ESTONIA
PĂľlula Fish Rearing Centre monitors and stocks salmon in Estonia
Securing the future of wild salmon Estonia has a salmon ďŹ shery in the Baltic Sea, where catches though small have stayed fairly stable hovering from ďŹ ve to seven tonnes between 2012 and 2016. The ďŹ shery is based largely on restocking efforts that are carried out at the PĂľlula Fish Rearing Centre, which since 2014 has been part of the State Forest Management Centre. The facility has released about ďŹ ve million juveniles, four ďŹ fths of which were salmon, since 1997.
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he Pþlula Fish Rearing Centre was established in 1994 to rear and replenish Estonia’s stocks of salmon. Since then the facility has added the breeding and release of sea trout (2001) and since 2016 has begun experimenting with producing whitefish and grayling. Between 2001 and 2005 brown trout were also bred and released into Estonian rivers. Salmon, an iconic species in the Baltic Sea region, has historically been present
in 12 Estonian rivers, but dam building, destruction of habitats including suitable breeding grounds, and overfishing are among the reasons behind the need for restocking efforts. Ms Kaire Martin, Director General in the Ministry of Environment adds that over the years different activities have been carried out to improve conditions for salmon. Since 2013, for example, there is a legal requirement to grant free migration both upstream
Kaire Martin, Director General in the Ministry of Environment 44
and downstream to salmonids in salmonid rivers. As a consequence, almost 90 fish passages have been constructed of which 70 have been for salmonids. By recovering salmon habitats and opening these migration routes not only do salmon populations become stronger, she says, but many other fish and aquatic species benefit too.
Self-sustaining wild salmon populations in three rivers The main migratory species in Estonia are salmon, sea trout, river lamprey, and whitefish. Atlantic sturgeon too used to be found in the Narva river, but is now extinct largely because of the construction of dams which prevented access to or destroyed spawning areas. Atlantic salmon spawns in 12 rivers of which three have native salmon populations and where no releases are carried out, seven have a mix of native populations and fish bred at the hatchery, while fish in two rivers are based almost exclusively on releases. The stocks in the different Estonian rivers are genetically similar to each other, except for the Pärnu river stock. Estonian restocking efforts in the Gulf of Finland, where 11 of the rivers discharge, are based on spawners from the Kunda river, which is one of the local wild stocks, while the Pärnu river, which discharges
into the Gulf of Riga, is stocked with material from the Daugava river in Latvia. The Pärnu is the biggest river system in Estonia with a catchment area of about 7,000 sq. km. Most of this is free, but the Sindi dam some 14 km from the sea currently blocks the lower reaches of the river. Further upstream are two other dams, but good fish passes there ensure free passage.
Salmon parr density shows upward trend The extent of available salmon spawning areas in the different rivers today amounts to some 78 ha of a total potential of about 190 ha. The construction of fish passes has over the years gradually been adding to the available spawning area, but there are still significant areas that are closed, in particular on two of the rivers that host pure wild salmon populations. The institute monitors the results of breeding and release activities by electrofishing to estimate parr density at some 70-100 sites in about 50 rivers annually, an effort that was initiated in 1974. The sites chosen are the same each year allowing comparisons to be made from one year to the next. The parr density is calculated per 100 sq. m of river bed. This is a standard method throughout the Baltic Sea and enables therefore also international comparisons. In general, parr density has been increasing over the last decade, says Dr Martin
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