20 



FISH HATCHERY MANAGEMENT 



WATER SUPPLY 

 (INPUT) 



FILTER 



STERILIZE 



HEAT OR COOL 



HATCHERY 



REARING 



PONDS 



REMOVE WASTE SOLIDS 



REMOVE AMMONIA 



REMOVE CARBON DIOXIDE 



ADD OXYGEN (AERATION) 



TEMPERATURE CONTROL 



pH CONTROL 



WASTE SOLIDS DISPOSAL 

 BOD REDUCTION 



WASTE WATER 

 (EFFLUENT) 



RECONDITIONED 



WA 



ER 



Figure 7. Schematic diagram of a fish hatchery 

 water reuse system. (Modified from Larmoyeux 

 1972.) 



AMMONIA TOXICITY 



When ammonia gas dissolves in water, some of it reacts with the water to 

 produce ammonium ions, the remainder is present as un-ionized ammonia 

 (NH .). Standard analytical methods' do not distinguish the two forms, and 



The books by Claude E. Boyd and the American Pubhc Health Association et al., listed in 

 the references, give comprehensive procedures for analyzing water quality. 



