Nippon Suisan Gakkaishi 73 (6), 1065-1073 (2007)

The extent of impact of organic loads from fish farming on chemical characteristics of sediment and macrobenthos communities in the central fish farming area in Tanabe Bay

TAKASHI UEDEa*

Fisheries Farming Laboratory, Fisheries Experimental Station, Wakayama Research Center of Agriculture, Forestry and Fisheries, Tanabe, Wakayama 646-0058, Japan

The extent of impact of organic loads from fish farming on chemical characteristics of the sediment and macrobenthos communities was investigated in the central fish farming area in Tanabe Bay. There were no diffserences in concentrations of AVS, TOC and TN in the sediment and macrobenthic indices regarding distance from fish cages. From these results, the impact of organic loads from fish farming on AVS, TOC, TN and macrobenthos communities is slight. In contrast, decrease in concentrations of TP, and increases in C/P and N/P ratios in the sediment were observed as the distance from the fish cages increased. The increase in TP closer to the fish cages results from the accumulation of Calcium-bound phosphorus originating from feeds of cultured fishes and their feces. From these results, the extent of impact of organic loads concerning the concentrations of TOC and TP in the sediment is within 100 to 200 m from the fish cages.


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