48 



FISH HATCHERY MANAGEMENT 



DRAIN PIPE 



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CATCH BASIN 



CREEN 



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Figure 21. Pond outlet with catch basin. (Source: Davis 1953) 



The soil type is extremely important; clay soil or subsoil is best. Seepage 

 tests at the pond sites are highly desirable. Seepage loss is not as important 

 in intensive salmon or trout culture where abundant quantities of water 

 flow through the pond, but is important in warmwater fish culture where 

 circulating water flows are not required. 



Pond banks must be stable and well drained, because heavy tractors and 

 feed trucks must have access to the ponds preferably along gravelled road- 

 ways. Cement or transite material is best for water supply lines and drain 

 lines. 



CAGE CULTURE 



There is growing interest in cage culture of warmwater species such as cat- 

 fish. This involves rearing fish in small enclosures built of wire or plastic 

 netting stretched over a frame. The cages are attached in series to floating 

 platforms and anchored in rivers, lakes, and ponds or in protected areas 

 along coastal shores (Figure 23). Water currents and wind action carry 



