serious threat to nature. The Russian transito gives Finland an annual income of more than 300 million euro, but the increase of oil transports is a major risk. The management of this risk is a demanding task for Finland.
The rapidly increasing shipping-related risks are a threat to the sustainable use of the ecosystem. This year the total volume of oil transport in the Gulf of Finland amounts to some 150 million tons of oil. One third of the Russian oil export is transported through the Gulf of Finland.
Mechanical gathering of oil in the open sea is according to a new report the most efficient method to reduce the impact of an oil accident on nature. It is also of essential importance that oil accidents are prevented as far as possible. If an accident happens, the oil get quickly to shores, and there is no treatment that can completely eliminate the damage.
An additional aspect of the Gulf of Finland risk management scheme is the nuclear power plant within the region. The cooling water to the plant must stream without complications, and the recent growth of the oil transport volumes has been taken into account in the risk assessments. However, the plant has an efficient risk management capacity for oil accidents.
In addition to the probability of accidents, sea transports contribute to the eutrophication-related risks. Especially passenger ships are considerable sources of nitrogen oxide emissions. For the whole Baltic Sea their proportion is as high as 16 %. Passenger traffic is especially heavy in the Gulf of Finland. Even in this case the choices of consumers and other economic steering methods are of crucial importance for the formation of the future of our common sea.
Discussion on the Baltic Sea goes on
The seminar in Kotka was the third gathering in a series of discussions on the future of the Baltic Sea. The next discussion will take place on 9-10 April in Jokioinen. The theme will be the impacts of agriculture. An internationally oriented summary session will conclude the series in June in Helsinki. The series has been funded by the Finnish Cultural Foundation and organized by the University of Helsinki, Finnish Institute of Marine Research, Agrifood Research Finland (MTT), Finnish Environment Institute SYKE, and Åbo Akademi.