Impact of Cage Aquaculture on Water Quality Condition in Lake Maninjau, West Sumatera Indonesia

Water quality characteristic of Lake Maninjau related to the deterioration condition has been intensively reported, nevertheless research on water quality as an impact of cage aquaculture level has never been done. The aim of this research was to identify influence of cage density to water quality condition. The study was conducted at 11 stations in Lake Maninjau, by measuring 11water quality parameters at a depth of 4.5m and sediment organic content on locations that have soft substrate. Measurement periods were on June 2013, September 2013, December 2013, and March2014. Activity of cage aquaculture was distributed in all over the lake shore lines, with the highest density at 1226 units km-1. Water quality measurement indicated similar condition based on spatial patterns (degree of similarity >85%) with tendency that the increase number of cages influence several parameters including increase concentration of chemical oxygen demand (COD), total nitrogen, and ammonium; and decrease concentration of dissolved oxygen. Although statistical analysis (Test T, for variant analysis) showed only COD on low to middle level cage density and ammonium on middle to highest level cage density were significantly different (P<0.5). International Journal of Sciences: Basic and Applied Research (IJSBAR), Vol. 23, No. 1. Hal. 120-137