Manchester Memoirs, Vol. Ivii. (191 3), No. V*. 19 



salmon in that river. With this reservation this paper 

 must be looked upon as a means to an end and not as a 

 final conclusion of any part of this vast subject. 



Summary. 



I. There appears to be some relation between the 

 length of time spent in the river and in the sea, i.e., 

 when a young fish lingers in the river for a considerable 

 time it remains in the sea for a comparatively short 

 period and vice versa. 



II. This seems to indicate that among the salmon 

 in the \V}e, at any rate, there appears to be a more 

 or less definite age for sexual maturity. 



III. The temperature of the water may possibly 

 be one of the determining factors of the length of 

 time spent in the river before migration. 



I\'^. Those salmon which have a short sea-life are 

 longer for their weight and show more variation in 

 their measurements of lengths, girths and weights 

 than those remaining in the sea for some time. 



V. The infrequency of spawning of the salmon. 

 The spawning period appears to be more fatal to 

 " spring " than "summer " salmon. 



VI. There appears to be no definite law governing 

 the migrations of the salmon. The time of year at 

 which a fish enters the river to spawn appears to be 

 of no importance as an indication of racial differences 

 among salmon. 



VII. The results indicate that the salmon is not as 

 a rule an annual spawner, but in the majority of 

 cases, where the salmon does return to spawn for the 

 second time, it is in the year but one following that in 

 which it first spawned. 



