Is COVID-19 driven shutdown of Danish fur industries alarming signal for the Baltic Sea eutrophication?

Mikko Jokinen,
Environmental Director Emeritus,
City of Turku, Finland

Long Term Co-Chair in UBC Sustainable Cities Commission

Nutrient load into the Baltic Sea has slowly turned to decrease, thanks to many political and practical measures taken by EU and Baltic Sea states during the last three decades.

Despite of this positive development the state of the sea is still alarming. Annually more than 30 000 tons of anthropogenic phosphorus ends into the sea, increasing eutrophication and the risk of harmful algae blooming. Sustainable phosphorus inflow level into the Baltic sea is estimated to be at least 10 000 tons less than it receives today. Consequently, we have still a lot of work to do.

Beside the high phosphorus load the Sea faces another increasing problem: A strong decline in randomly incoming water pulses from the North Sea through the Danish straits into the Baltic Sea. During the last two decades pulses have strongly weakened and they are bringing less salted and oxygen rich water into the Baltic Sea compared to the time before 1990´s. Reason for this is not yet fully understood. Present trend started soon after the construction of new bridges and other structures in the Danish straits were completed, which, together with the several consequences of the climate change, may (partly) explain the phenomenon.

Anyway, it is clear, that the biological productivity of the sea has increased due to the rising nutrient levels. This has led e.g., to growth of Baltic fish populations, and also such bird and mammal populations, who use fish stocks as a main food source. 

Commercial fishing removes nutrients from the sea

Main, and practically the only notable way to remove nutrients nowadays from the Baltic ecosystem is commercial fishing of cod, herring, and sprat. In some coastal areas seals and a few fish-eating seabirds play an important role as fish stock utilizers, but they do not remove phosphorus and nitrogen from the sea. Great cormorant is the only exception. It breeds in big colonies and when they locate on non-rocky islands, main part of the nutrients in their excrement will storage into the soil of island. Big breeding colony can remove hundreds of kilos of phosphorus and nitrogen from the water ecosystem every year. This positive effect is not normally recognized, because extra nitrogen is at the same time killing nesting threes and making the colony islands appear unaesthetic.

Commercial catch of herring and sprat has been at high level during the latest years compared to time in the beginning of the millennium. Cod populations have been reverted. They are suffering of heavy fishing pressure and poor reproduction mainly due to lower salinity in the Baltic Prober. Sprat is the main food for cod in the pelagic Baltic ecosystem, so decreasing cod numbers have allowed sprat populations to grow.

Total Baltic Sea fish catch was 760 000 tons in 2018. Among the fish some 3 500 tons of the phosphorus was removed from the sea. This is remarkable amount and important for the nutrient cycling in the Baltic ecosystem. However, it corresponds only some 10 % of the annual inflow of phosphorus into the sea, so we are still far from the sustainable nutrient balance of the Baltic Sea ecosystem.

Most of the commercial catch is used as animal food. Fur industries is the main end user, fish farming the second. For instance, in Finland annual catch of 2018 was 138 000 tons, mainly herring and sprat. 95 % out of that was used as forage in fur farms, only 3% was used as human food. Part of the catch was taken to Denmark for mink food there.

Denmark has been the most important fur industry country at the Baltic Sea Region (BSR) with more than 17 million minks (compared to 1 million in Finland) still in 2020. One mink use some 60 kg of forage during its lifespan. This means that Danish minks alone eat annually more forage than the whole Baltic Sea commercial fish catch at the same time. Herring and sprat are important part of mink food and Danes have been biggest utilizer of fish forage in the BSR area, even though main part of their mink food is coming from the North Sea or Atlantic. There is a small scale fur industry also in other Baltic states, and the industry has even been growing in Poland, when Dutch and Danish companies have moved their production to Poland.

When a new form of COVID19 was found at Danish mink farms last autumn, Danish government took a quick decision to kill all minks and close all the mink farms immediately. Forage consumption of those animals has been at the level of 1 million ton a year. This means, that there will be big changes in feed fish demand in the BSR from 2021 onwards.

This rises a serious question. What will happen to the Baltic fishing and fish industry? If mink farms in Finland, Poland and other Baltic countries will share the destiny of Denmark, there will be a remarkable crash in the demand of Baltic herring and sprat. Unfortunately COVID19 is not the only threat for fur industry. Public opinion in many countries is increasingly against fur farming. This may already in near future lead to a total ban of fur farms with heavy consequences for the Baltic fishing industry as well.

Is the fish industry prepared for that kind of challenges? Can they find alternative ways to utilize sprat and herring? It is obvious, that when the demand of fish will decline also the price of the fish will decline. Consequently, it is challenging to find alternatives. Fish oil and fish flour industries are still small at BSR, they might have possibility to increase their capacity, but is it economically feasible?

Already 10 % decrease in fishing intensity would mean 350 tons more phosphorus staying in the Baltic ecosystem. Much effort is needed elsewhere to replace this cap and keep BSR on right track in nutrient management.

Epilogue

A full-length mink coat contains 40 mink pelts and represents 2,5 tons of fed, including at least 10 kg of phosphorus. It is a bit confusing to think, that mink coat wearing ladies in Asia and elsewhere are important end users in the Baltic Sea nutrient cycle. Nowadays some 5 million minks used for the women’s clothing annually are fed by the Baltic fish and remove more than 1000 tons of phosphorus from the Baltic Sea.

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