Abstract: The energy conversion efficiency (ECE)of pond ecosystem cultivated mainly with black carp(Mylpharyngdon piceus) at Suzhou suburb during 1985-1987 is analyzed. The results show that productions of black carp, common carp and bream carp are respectively accounted for 82.49, 78.03 and 79.34% of total energy output in the ponds with net production levels of 7.5, 11.25 and 25.15t/ha. The ECE of total energy input (including solar and supplementaty energies)converted into total energy output of fish is 0.19, 0.24 and 0.31%, and that of solar radiation energy converted into gross or net primary productivity is 0.76, 0.90 and 0.96% or 0.61, 0.72 and 0.77% respectively. The ECEof net primary productivity converted into net production of filtering fishes is 4.02, 4.63 and 5.27%, and that of supplementary energy converted into net production of fishes is 12.20, 11.33 and 11.74% respectively.Among the three ponds with different net production levels, that with net production of 15t/ha is an optimd:\PDF\.pdfal one.

Key words: Black carp, Energy conversion efficiency, Pond, Ecosystem