Salmon farms contribute to growing numbers of ocean 'dead zones'

Robert J. Diaz of the Virginia Institute of Marine Science and co-author Rutger Rosenberg of the University of Gothenburg recently published research in the peer-reviewed journal Science, reporting that there are now more than 400 'dead zones' in waters around the world.

Dead zones are areas with too little oxygen to support life. The scientists blame most of the world's dead zones on pollution-fed algae, which robs the water of its oxygen. Fertilizer and sewage run-off, the burning of fossil-fuels, and waste feed and feces from open net-cage fish farms can cause nutrient loading, which leads to problematic algal blooms. 

Diaz reports that a dead zone emerged with the arrival of fish farming in Big Glory Bay, in New Zealand. After the removal of the fish farms, oxygen levels began recovering in the bay.

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Read Diaz and Rosenberg's report (membership required.)