Emergency Aeration of Fish Ponds

Abstract

Dissolved oxygen (DO) concentrations were depressed in 0.57-hectare fish ponds through algicide treatment and the effectiveness of different techniques of emergency aeration was compared. The most effective device for emergency aeration was a paddlewheel aerator powered by a tractor. A tractor-powered Crisafulli pump with a discharge capacity of 18.9 m3/minute was also a relatively effective aeration device when used either to spray DO-deficient water into the air and back into the pond or to pump fresh, oxygenated water from another pond into the one with low DO concentration. A lower capacity Rainmaster pump (3.8 m3/minute) was much less effective than the Crisafulli pump when used to discharge oxygenated water into a DO-depleted pond. Neither of the pumps raised DO concentrations appreciably when used to circulate DO-deficient water in ponds. Three sizes (0.25, 2.2, and 3.7 kilowatts) of spray-type surface aerators failed to appreciably increase DO concentrations.