204 BULLETIN OF THE BUREAU OF FISHERIES. 



displacing eggs into the abdominal cavity. There is abundant evidence that present 

 fish-cultural methods cause such displacements. They may be occasioned by dipping 

 the fish head first into a scoop net, which causes considerable flopping by the fish; or 

 by grasping the fisii oy the tail and holding her head dowTiward until her struggles 

 cease. If the fish is ripe, or partly ripe, the mass of eggs sags visibly toward the head, 

 and it would seem inevitable that any free eggs would settle into the forward end of 

 the abdominal cavity outside of the ova-containing membrane. It is, however, after 

 the stripping process has begun that the danger of displacement is greatest, and par- 

 ticularly after some eggs have been expressed and the tense condition of the supporting 

 abdominal wall is relaxed. It is largely due to displacement that the repeated strip- 

 ping process fails to secure all of the ripe eggs, and even should the fish subsequently 

 emit retained eggs, it is manifestly impossible for her to rid herself of displaced eggs. 



Another disadvantage from which the fish may suffer is rupture of the membranes 

 and injury to the ovaries by forcible pressure, so that the eggs falling into the abdominal 

 cavity are not secured. The ovary thus injured may not recover its natural function 

 and may thereby become sterile. 



I have dissected various salmonids which have had deformed or distorted ovaries 

 and others with postnuptial reduced ovaries containing hardened eggs of the previous 

 or some preceding season, and have observed several instances of rainbow trout which 

 had been stripped some months previously, containing masses of collapsed eggs adhering 

 to each other, the viscera and abdominal walls, and others more recently stripped, in 

 which the ovaries still contained eggs, in follicles, more or less crushed, and in one 

 instance of which the posterior end of the ovary still containing eggs had been broken 

 off and was loose in the abdominal cavity. Several samples of ruptured ovaries have 

 been observed. In one example of landlocked salmon, several eggs had been pressed 

 into the under side of the lobe of the liver so that they showed through on the outside. 

 These facts can be ascribed to nothing except forcible attempts to strip the fish. 



Some of these fish were artificially reared trout from a hatchery whence had come 

 a complaint that the trout were yielding fewer eggs than the normal yield, and con- 

 cerning which the suggestion was offered that the deterioration was due to inbreeding. 



It is a common practice to begin the stripping pressure well forward and to repeat 

 the movement until all eggs possible have been squeezed out, the last frequently being 

 accompanied by fecal matter, mucus, and blood. This process is not only liable to 

 injure the ovaries and membranes, but to express unripe eggs, impossible of fertilization. 

 In fact, all of the eggs are never secured and some are retained and apparently are not 

 subsequently .naturally extruded. 



In A Manual of Fish-Culture, Charles G. Atkins (1900, p. 35) thus describes the 

 process of taking eggs from the Atlantic salmon : 



The spawTitaker clad in waterproof clothing and wearing woolen mittens, sits on a stool or box, 

 and on a box in front of him is a clean tin pan holding about 10 quarts, which has been rinsed and 

 emptied, but not wiped out. A female salmon is dipped up from one of the floating pens and brought 

 to the operator, who seizes her by the tail with the right hand and holds her up, head do\vnward. If 

 unripe, the fish is returned to the pens; if ripe, the spa\\-n will be loose and soft and mil run down 

 toward the head, leaving the region of the vent loose and flabby, and the operator, retaining his hold 

 of the tail with his right hand, places the head of the fish under his left arm with the back uppermost, 

 the head highest, and the vent immediately over the pan. At first the fish generally struggles violently 

 and no spawn will flow; but as soon as she yields, the eggs flow in a continuous stream rattling sometimes 



