DIFFICULTIES IN FISH CULTURE. 363 



refuse to take liver or any other of the ordinary foods available at a station, 

 and heavy mortality may result through starvation. Such a case was 

 observed among the brown trout at one of the New York hatcheries. Liver 

 emulsion was persistently refused and a great loss of fry was imminent. 

 In this emergency some fresh water shrimp were crushed through a sieve 

 and the juices were introduced into the fry troughs. Apparently this was 

 preciselv what the little trout desired. They began to feed almost at once, 

 and the trouble was practically overcome. The juice of snails living in 

 trout waters might also serve a similar purpose when the ordinary food is 

 refused. 



Transportation Losses 



Loss of Eggs. There is no doubt that in many cases fish eggs are killed 

 in transportation because of inherent weakness derived from the females 

 which furnished them; but serious losses occur also with good eggs from 

 various causes. Sudden changes of temperature not properly provided 

 against destroy many eggs or injure them so badly that the}^ develop weak 

 embryos or none at all. Improper packing material is responsible for 

 heavy mortality. Clean soft moss seems to give the best results. Leaves 

 are not suitable and should not be employed. The egg-tray with a Canton 

 flannel bottom is very sat isf actor y. 



Shock from concussion is a frequent source of trouble. In a storm on 

 one of the lakes several entire cases of whitensh eggs were destroyed. 



Insufficiency of ice in the shipping case, and delays in delivering are 

 often followed by severe losses of eggs. 



Loss of Fish. Many thousands of fish are killed annually in trans- 

 portation or as a result of injuries received in transit from one cause or 

 another. Too much or too little aeration of water in the receptacles often 

 proves fatal. Innumerable fry have been destroyed by "dipping" even 

 although with the best intentions. Overcrowding in the cans is responsible 

 for great losses. Poisonous substances accidentally mingled with the water 

 often cause severe mortality. Danger and death often lurk in the fish can 

 unless every precaution to insure cleanliness and purity is rigidly observed. 

 Poison may come from some ingredient of paint or solder; even the water 



