Trout and Salmon i8i 



quivering, or vibrating his body rapidly. This is an outstand- 

 ing courting act not only throughout the salmonid family, 

 but also in entirely different species such as the jewel de- 

 scribed in an earlier chapter. Since a very similar vibration 

 accompanies the actual deposition of the sex products, the 

 layman would be inclined to think that the male is putting 

 on a "pseudo-spawning" or simulated spawning act in order 

 to induce the female to do likewise in earnest, but no scien- 

 tist could allow himself such a thought without suffering 

 the accusation of unseemly anthropomorphism. 



These activities may go on from one to eight hours, de- 

 pending on the diligence of the female and her nesting 

 standards, but eventually a depression some four to eight 

 inches deep and about her own length has been completed 

 which seems to satisfy her, and she suddenly drops into the 

 center of this pit, with her vent and anal fin well down in 

 the deepest part. The male immediately moves up into posi- 

 tion alongside, with his vent opposite hers, and heeled over 

 so that his abdomen is close to hers. With downwardly arched 

 bodies quivering, with open mouths testifying to the muscu- 

 lar strain of the act, they discharge the eggs and milt at 

 exactly the same instant. (See Plate V.) This is important 

 for two reasons: first, because otherwise the milt might be 

 carried away by the current without reaching the eggs, and 

 second, because, although the eggs remain fertilizable for 

 several minutes, the sperms lose their potency within forty- 

 five seconds after they have entered the water. 



Often one or more of the other attending males rush in 

 and take part in the fertilization, the cloud of milt settling 

 compactly about the bright pink eggs as they stream into the 

 nest. The whole process takes about two seconds. The males 

 then disperse, the dominant one returning to his original 

 post. The female starts covering the eggs by digging slightly 



