xlii EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



eggs thus secured may then be transferred to any given locality and al- 

 lowed to hatch naturally ; or else beds are artificially prepared and attended 

 until the birth of the yoang, when these are either allowed to escape into 

 the water at once, or else they are fed for a short time, and then con- 

 signed to the ponds or streams which it is desired to stock. 



All these methods are inferior in convenience as well as in economical 

 results to the fourth, which is adopted by most fish-culturists throughout 

 the world. This consists in taking up the fish when ripe, and, by suitable 

 manipulation, in pressing out eggs from the body of the female into a dish, 

 and then by repeating the operation with the male, so as to force the sem- 

 inal fluid into the same vessel. In somecases the eggs and milt are stirred 

 together in a certain amount of water ; in others, what is called the dry 

 method is adopted, a discovery usually credited to a Russian, M. Vrasski, in 

 which no water is used with the eggs, but the milt is slightly diluted with 

 water and poured upon them. By this method a much larger proportion 

 of eggs is impregnated.* The movements preliminary to this treatment 

 of the eggs taken from the living fish are also very varied. In many in- 

 stances a careful watch is kept over localities where the fish are likely to 

 spawn ; and when the experienced observer notices that the operation of 

 spawning is about to take place, he captures the usually inattentive pair 

 by means of nets or other suitably-constructed apparatus, and proceeds 

 with the work of exclusion and fertilization. This is said to be the prin- 

 cipal method by which the eggs of the salmon are obtained in Germany 

 and elsewhere for the national and private establishments, and is liable 

 to the disadvantage of great uncertainty, and to a dependence upon 

 conditions of the atmosphere and of the water that may materially 

 interfere with the general result. Most of the doings in Connection 

 with the hatching of shad are of this nature ; the seine being swept at 

 a suitable locality, and the fertile fish stripped of their eggs and milt. 

 This operation is always fatal to the shad, their delicacy of constitution 

 not enduring such rough handling with impunity. It has also been 

 adopted in some cases for salmon, having been employed by Mr. Liv- 

 ingston Stone in obtaining their eggs during the season of 1872. 



The eggs of tlie white-fish and lake-trout are usually obtained at the 

 fisheries, and the eggs after impregnation sometimes taken to great 

 distances to be hatched. (See Mr. Milner's Report.) 



A much more satisfactory and efficient method consists in inclosing the 

 fish in pens or pounds until their eggs and milt are sufficiently matured 

 to allow thejirocess of artificial fecundation to be initiated. With trout 



* Although M. Vrasski' may have been the first to actually publish this method, Seth 

 Green is said to have discovered it, keeping it a profound secret from his fellow-lish- 

 culturists, who could not understand why so much larger a percentage of Green's eggs 

 should be productive than of their own, although they followed strictly the method 

 advanced in his treatise on fish-culture. This, however, made no mention of the dry 

 process. The claim of priority in regard to the dry process has also been made in 

 behalf of Carl Vogt. (See George P. Marsh on Artificial Propagation of Fish, Burling- 

 ton, [Vt.,] 1857, p. 35.) 



