Bladder Wrack (Fucus vesiculosus, sv. Blåstång) and the new Fucus radicans has been selected and investigated for its sensitivity for the discharge of poisonous substrates and eutrophication of the coastal and shallow waters in the Baltic Region. The Fucus areas are important for the marine life because they are the habitats for feeding, sheltering and breeding for the small animal population that in turn are important for other parts of the ecosystem. The Fucus coverage and spreading at various depths has been investigated since 2008 in the shallow water region between Gävle and Hudiksvall.
The brown algae family Fucus is an important indicator in the surveillance of the sublittoral zone extending from shore and out to greater depth. The result from the investigations is that there has been a reduction of Bladder Wrack by up to 50% in some areas and a total collapse in some areas. In areas of collapse little or no re-establishment has been seen. In addition, the normal depth for Bladder Wrack growth is between 3 m down to 6 m. The study has shown that the depth at which the Fucus grows has decreased over time by one meter.
A negative consequence of the reduction in Fucus along the Swedish Coast is the effect on the local fishing industry where a substantial reduction has been seen. There has been a reduction in the spawn from several of the fish species in the investigate bay areas, notably pike, perch and minnow.
References: “Vegetationsklädda bottnar i Gävleborgs läns kustvatten” Report 2011:15 and “Fiskyngel i Långvind och Harkskär sommaren 2009, Report 2010:8 by the County Administrative Board of Gävleborg. The doctoral thesis “PHYSIOLOGICAL ADAPTATIONS IN TWO ECOTYPES OF FUCUS VESICULOSUS AND IN FUCUS RADICANS WITH FOCUS ON SALINITY” by Anna Maria Gylle is available from the Department of Natural Sciences, Mid Sweden University.