Fishing: an important industry and a challenge

Recently, there has been a focus on the situation of fishing. Increasingly intensive fishing has affected fish stocks, and it is currently estimated that three quarters of the most important marine fishing areas in the Baltic Sea are either over-exploited or being fished to their full capacity.

Those species of fish that are particularly affected by overfishing are those with slow growth and low productivity, such as predatory fish. The Swedish list of endangered species (the ‘red list’) includes 35 species of fish, of which ten are cartilaginous fish (sharks and rays). The list also includes economically important species such as eel, dogfish, cod, coley and turbot.

The total volume of fish that can be caught, and how much each country can catch, is determined by the EU. Advice from the International Council for the Exploration of the Sea (ICES) forms the basis for negotiations.


Cod in the Baltic Sea

Not only is cod an important economic source of income, it also plays a role in the ecosystem. Researchers have been studying the situation of cod in the Baltic Sea for many years, and have noted a worrying decline in cod stocks. For example, in the eastern cod stock – the larger of the Baltic Sea’s two cod stocks – cod have now started to reproduce at much smaller sizes than before, which tends to be a symptom of a stressed stock. During the 1990s, cod were an average of just of 40 centimetres long when they started to reproduce. Today, the average length at sexual maturity has halved.

Eels

The European eel constitutes a single stock, and its distribution area spreads across large parts of Europe. The eel stock has reduced dramatically over the last thirty years, and some calculations show that the level is now just a few percent compared with thirty years ago. Since the 1970s, researchers have tried to draw attention to the worrying decline in Europe’s eel stock. However, it is only during the 21st century that the eel’s vulnerable situation has been more generally recognised by both the International Council for the Exploration of the Sea (ICES) and the European Commission.

Salmon fail to return home

The life cycle of the wild salmon involves it being born in rivers, moving to the sea where it grows, and then returning to the rivers to reproduce. Much of this reproduction occurs in the rivers of northern Sweden, and many of the salmon from these rivers then spend several years growing in the southern part of the Baltic Sea. The problem is that a large proportion of these salmon are not returning to their natal rivers. Previously, there was severe fishing pressure in the southern part of the Baltic Sea, meaning that only a fraction of the females were able to return to their natal rivers to lay roe.

The quotas for the entire Baltic Sea have now been reduced from just over 400,000 salmon a decade ago to barely 100,000 in recent years. Longline fishing with hooks is no longer permitted in either Sweden or Finland, and salmon are now caught by Swedish fisheries using salmon traps along the Norrland coast. However, Denmark, Germany, Poland, Estonia, Latvia and Lithuania continue to fish salmon in the southern Baltic Sea. Trolling and leisure fishing are also responsible for just over 10,000 salmon being caught in these waters.

In addition, the expansion of rivers for water power generation has affected the ability of salmon to reproduce. Today, there are only around 15 rivers left with fairly strong salmon stocks, mainly in the Gulf of Bothnia. However, 2017 inventories show that problems have arisen once again, and very few of the salmon that return to their natal rivers actually reach their spawning grounds. The reasons for this are not yet known.

Overfishing

It is not only cod and eel that are threatened by overfishing. Fishing for northern prawn has increased dramatically since the 1960s. Fishing of the stock in the Kattegat/Skagerrak and neighbouring parts of the Norwegian Trench is shared by Norway, Denmark and Sweden. Over the course of ten years, the northern prawn stock has shrunk by almost 40 percent. At the most recent assessment in 2015, the northern prawn was classified as ‘near-threatened’ according to the system developed by the International Union for Conservation of Nature (IUCN). Reassuringly, however, all Swedish fishing for northern prawn is now MSC-certified, which means that fishing is carried out in a sustainable manner.

Herring and Baltic herring are fished hard, but fishing is also strictly regulated. Their populations vary significantly from one year to the next, but there are no signs that these populations are declining.

These pages include factual information from havet.nu - a site run by Stockholm University, Umeå University, the University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) within the collaborative framework of the Swedish Institute for the Marine Environment, and in cooperation with the web agency Azote.

Baltic Sea Science Center

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