Abstract: The density of wild Black Stockfish Sebastodes fuscescens in fish cage culture zones in Ailian Bay is assessed as 0.01 ind/m2 by one non-line regression method.And the population size of these wild fish is equal to the number of cultivated fish in 5.6 floating net cages or 135 raft net cages.These wild fish may bring positive or negative ecological effects to fish farms,e.g.,these fish will compete DO with cultivated fish and provide 0.8%～1.3% of nitrogen demand for primary production in the whole bay.Besides,the wild fish may consume feed remains and produce feces.

Key words: fish cage aquaculture, Ailian Bay, stock assessment, ecological effect