[39] 



FISH CULTURE IN CENTRAL EUROPE. 577 



III. — The raising of trout — Continued. 



2. Procuring fish for artificial fecundation — Continued. 

 /. Different methods of fecundation (dry and moist). 



q. Counting the eggs by means of measuring glasses ; and placing them in the 

 hatching troughs. 



3. Necessary conditions for placing a hatching trough: 



a. A hatching trough may be placed anywhere where there is a current of not 



too warm water, which may be conducted to a place secure against freezing. 



b. Water of ponds, rivers, and springs may be used, each haviug its peculiar ad- 



vantage. 



c. Chemical purification of the water, and freeing it from injurious matter, is 



indispensable. 



d. Cleaning the water from mud may be effected by means of clearing basins or 



by filtration. Arrangement of a small sand-filter. 



c. It is desirable that tho water should fall into the hatching troughs from a cer- 

 tain height, thus producing air. 



/. A space protected against frost may bo arranged by means of a very simple 

 apparatus, as a smaii wooden shed covered with substances which are non- 

 conductors of heat, such as reeds, sti-aw, sawdust, etc. 



(j. The pipes through which tho water is conveyed should be so arranged that 

 they can easily be cleaned. 



4. A good hatching trough should be : 



a. Of durable material. 



b. Easy to handle. 



c. Easy to clean. 



d. Well protected against the enemies of fish. 



e. Should have room for a suitable quantity of eggs on a small bottom. 



/. Should be so arranged as to render easy tho care and management of the 

 eggs. 



5. All these requisites are possessed by Max von dem Borne's California trough : 



a. A description and demonstration of the trough and its accessory apparatus. 



b. Showing the disadvantage of placing the eggs on a bed of sand. 

 G. Care of tho eggs and the young fry : 



a. Necessity of daily visits to the apparatus ; special attention during rain-storms 



and snow-fall. 



b. Treatment of the eggs during the first stage. 



c. Removing every day the dead fish, to prevent the formation of fungus. 



d. Removing all sediment. 



e. How to recognize tho approach of the hatching by means of tho points of the 



eyes which become visible. 

 /. Keeping the hatched embryos cleau. 



7. Placing tho young fry iu the waters where they arc to be raised : 



a. Proper time for transporting the fry. 



b. The brook for the young fry, aud its character. 



c. Transporting the young fry' to the places where they are to be raised. 



d. Cans for transporting them. 



8. Some brief hints as to the management of trout ponds. 



9. Stocking with trout such waters as are adapted to tho purpose, but where no 



trout are found : 



a. Various methods of stocking with grown fish, young fry, and with e^s • 



hatching of the same near the waters which are to be stocked. 



b. The last-mentioned method to be preferred; accustoming the fish to the water 



in which they are to live. 



c. Choico of a good spring for embryonated eggs ; a spring which has been tried 



and found to answer the purpose, even if far away, is to be preferred to one 

 which has not been tried. 



d. Facility of sending eggs by mail. 



c. Treatment of tho eggs, Vhen they have arrived at destination, iu tho hatching 

 troughs. ° 



10. Management of trout ponds; their character : 



a. If there is only one pond, it can be used only as a growing pond. 



b. If there are at least three ponds, young fish may be raised in them. 



c. Hatching ponds, raising ponds, growing ponds. 



d. The food of trout in ponds. 



11. Growth of the trout : 



a. The growth of trout is possible wherever there is suitable food. 



b. Growing basins for trout: conditions of soil, abundant supply of suitable water* 



the proper control of this supply. 



c. The growth of the trout depends on ample food, and a limited space for mov- 



ing about. 



S. Mis. 90 37 



