Effects of Paddlewheel Aeration on Water Quality in Crawfish Ponds

ABSTRACT

Six experimental ponds (1.8–2.2 ha each) were planted with rice Oryza sativa in August as forage for red swamp crawfish, Procambarus clarkii, and flooded in October. From late October through May, three ponds were aerated nightly for 10 hours (2200–0800 hours) with two 2.2-KW (3 hp) paddlewheel aerators per pond. The other three ponds were not mechanically aerated. Dissolved oxygen (DO) less than 3 mg/L in non-aerated ponds occurred four to five times more frequently than in aerated ponds. Chlorophyll a, biochemical oxygen demand, turbidity, nitrite, and total ammonia were significantly higher in aerated ponds. The DO, free carbon dioxide, total ammonia-nitrogen, and nitrite-nitrogen were within acceptable levels for crawfish in both aerated and non-aerated ponds. Mean crawfish harvest from aerated ponds (2,300 kg/ha) did not differ from non-aerated ponds (2,396 kg/ha). Paddlewheel aerators effectively mixed and circulated pond water but mechanical aeration was not effective in increasing crawfish yield in ponds planted with rice in late summer.

KEYWORDS:

• Red swamp crawfish
• Procambarus clarkii
• aeration
• water quality