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Lina Nikoleris. Photo.

Lina Nikoleris

Research administrator

Lina Nikoleris. Photo.

Synthetic estrogen directly affects fish biomass and may indirectly disrupt aquatic food webs


  • Per Hallgren
  • Alice Nicolle
  • Lars-Anders Hansson
  • Christer Brönmark
  • Lina Nikoleris
  • Murtaza Hyder
  • Anders Persson

Summary, in English

Endocrine-disrupting chemicals are known to alter the fitness of individual organisms via changes in growth, behavior, and reproduction. It is largely unknown, however, whether these effects cascade through the food web and indirectly affect other, less sensitive organisms. The authors present results from a mesocosm experiment whereby the effects of the synthetic estrogen 17α-ethinylestradiol (EE2) were quantified in pelagic communities. Treatment with EE2 at a concentration of 28 ng/L had no large effects on the pelagic communities composed only of phytoplankton and zooplankton. In communities where planktivorous roach (Rutilus rutilus) were also present, however, EE2 caused a significant reduction in fish biomass. Moreover, zooplankton biomass was higher in the EE2 treatments, suggesting that zooplankton may have been released from fish predation. Hence, the direct effect of EE2 on roach may have cascaded down the food web to produce positive indirect effects on zooplankton. This result was supported in complementary foraging experiments with roach, showing reduced foraging performance after exposure to EE2. Despite the observed negative effect of EE2 on roach and the positive indirect effect on zooplankton, these effects did not cascade to phytoplankton, possibly because only copepods, but not cladocerans—the major grazers in these systems—were released from fish predation. The authors conclude that the known reproductive impairment in fish by EE2 in combination with the disturbed foraging performance observed in the present study may be a disadvantage to fish that may result in increasing abundance or biomass of prey such as zooplankton. Hence, EE2 may have consequences for both the structure and function of freshwater communities.


  • Division aquatic ecology
  • Department of Biology
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Aquatic Ecology

Publishing year







Environmental Toxicology and Chemistry





Document type

Journal article


John Wiley & Sons Inc.


  • Ecology


  • Endocrine-disrupting compounds
  • Food chain
  • Fish indices
  • Zooplankton
  • 17α-Ethinylestradiol




  • Hur hormonreceptorer uttrycks, evolverar och påverkars av miljöföroreningar i lax- och öringspopulationer

Research group

  • Aquatic Ecology


  • ISSN: 0730-7268