136 FISH FAEMING I 



that it is at its normal height, then shut off the supply. Now 

 take the vessel and carefully " float " out a sufficient number 

 of eggs to fairly cover the surface of perforated zinc in nne 

 of the trays. Do not crowd the egg's. If they do not float 

 out evenly and some lie on top of the others, alter this by 

 very gently rocking the tray while the eggs still remain 

 under water; or they may be " stroked " into proper position 

 with the help of a> feather. 



Your next care is to adjust the supply of water flowing over 

 the eggs ; and in this connection I cannot do better, than take 

 as ai basis the water supply at Howietoun, as, withoiit doubt, 



RG.35. 



Fig. 37. An Egg Extractor. 

 Fig. 38. Section of Egg Extractor. 



at that establishment is the best hatchery in the kingdom- 

 There are five boxes in a line; each box holds about lo,GOO 

 eggs ; thus each series of five boxes contains, say, 80,000 eggs. 

 That number is the maximum. Over these is run not less 

 than 2 gallons of water per minute in the early stages of in- 

 cubation, increasing to 2J gallons per minute towards hatch- 

 ing time, and at actual hatching time as much as three gallons 

 per minute may be run over them with beneficial results. This 

 quantity of water is sufficient to command satisfactory incu- 

 bation of 80,000 eggs. But if only one box holds eggs, the 

 same quantity should be run over the 16,000 (or even a lesser 

 number) as over the 80,000. Keep a constant and careful eyo 

 on the water supply, and remember that from the time of 

 spawning every step towards hatching has a marked effect for 

 good or evil on the future welfare 1 of the young fish. 



