This indicator evaluates the status of the Baltic Sea area based on salmon smolt production in rivers flowing into the sea, also making use of additional supporting data on numbers of adult spawners. Determination of whether the threshold value that determines good status is achieved is based on a comparison of estimated smolt production with an estimated potential smolt production capacity.
The evaluation covers the period 2011-2016, and the final result is dependent on the last year.
Key message figure 1. Status assessment results based evaluation of the indicator 'abundance of salmon spawners and smolt'. The assessment is carried out using Scale 2 HELCOM assessment units (detailed in the HELCOM Monitoring and Assessment Strategy Annex 4). Click here to access interactive maps at the HELCOM Map and Data Service: Abundance of salmon spawner and smolt.
In the Gulf of Bothnia smolt production has increased in recent years due to higher numbers of adult spawners ascending the rivers as a result of stricter management measures. Good status is achieved in 11 out of 15 rivers associated with these assessment units, and it is probable that it will be achieved in 1-2 more rivers within the next few years. In the Gulf of Finland, smolt production is low but has recently improved in mixed rivers (supporting releases are conducted parallel with natural smolt reproduction) and three Estonian rivers are evaluated as having achieved the threshold, based on expert judgment. Smolt production in rivers flowing into the Baltic Proper is low but does show some signs of improvement.
The level of confidence of the evaluation is moderate.
The indicator is applicable in all the countries bordering the Baltic Sea except Denmark Germany, and Poland.
Salmon is a long-distance migratory large predatory fish species in the Baltic Sea marine ecosystem. Salmon abundance is mainly affected by commercial fishing at sea and by barriers in rivers to reproduction areas. This indicator has a linkage to the number of adult spawners ascending the rivers and, hence, indirectly to the commercial and recreational fishing pressure at the sea and in the river. The indicator also reflects the state of the ecosystem as smolt production is dependent on river connectivity (effect of dams) and the quality of spawning habitats.
D1C2 The population abundance of the species is not adversely affected due to anthropogenic pressures, such that its long-term viability is ensured.
D4C4 Productivity of the trophic guild is not adversely affected due to anthropogenic pressures
HELCOM (2018) Abundance of salmon spawners and smolt. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Abundance of salmon spawners and smolt HELCOM core indicator 2018 (pdf)