42 AMERICAN FISH CULTURE. 



CHAPTER in. 



TROUT BREEDING. 



IN'CUBATIOX. AND TREATMENT OF FRY. 



Hatching apparatus. French and American plans. Supply of 

 water for a given number of eggs. Hatching-house. Illustration 

 with explanations. Filterer. Troughs. Nursery. Management 

 of h'lterer. "Washing gravel for troughs. Implements. Taking 

 the spawn. Action of the female when about to spawn. Method 

 of catching the fish on the spawning-beds. Indications of the ma- 

 turity of the eggs. Manipulation. Placing the ova in the troughs. 

 Packing and transportation of eggs. Manner of taking a large 

 number of eggs for transportation from a trough. How to examine 

 them. Illustration with explanations of the appearance of ova at 

 different stages during incubation. Table showing progress of incu- 

 bation with water at different degrees of temperature. Hatching 

 out and progress in growth and activity of fry. Treatment of fry. 

 Their food, and manner of feeding them. Their disposition to 

 escape. Transferring them to the nurseries. Their admission into 

 the first pond. Transportation of fry. 



Hatching Apparatus. Since the early experiments of 

 Reniy, a great many improvements have been made in 

 hatching fish spawn. At Huningue, trays or troughs of 

 earthenware about twenty-five inches long, five inches wide, 

 and four inches deep, are used. The eggs are placed on 

 a grille, made by arranging small parallel cross-bars in a 

 wooden frame, which rests -on projections on each side of 

 the tray, a little below the surface of the water. The- bars 



