title: Evaluation of long-term biomarker data from perch (Perca fluviatilis) in the Baltic Sea suggests increasing exposure to environmental pollutants.
abstract: Since 1988, biomarkers in female perch (Perca fluviatilis) have been analyzed at a reference site on the Swedish Baltic coast. Strong time trends toward increasing hepatic ethoxyresorufin-O-deethylase (EROD) activity and reduced gonadosomatic index (GSI) have been observed. This could be caused by pollutants as well as other factors, such as increasing water temperature or reduced mean age of sampled fish. Correlation analyses were used to find the most probable explanation for the time trends. The time trends were still significant for EROD (p < 0.001) and GSI (p < 0.001) when the correlations were controlled for age. Furthermore, increasing water temperature could not explain the time trends. Exposure to pollutants through runoff from land was found to be probable, because mean flow rate in a nearby river during the last 20 d before sampling correlated to EROD activity (p < 0.01). In addition, the sum of EROD activities during the life time of the perch (ERODlife) correlated significantly with GSI (p < 0.001). This suggests that perch exposed to more EROD-inducing chemicals during their lifetime have reduced or delayed gonad development. The time trend in GSI and the correlation between ERODlife and GSI were supported by data from a site in the Bothnian Bay (northern Baltic Sea; p < 0.05). The results indicate that increased rain fall (climate change) can affect the distribution and bioavailability of chemicals in coastal areas. The link between EROD and gonad size supports the common assumption that biochemical biomarkers can act as early warning signals for effects on higher levels, which commonly is difficult to show. The significant results can probably be attributed to the unique 20-year data set.
authors.affiliation: Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Gothenburg, Sweden. niklas.hanson@dpes.gu.se
authors.forename: Niklas
authors.initials: N
authors.lastname: Hanson
authors.forename: Lars
authors.initials: L
authors.lastname: Förlin
authors.forename: Ake
authors.initials: A
authors.lastname: Larsson
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D049628:Body Size; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004781:Environmental Exposure; D006066:Gonads / Q000187:drug effects; D009929:Organ Size / Q000187:drug effects; D010471:Perches; D012623:Seawater; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1