97 



box which is described in the chapter on shad hatching. 

 For shad, the mesh of the trays is a little different being 

 of heavier wire, square and twenty-two to the inch. 

 These trays, it is unnecessary to say are painted with 

 gas tar like the wood work of the troughs, and inside of 

 the boxes and all other things with which the eggs come 

 in contact. If the wires should not be, they would rust 

 and the rust would penetrate and destroy every egg that 

 touched it. The current may be caused by the natural 

 flow of the water and by artificial means such as the use 

 of a pump, and for shad and whitefish hatching, no trays 

 are absolutely necessary. The boxes may be round or 

 square and made of tin or wood. 



We have said that whitefish work up through the 

 trays and pass over the rim into the reservoirs. This is 

 the habit with whitefish and witli shad, but the salmon, 

 salmon trout and brook trout, work down into the bot- 

 tom of the boxes, and if the eggs are left in them until 

 they are completely hatched the fry must be taken out 

 when the trays are removed. There is some danger 

 connected with this peculiarity, as the little fellows until 

 the umbilical sac is absorbed, crowd together one upon 

 another at the bottom, instinctively hiding from imagin- 

 ary enemies, and will often get smothered. They can 

 be drawn out by a syphon consisting of simply a piece 

 of ordinary rubber pipe leading into a pail of water and 

 will not be injured by the operation ; or, if the fish are 

 to be left in, a tin tube pierced with fine holes is put in 

 the box and the upper end of the syphon led into that. 

 However, the tin pipe where it enters the bottom of the 

 box is usually constructed with a hole and a cork fitted 

 to it, by means of which the fry can be drawn off and 

 the box emptied. 



