This core indicator evaluates the status of coastal sea
areas of the Baltic Sea based on the abundance of sea trout parr in rivers
where they breed. The determination of whether Good Environmental Status
(GES) is reached is based on a comparison of the observed parr densities in
rearing habitats with the reference potential parr densities in the specified
habitats. The current evaluation assesses the status of sea trout populations using
data from 2014 and expert evaluations.
The current evaluation shows that the status reflected by
populations of sea trout is sub-GES in most Baltic Sea coastal areas. GES
is not achieved in the Bothnian Bay, the Bothnian Sea or the Gulf of Finland.
A positive development in parr densities since 2012 has been observed in
some rivers in Finland (Gulf of Finland), Estonia (Gulf of Finland) and Sweden
(Bothnian Sea), reflecting management improvements in these countries.
In the Baltic Proper, the status of sea trout
stocks is better in south-western sub-basins where the majority of stocks reach
production levels reflecting GES.
level of confidence of the assessment is moderate to high.
indicator is applicable in the rivers of all the countries bordering the Baltic Sea.
The densities of parr measured in rearing areas in rivers
reflect the abundance of the adult sea trout spawners and success of
recruitment. Adult sea trout carry out feeding migrations in the Baltic Sea
where they are top predatory fish.
Sea trout abundance is affected by commercial and
recreational fishing at sea and in rivers. The parr densities measured in
rivers are affected by migration barriers to reproduction areas and
habitat quality. Thus the indicator reflects the state of
the ecosystem as it is sensitive to river connectivity (effect of dams) and the
quality of spawning and rearing habitats.
BSAP segment and objectives
MSFD descriptor and criteria
Thriving and balanced communities of plants and animals
Viable populations of species
1.1 Species distribution1.2 Population size1.3 Population condition1.5 Habitat extent
4.3 Abundance/distribution of key trophic groups and species
D3 Commercial fish and shellfish
3.1 Level of pressure of the
fishing activity3.2 Reproductive capacity of the stock
Other relevant legislation: In some Contracting Parties of HELCOM potentially also EU Water Framework Directive
HELCOM (2015) Abundance of sea trout spawners and parr. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Core indicator report – web-based version October 2015 (pdf)
Extended core indicator report – outcome of CORESET II