ARTIFICIAL PROPAGATION OF FISHES 



591 



U. &. Bureau of fisheries 

 Stocking a stream with young fish which have been grown in a hatchery. 



that are to be returned to the water. The use of barbless hooks 

 in fishing in streams containing undersized fish is a sportsmanlike 

 way of allowing the small ones to get off unharmed. 



Artificial propagation of fishes. Many fish hatcheries, both 

 government and state, are engaged in artificially fertilizing millions 

 of fish eggs of various species, and protecting the young fry until 

 they are of such size that they can take care of themselves, when 

 they are placed in ponds or streams. For artificial fertilization 

 the ripe eggs from a female are first squeezed out into a pan of 

 water ; in a similar manner the milt or sperm cells are obtained, 

 and poured over the eggs. After the eggs are thus fertilized, they 

 are placed in receptacles supplied with running water and left to 

 develop under favorable conditions. Shortly after the egg has 

 segmented (divided into many cells) the embryo may be seen 

 developing on one side of the egg. The rest of the egg is made 

 up of food or yolk, and when the baby fish hatches it has the yolk 

 attached to its ventral surface for some time. Eventually the food 

 is absorbed into the body of the fish. The young fry are kept under 



