Baltic fish face more pollution today than two decades ago.
Hanson, N, L Forlin and A Larsson. 2008. Evaluation of long term biomarker data from perch (Perca fluviatilis) in the Baltic Sea suggest increasing exposure to environmental pollutants. Environmental Toxicology and Chemistry doi:10.1897/08-259.1.
For 20 years, researchers have analyzed an array of biomarkers in female fish in an effort to identify trends in pollution exposure over time. The authors found strong time trends in two common biomarkers. Levels of the enzyme hepatic ethoxyresorufin-O-deethylase (EROD) have been increasing, whereas the gongal somatic index (GSI) of the fish has been decreasing.
The pollution exposure correlated with water runoff from land, suggesting that exposure to pollutants from surrounding land areas may be a cause for these trends in fish and pollution. Elevated levels of EROD suggest exposures to pollutations that, in this case, appear to reduce gonad size and might affect reproductive output for the population.