Open access publications in the SLU publication database

The impact of the pulp mill Södra Cell Värö on fish populations has been monitored since 1983 by trawl surveys in the area where waste water is discharged. Corresponding studies have been conducted in an undisturbed reference area.

The catch is mainly dominated by young individuals of several cod (Gadidae) and flatfish (Pleuronectidae) species. The most common species in the fishery is dab (Limanda limanda) and whiting (Merlangius merlangus). Several species have shown increasing catches in recent years, especially in the recipient area. Greater weever (Trachinus draco), scald fish (Arnoglossus laterna) and black goby (Gobius niger) are species that has increased in both areas. Haddock (Melanogrammus aeglefinus), brill (Scophthalmus rhombus) and common dragonet (Callionymus lyra) has increased in the recipient area, but no trend has been observed on the reference area. Plaice (Pleuronectes platessa) and cod (Gadus morhua), however, had no trend in the recipient but decreases in the reference area. Since the beginning of the survey period, species diversity in the catch increased in both the recipient and the reference area. Based on the studies, no clear negative effect on fish can be identified due to Södra Cell Värö’s emissions.

Upstream migration of young eels (Anguilla anguilla) in the river Viskan has been documented annually by means of traps in the river mouth. The migration has been very small in the last 20 years. A strong decline has occurred since the beginning of sampling in the late 1970's and in 2011 the hitherto lowest number of eels was caught. The decline has followed the trends seen elsewhere in Europe (ICES, 2009) and does probably not depend on the activities of Södra Cell Värö.

To investigate the bottom conditions in the area close to the discharge tube, this area has been filmed every fall with an ROV. The seabed adjacent to the tube showed slight signs of hypoxia in this year’s filming.