Baltic Salmon and Trout Assessment Working Group (WGBAST)

Correction (19/06/2023): authorship list revised
Correction (01/12/2023): Sections 3 and 5 updated

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 2022. Salmon in subdivision 22–31 were assessed using Bayesian methodology with a stock projection model (data up to 2022) 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.

• Since 2022 salmon commercial salmon fishing has been restricted to Bothnian sea and Gulf of Finland.
• Only recreational salmon trolling in the Baltic Main Basin is allowed and daily bag limit is one adipose fin clipped salmon per day.
• Since the 1990s, production of wild salmon smolts has gradually increased in the Gulf of Bothnia and Gulf of Finland. For most rivers in Gulf of Bothnia smolt production is predicted to increase slightly in 2024. Long-term trends for smolt production in southern Main Basin rivers have remained stable or slightly decreasing.
• The current (2022) total wild production in all Baltic Sea rivers is over 3 million smolts, corresponding to about 79% of overall potential smolt production capacity. In addition, about 3.7 million hatchery-reared smolts were released into the Baltic Sea in 2022.
• Out of 17 analytically assessed wild salmon stocks, 7 have reached MSY level with very high certainty, especially in the northern Baltic Sea.
• In the Gulf of Finland, wild Estonian rivers show recovery. As assessed previously, most weak stocks are located in the Main Basin. Several of the rivers in this area are far below a good state and have showed a negative development in recent years.
• The exploitation of Baltic salmon in the commercial sea fisheries has been specially restricted to Bothnian Sea and Bothnian Bay area and is at a low level. Thus, most stocks (for which analytical projections are currently available) are predicted to maintain present status or recover. 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 Main Basin stocks require such measures.
• M74-related juvenile salmon mortality increased in hatching years 2016–2018, but is currently expected to remain very low in spring 2023. 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. Most alarming is the situation in Ljungan where parr densities have been low. Despite ongoing research, the reason(s) behind the deteriorating salmon health remains largely unknown.
• Positive development for sea trout in the Gulf of Finland and Baltic Sea eastern region, but many populations are still considered vulnerable. 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.