Baltic Salmon and Trout Assessment Working Group (WGBAST)

<p dir="ltr">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 advices for fisheries in 2026. Salmon in assessment units (AU) 1–4, covering subdivisions (SD) 30–31 and parts of SD 22–29, were assessed using Bayesian methodology and a stock projection model (based on data up to 2024) to evaluate the effects of different catch options on wild river stocks. In contrast, the status of wild stocks in AU 5 (eastern Main Basin) and AU 6 (Gulf of Finland, SD 32) was assessed using expert-based elicitation.</p><p dir="ltr">Section 2 of the report covers catches and other data on salmon in the sea and summarizes information affecting salmon fisheries and management. Section 3 reviews data from salmon spawning rivers, stocking statistics and health issues. Status of salmon stocks in the Baltic Sea and catch options are evaluated in Section 4. The same section also covers methodological issues of the assessment as well as sampling protocols and data needs for assessment. Section 5 presents data and assessed stock status for sea trout in the Baltic Sea.</p><p dir="ltr">· Total salmon catches have decreased continuously since the 1990s. Since 2022, commercial salmon fishing has been restricted to Gulf of Bothnia, Åland Sea, and Gulf of Finland.</p><p dir="ltr">· The production of salmon smolts gradually increased from mid-1990s to early 2010s in Gulf of Bothnia and Gulf of Finland. Production has since then levelled out. Long-term trends for smolt production in Main Basin rivers have remained relatively stable, but at a generally low level and with large inter-annual fluctuations.</p><p dir="ltr">· The current (2024) total wild salmon production in all wild Baltic Sea rivers was about 2.9 million smolts, corresponding to about 85% of overall potential smolt production capacity (3.4 million smolts). In addition, about 3.5 million hatchery-reared smolts were released into the Baltic Sea in 2024.</p><p dir="ltr">· Survival of wild post-smolts has varied between 10% and 20% since the mid-2000s, but declined to lower levels from 2020 to 2024, with the 2021 estimate being the lowest (a median of 6.0%) in the entire time-series. 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 sea survival.</p><p dir="ltr">· All of the 17 analytically assessed wild salmon stocks in AU 1-4 were likely above R_lim, and 15 were assessed to be at or above R_MSY in 2024.</p><p dir="ltr">· In the eastern Main Basin (AU 5), most salmon stocks are weak and have not responded positively to previous reductions in exploitation rate.</p><p dir="ltr">· In the Gulf of Finland (AU 6), all three wild Estonian river stocks are at or above R_MSY. One of the wild stocks was assessed to be below R_MSY in 2023, but was above in 2024.</p><p dir="ltr">· 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, differences in post-smolt survival among stocks have become increasingly evident in recent years. This is not accounted for in the assessment model, which introduces uncertainties in status evaluations and stock projections. River stocks with uncertain statuses and/or recent negative trends may therefore require additional precautionary measures. Also, 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.</p><p dir="ltr">· Following a temporary and modest increase in M74 between 2016 and 2018, this mortality factor for Baltic salmon has since returned to historically low levels. However, predicting future levels of M74 remains challenging. Recent disease outbreaks, along with observations of fish showing signs of energy depletion – leading to large numbers of dead spawners and low parr densities in some wild rivers – also raise concerns about the potential for similar events to recur.</p><p dir="ltr">· 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 and variable in others, there is little or no change in the situation for most populations’ recent years. It should, however, be remembered that many uncertainties remain. Stocks in the northern parts of 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.</p><p dir="ltr">· 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.</p>