Herring. Photo: Pixabay

Published 2025-06-11.

This autumn, EU fisheries ministers will gather to negotiate next year's catch limits in the Baltic Sea. They are not only guided by ICES’ advice. They must also take into account the EU's Common Fisheries Policy (CFP) and the rules of the EU's multi-annual management plan for the Baltic Sea (MAP).

This year, ICES’ advice is once again at odds with both the management plan and the CFP for the two largest herring stocks in the Baltic Sea.

Violating the ‘five per cent rule’ – once again

If ministers choose to follow the ranges for total catches set out at the top of ICES' latest headline advice for these stocks, the results are as follows:

• Central Baltic herring: The catch is increased from 110,881 tonnes to 120,378 – 157,996 tonnes. The probability of the stock's spawning biomass falling below Blim is then 5.9 – 8.1 per cent. According to the ‘five per cent rule’ in the management plan (Article 4.6), this probability must not exceed 5 per cent. To meet the ‘five per cent rule”, the catches must not exceed 103,073 tonnes, according to ICES’ forecasts (see bottom of Table 2 in ICES’ advice).
• Herring in the Gulf of Bothnia: The catches are reduced from 66,446 tonnes to 55,869–62,684 tonnes. Within that range, the probability of falling below Blim is 9–10 per cent. To meet the ‘five per cent rule’, the catches must not exceed 25 560 tonnes (see bottom of Table 2 in ICES advice).

Sara Söderström. Photo: Björn Eklund

"It is remarkable that ICES' headline advice is not in line with the current regulations. The reason is that there is a discrepancy between the Commission's order to ICES and what the jointly agreed regulations state," says Sara Söderström, researcher at Stockholm University Baltic Sea Centre. 

Article 4.6 of the management plan is a kind of final ‘safety barrier’, which is supposed to prevent stocks from collapsing due to excessive fishing pressure. The Baltic's two largest herring stocks are now in such a bad state that the “five per cent rule” is relevant.  

"I hope and expect that fisheries ministers can look past ICES’ headline advice when they meet this autumn, and realise that they must stick to the level of risk that the EU has decided and actually legislated on," Sara Söderström says.

Ministers broke the rules

However, the outcome of the ministerial meeting in October is an open question. Two years ago, in 2023, the situation was quite similar. Even then, the catches in ICES’ advice exceeded the limits set out in in the management plan.

The European Commission followed the management plan and the 'five per cent rule' and proposed to stop directed herring fishing in both the central Baltic and the Gulf of Bothnia, with lower by-catch catches on both stocks. But the Council of Ministers said no, and decided in favour of continued directed fishing and relatively high catches for both stocks.

This year, the situation is not quite as dire. The herring fishery does not need to be stopped completely. But to meet the 'five per cent rule', catches will still have to be cut substantially in relation to ICES advice: by 14–35 per cent for herring in the central Baltic and 54–59 per cent for herring in the Gulf of Bothnia.

"I find it hard to imagine that the Commission will propose anything else than catches that are compatible with the management plan. They have to follow the law. It remains to be seen what catches the Council of Ministers finally will decide on," says Sara Söderström.

Failure to meet objectives

The EU's Common Fisheries Policy (CFP) establishes guiding principles for managing fisheries and fish stocks. One of the most important principles is maintaining long-term productive fish stocks with spawning stock biomasses above the Btrigger limit. At this level, stocks are considered large enough to provide the maximum sustainable yield (MSY).

In this respect too, ICES' latest catch advice is at odds with EU rules and objectives.  
If the herring stock in the central Baltic is to grow sufficiently to reach above the Btrigger, the catches in 2026 must be limited to a maximum of 18,809 tonnes, according to ICES' own forecasts. This means that the catches would need to be 84-88 per cent lower than the range indicated in ICES’ advice.

Spawning stock biomass of herring in the central Baltic Sea. (ICES)

For the herring stock in the Gulf of Bothnia, the picture is even bleaker. This stock is already so small that the target of a spawning stock biomass above Btrigger will not be reached – even if there is no fishing at all next year.

Spawning stock biomass of herring in the Gulf of Bothnia. (ICES)

Great uncertainty about the sprat

For several of the other Baltic Sea stocks, the outlook is not particularly bright either. Cod stocks in the western and eastern Baltic Sea have long since collapsed, and ICES advises zero catch for them.
The trend for sprat has been very worrying in recent years, with record low recruitment and a sharp decline in spawning biomass. However, according to ICES' forecast, recruitment will skyrocket in 2025, with a really good year class of new fish added to the stock. Therefore, ICES believes that it is possible to increase the catches by just over 20 per cent, to 176 056–230 518 tonnes.  
At the same time, ICES warns that the forecast is uncertain. In addition to the lack of accurate data on misreporting and on Russia's catches, the forecast is based on just a single acoustic survey. 

“These are important warning signals, which I hope policy makers will take on board. The sprat has had three years of very poor recruitment. Even if there is a good recruitment year this year, it does not necessarily mean that there will be a good development for the stock as a whole,” says Sara Söderström.

When cod collapsed, flatfish took over

The clearest positive trends are seen in the flatfish stocks. Plaice, dab, flounder and brill are booming both in the Baltic Sea and on the west coast. 

"It is noticeable that the fishing pressure on these species has decreased as cod fishing has virtually ceased. After the cod fishery collapsed, flatfish increased,” says Henrik Svedäng, researcher at Stockholm University Baltic Sea Centre and the Swedish Institute for the Marine Environment.

Henrik Svedäng.

The decline of Baltic cod has long been associated with the effects of eutrophication, with oxygen deficiency and a lack of bottom-dwelling small animals on the seabed, as well as with rising water temperatures as a result of climate change. However, according to Henrik Svedäng, the marked increase in the flatfish stocks suggests that bottom conditions are good enough.

"Both the western cod stock and the Kattegat cod stock would probably be very productive today if they had not been so heavily overfished in the past," he says.

"Why the eastern stock of Baltic cod has not recovered despite halted fishing and relatively good recruitment is a question that science still does not have definite answers to."

"Poor understanding of how stocks function"

Henrik Svedäng also has difficulties understanding the scientific conclusions about next year's herring catches in ICES' latest advice. According to him, it is not only the recent alarms about herring shortages along the east coast that call for significantly lower fishing pressure in the central Baltic Sea and the Gulf of Bothnia. The figures and forecasts in ICES' own tables also indicate that something is not right.

"Take the Baltic herring in the Gulf of Bothnia, for example. It's almost comical when ICES says that the fishing pressure there is good because it's below Fmsy, while the stock has declined continuously over the past 35 years," Henrik Svedäng says.

On the contrary, if fishing pressure were sustainable, the stock should be recovering even if individual growth has declined.

A similar pattern can be seen for the herring stock in the central Baltic Sea: fishing pressure is estimated to be below Fmsy, while the spawning stock biomass has long fluctuated around the minimum sustainable limit before collapse (Blim). 

"ICES are less informed about how stocks function and how productive they are than the public and politicians believe. They often do not know where they are in relation to their own developed values for what level of exploitation is sustainable in the long term," says Henrik Svedäng, and continues: 

"There is therefore a strong need for ICES to communicate the uncertainty in their own calculations and assumptions."

The role of herring in the ecosystem is overlooked

At its core, fisheries management is about so much more than just catches and individual stocks. In a species-poor sea like the Baltic, species are interconnected with each other and with the marine environment. For many years, both science and policy have been striving for a more ecosystem-based approach. But so far, it has had little practical impact on fisheries management, either politically or scientifically.

Åsa Nilsson Austin.

Åsa Nilsson Austin, a researcher at the Baltic Sea Centre, points out that the advice on which annual catch decisions are based largely treats various fish stocks as individual entities. This does not reflect reality below the surface.

"ICES’ advice should take into account the central role of herring in the Baltic marine ecosystem. For example, herring is food for cod, salmon, grey seals and porpoises. Many of these species are already in poor condition," she says.

The decline of herring stocks also affects their prey, ranging from plankton to small fish. 

"From an ecosystem perspective, the situation for herring stocks does not look good. This calls for sharply reduced catches and much greater caution in management," says Åsa Nilsson Austin.

Text: Henrik Hamrén