Baltic Salmon and Trout Assessment Working Group (WGBAST)

The Baltic Salmon and Trout Assessment Working Group (WGBAST) was mandated to assess the status of salmon in Gulf of Bothnia and Main Basin (Subdivisions 22–31), Gulf of Finland (Subdivision 32) and sea trout in Subdivisions 22–32, and to propose consequent management advice for fisheries in 2025. Salmon in Subdivision 22–31 were assessed using Bayesian methodology with a stock projection model (data up to 2023) for evaluating effects of different catch options on the wild river stocks.

Section 2 of the report covers catches and other data on salmon in the sea and summarizes information affecting the fisheries and management of salmon. Section 3 reviews data from salmon spawning rivers, stocking statistics and health issues. Status of salmon stocks in the Baltic Sea is evaluated in Section 4. The same section also covers methodological issues of assessment as well as sampling protocols and data needs for assessment. Section 5 presents data and assessed stock status for sea trout.

· Total salmon catches have decreased continuously since the 1990s. In 2022 and 2023, commercial salmon fishing has been restricted to Gulf of Bothnia, Åland Sea, and Gulf of Finland.

· In Baltic Main Basin, only recreational salmon trolling is allowed and daily bag limit is one adipose fin clipped salmon per day.

· The production of salmon smolts gradually increased from early 1990s to early 2010s in Gulf of Bothnia and Gulf of Finland. The production has since then levelled out. Long-term trends for smolt production in Main Basin rivers have remained relatively stable, but with large interannual fluctuations.

· The current (2023) total wild production in all Baltic Sea rivers is close to 3 million smolts, corresponding to about 85% of overall potential smolt production capacity. In addition, about 3.6 million hatchery-reared smolts were released into the Baltic Sea in 2023.

· Survival of wild post-smolts has varied between 10% and 20% since the mid-2000s, but declined to lower levels in 2020 and 2021, the 2021 value being the lowest (7.7%) in the entire time series. The post-smolt survival is an important factor affecting stock development, pre-fishery abundance, and fishing possibilities. It is currently not known if the recent decline reflects a temporal drop or a more persistent change in the sea survival.

· Out of 17 analytically assessed wild salmon stocks in AU 1-4, all stocks were likely above R_lim, and 15 were assessed to be at or above R_MSY in 2023.

· In the eastern Main Basin (AU 5), most salmon stocks are weak and have not responded positively to previous reductions in exploitation rate. A tendency for a positive development is, however, evident for some river stocks in recent years.

· In the Gulf of Finland (AU 6), two wild Estonian river stocks are at or above R_MSY, and one wild stock is assessed to be below R_MSY but above R_lim in 2023.

· Most stocks for which analytical projections are available are predicted to maintain present status or recover under the current, historically low exploitation rate at sea. However, due to local environmental issues, some weak stocks are not expected to recover without longer term stock-specific rebuilding measures, including fisheries restrictions in estuaries and rivers, habitat restoration and removal of potential migration obstacles. In particular, nearly all stocks in AU 5 require such measures.

· Following a temporary and modest increase in M74 in 2016-2018, this mortality factor for Baltic salmon has again returned to a historically low level. However, it is hard to predict future levels of M74. Recent disease outbreaks and fish with apparent lack of energy, resulting in large numbers of dead spawners and low parr densities in some wild rivers, is another future concern.

· Sea trout populations around the Baltic are in general considered stable and, in most areas, within safe limits. While the situation is still worrying in some places (part of assessment area South and West), and variable in others, there is little or no change in the situation for most populations in recent years. It should, however, be remembered that many uncertainties remain. Stocks in the Gulf of Bothnia are particularly weak, although spawner numbers and parr densities show signs of improvement. Populations in Lithuania and Germany remain weak, however, probably in part due to natural causes, but they are also affected by coastal fishing.

· In general, exploitation rates in most fisheries that catch sea trout in the Baltic Sea area should be reduced. This also holds for fisheries of other species where sea trout is caught as bycatch. In regions where stock status is good, existing fishing restrictions should be maintained in order to retain the present situation.