52 



I-ISH HAICHEKY MANAGEMENT 



Table 6. summary of rearing unit characteristics for fish hatcheries. 



TYPE 



UA 1 KR SLl'I'l.V 



I()I'(K.KA1'II^ 



Various sizes available 

 in a variety of materi- 

 als. Can be used for 

 small or large groups 

 of fish. 



Circular tanks and ponds 



Pump or high-pressure 

 gravity; low flow 

 volume. 



Level or sloped. 



Fairly restricted to one 

 size; used e.xtensively 

 with large groups of 

 production fish. 



Reitangular-circ II latum rearing ponds 

 Same as above. 



Same as above. 



Various sizes; used for 

 small or large groups 

 of fish. Larger units 

 made of concrete. 



Swedish ponds 

 Same as above. 



Same as above. 



Small tanks made with a 

 variety of materials; 

 used for small or large 

 groups of fish. Race- 

 ways generally made 

 of concrete for large 

 groups of production 

 fish. 



Rectangular tanks and raceways 



High- or low pressure 

 gravity; high flow 

 volume preferred. 



Slope preferred for 

 reaeration ol water 

 between units. 



Generally for large 

 groups of production 

 fish. 



Ear/hen ponds 

 High- or low pressure 

 gravity; high or low 

 flow volume. 



Level preferred. Consid- 

 erable area of land 

 required. 



Various net materials; 

 can be built in various 

 sizes. Generally 



smaller units than 

 raceways or ponds. 



Cage culture and pen rearing 



Lake or pond with some 

 current or protected 

 coastal or stream area. 



Protected shoreline. 



