MedicalResearch.com Interview with: Dr. Norbert Kamjunke Helmholtz-Centre for Environmental Research UFZ Department of River Ecology Magdeburg, Germany  MedicalResearch.com: What is the background for this study? Response: Aquacultures are of great importance worldwide but pollute pristine headwater streams, lakes, and estuaries. Chilean salmon production is economically important, contributing ~25% of the worldwide salmon yield (Chile ranks second of the world’s salmon-producing countries). Salmon farming has continuously increased in recent decades; the annual salmonid production in Chile was 820,000 tons in 2012, representing a value of 4.9 billion USD (32% of the total worldwide value of salmonid production). Small salmon are reared in land-based aquacultures supplied with stream water, whereas mid-sized fish are grown in cages in lakes and adult fish in cages along the coast. The effluents from land-based aquaculture pollute pristine streams with nutrients, antibiotics and organic carbon, resulting in oxygen depletion and negative consequences for the abundance and biodiversity of stream organisms. While aquacultures have recently started to remove suspended matter from waste water using sedimentation basins and rotating drum filters, dissolved components are still discharged untreated. Nutrients and dissolved organic matter (DOM) originating from the leaching of remaining food pellets, fish faeces and fish excretions are major components released by aquacultures. One aquaculture in northern Patagonia was estimated to release DOM amounting to 21% of the carbon applied as feed and 76% of the annual fish production. (more…)