HATCHERY REQUIREMENTS 53 



DISKASE CON IROl, SPFXIAL FEATLRKS 



Circular tanks and pond ^ 



Can be a problem bee ause of recirculating Controlling velocities, self-cleaning. 



v\ater and low How rates. 



Reclangular-circulation rearing ponds 



Same as abo\e. Uniform velocity throughout; relatively 



self-cleaning. Expensive construction. 



Swedish ponds 



Same as abo\ e. Self-cleaning; large surface area to depth 



ratio. Moderate velocitv control. 



Rectangular tanks and raceways 



\'er> good if tank designed properly. Relatively ine.xpensi\e construction, 



readil) adaptable to mechanization 

 (cleaning, feeding, crowding). 



Earthen ponds 



A problem because of flow patterns and Many attributes of a natural environment, 



buildup of wastes hc\m large groups of 

 production fish. 



Cage culture and pen rearing 



Difficult Inexpensive facilitv ; water readily a\ail 



able. 



