The Spawning Ponds and their Preparation 



As the ponds in which the brood fish are kept do not contain materials suitable for the recep- 

 tion of eggs, it is necessary either to insert such substances or to transfer the fish to ponds that 

 have been prepared for the purpose. The latter course is preferable for various reasons. 



Removing Dust, Dirt, Bubbles, Etc., from the Surface of a Concrete Spawning Pond Into Which a New Supply 



of Water Has Just Been Run 



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