576 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [38] 



III. — Conclusion. 



Facility with which brooks can be stocked with trout; given the possibility of 

 receiving from a distance, by mail, einbryonated eggs: 



a. Selection of a <;ood spring, even if it should be small. 



b. Treatment of the iish after their arrival. 

 Exhortation to make experiments on a small scale. 



B. 

 I. — Introduction. 



1. The- growing depopulation of our waters, and the causes of this phenomenon: 



a. Voracious fish. 



b. Many streams have become unable to maintain iish alive, owing to industrial 



and mercantile establishments, and to the lack of spawning places, and of 

 suitable places where the fish can live. 



2. Desirability of using for the raising of hsh any waters which may still be adapted 



to the purpose. 



3. Trout are best adapted to this purpose. 



4. Artificial raising is the bes-t means. 



5. The artificial raising of fish is a German invention (invented by the Hanoverian 



Jacobi in 1758; first published, 1763-64). After it had fallen into oblivion 

 it was invented anew by a fisherman of the Vosges, Remy, in 1849, and prac- 

 ticed on a large scale at the establishment of Huningcn, in Alsace, which 

 passed into the hands of Germany in 1871. 



II.— Life and propagation of trout in open waters. 



1 . Waters in which trout and their kind live ; the idea that trout confine themselves 



to mountain streams is erroneous. 



2. Spawning place and season of the trout. 



3. The ovaries of the femalo empty their contents into the abdominal cavity. 



4. Structure of the egg : 



a. The yelk. 



b. Tho germ. 



c. The shell of the egg and the micropyle. 



5. Tho testicles of the male have ducts carrying : 



6. The sperm : 



a. The liquid of the sperm. 



b. Spermatic filaments. 



7. Depositing the eggs ; their fecundation by means of the male semen. 



8. Fecundation is accomplished by the entrance into the micropyle of at least one 



spermatic filament. 



9. The development of the young fish : 



a. Point from which the formation of tho body of tho young fish starts. 



b. Extension of the same and formation of tho back of tho young fish. 



c. Growth of the yelk round the germinal spot. 



d. Formation of the shape of the body of the young fish. 



e . Visibility of tho eyes by tho formation of pigment in tho eyes. 



/. Tho little fish with its umbilical sac, and its hatching from tho egg. • 

 </. The change of the embryo, which does not need any food, to a perfect little 

 iish. 



10. Conditions favorable to the normal development of the embryo: 

 a. The eggs should bo fecundated. 



/>. Tho eggs should be daily moistened with water not chemically pure. 



c. The water should be furnished with a constant supply of fresh air. 



d. Mud, which hinders the access of air, should be removed. 



e. The temperature of the water should not be too high (0.5° to 8° C.) [33°- 



46.5° F.]. Too high temperature accelerates development, while too low 

 temperature delays it. 

 /. Safety from mechanical dangers. If the eggs are bruised, malformation is 

 caused. Safety of the fish against enemies belonging to the animal kingdom. 



11. Which conditions of success are not'all found in open spawning places ; and how 



a large part of the eggs run a great risk. 



III. — The raising of trout. 



1. Tho nature of trout raising. 



2. Procuring fish for artificial fecundation : 



a. Obtaining spawning fish. 



b. Distinguishing the male from the femalo fish. 



c. Indications of tho maturity of tho spawn. 



d. The spawning of the mature female. 



e. Tho spawning of the mature male. 



