112 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



For the first few weeks after the eggs have reached the hatchery- 

 close attention must be given to prevent the growth and spread of 

 fungus throughout the tank. The eggs must be carefully hand-picked, 

 and the trays and boxes kept thoroughly cleansed from slime and other 

 impurities. If a heavy rain should wash dirt, refuse, etc., into the 

 supply reservoir and thence to the hatchery, the eggs must be cleaned 

 to prevent their smothering. No filter, i^ractical for use in a hatchery, 

 has been invented that will entirely remove injurious substances. 



To remove the egg-trays from the boxes for sorting, the binder is 

 first slipped out from the grooves and the trays taken out separately, 

 each rising to the surface as the one above it is removed. All the 

 trays are taken out of one box and placed one after another along 

 the picking-trough. The dead eggs and "ringers" — the latter not 

 appearing until in the later stages of incubation — are then picked out 

 with small metal tweezers. The eggs will turn white when dead, and 

 if allowed to remain upon the trays a fungus will soon appear upon 

 their surface and spread its growth until all the eggs within a short 

 radius are aftected; these in their turn will be smothered and become 

 fungussed in the same manner. 



When it is necessary to change the position of the eggs in order to 

 bring those at the bottom to the surface a soft feather is used, and if 

 manipulated carefully it will have no injurious effect. After the eggs 

 have been carefully sorted the trays are again placed in the hatching- 

 box. The eggs are looked over at least every three days during the 

 first five or six weeks; at the end of that time, in a water temperature 

 of from 40° to 45° F., the eye-spots will show up phiinly, and from this 

 stage to the breaking of the shell less labor need be expended in this 

 direction, for the eggs are not so susceptible to fungus, etc., as in the 

 early stages. At this period unimpregnated and imperfectly developed 

 eggs are easily distinguished and taken out at one picking, leaving 

 practically only those that will ultimately hatch as perfect fry. 



For washing the eggs when coated with sediment a large galvanized- 

 iron pan, about 2i feet long. If feet wide, and 4 inches deep, is used; 

 this is nearly filled with water and a tray floated on its surface. The 

 eggs are gently moved about with a feather, and by submerging and 

 quickly raising the tray the eggs will be left as clean as when first 

 taken. It is necessary to be very careful to give no sudden jar or 

 shock to the eggs, for up to the time the eye-spots begin to appear they 

 are very delicate and must be handled accordingly. It is better to 

 allow a small amount of dirt to remain on the egg^i than to under- 

 take washing them, which should only be done when the coating of 

 sediment becomes dangerously heavy. The boxes may be washed when 

 the trays are in the picking-trough, but to wash the trays is difficult, 

 yet very necessary in case they become covered with slime. 



The eggs may be transferred to a clean tray without serious harm 

 by placing the clean tray face downward upon the dirty one, and by a 

 quick movement reversing their positions, submerging both trays in a 



