Ecosystem experiment to assess environmental impacts and recovery from freshwater cage aquaculture
Researchers at the Experimental Lakes Area (ELA) operated an experimental RainbowTrout farm (L375) from 2003-2007 (ACRDP project nos CA-01-09-001 and CA-02-09-002). For a period of 2 years prior to production, throughout production, and for 2 years after production, L375 and the control lake (L373) were closely monitored. By the fourth and fifth years of fish production, there was a substantial decrease in benthic invertebrate density and diversity along the entire 100 m transect from the fish cage, and increases in water column total phosphorus and algal production. The wild Lake Trout population in L375 responded to cage culture with improved condition, increased survival, increased reproduction, and over the 5 years of production, the population size nearly doubled. The forage fish community, which was not as closely monitored as Lake Trout, showed increased catch per unit effort for many species. The purpose of this extension to the project is to enable researchers to continue the monitoring of the recovery of those ecosystem components that showed the most response to aquaculture activities. Of these, the effects of aquaculture on sediments are currently of particular interest due to the intention of regulatory agencies to add sediment monitoring to commercial cage license conditions. The monitoring of the recovery of sediments under the ELA farm will provide a valuable opportunity to measure the rate of removal of waste material through assimilative processes.
2010 - 2013
Central Canada: Great Lakes, St. Lawrence Freshwater Drainage Basin
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