Focus on spawning and hatching channel catfish: research report

摘要

Ozone itself is extremely toxic to fish in concentrations as low as 0.02 mg/l. However, the instability of the ozone molecule results in rapid reaction rates and a short half-life, which is largely temperature and pH dependent. In flow-through facilities containing salmon, ozone is used to disinfect and sterilize water supplies, which inactivates water-borne pathogens thus reducing disease. In recirculating systems, ozone is used to oxidize dissolved organic compounds and improve mechanical and biological filtration efficiency. Brazil and Wolters (2002) studied the use of ozonation in hatching channel catfish eggs and in rearing fry and small fingerlings. They felt that ozonation could be used to pretreat surface and ground water flowing through hatcheries that rear channel catfish as practiced in salmon hatcheries. The researchers further noted that water used in hatcheries in the Mississippi Delta can be highly colored from humic compounds if drawn from deep aquifers or can harbor fish pathogens if drawn from near the surface. During incubation and early rearing, channel catfish eggs and fry are maintained in high numbers in hatchery tanks, which significantly increases oxygen requirements and reduces water quality. Brazil and Wolters conducted a series of trials to examine the impact of ozonated hatchery water on hatching rates and fry and fingerling growth.