4 EsDAILE, Results of the Sa/inoii Scale Research. 



river, but 5'5% were proved to be exceptional in this 

 respect. 



From these figures it seems that among the \V\-e 

 salmon there is a fairly definite age at which they reach 

 sexual maturity; that is, between four and five years. The 

 majority of the Wye salmon spend two years in the river, 

 and by far the greater number of these, as has been 

 stated above, return to the river after an absence of less 

 than 3 j'ears. Of the remaining 55% those which 

 stay in the river for a considerable period return sooner 

 to the river, and are generally about the same age at the 

 time of spawning as those fish which remain only a short 

 while in the river and a longer time in the sea. All this, 

 therefore, points to the fact that there is a definite age at 

 which spawning generally takes place and that the length 

 of time spent in the river determines the length of time 

 spent in the sea. 



Bearing upon this point Herr Knut Dahl brought 

 forward some veryjnteresting facts in his recent paper (2), 

 and they are of great use when considering fish from 

 other localities. With regard to the relative length of 

 time spent in the river and sea, Herr Dahl shows that the 

 salmon from Finmark, in the north of Norway, remain in 

 the river for a much longer time than the fish from the 

 more southerly districts of Trondhjem and Christiansand. 

 The results indicate that the majority of the fish from 

 Christiansand remain in the river before migration for 

 3 years, while the greater number of fish from Finmark 

 spend 4 or 5 years in the river. Comparing these 

 results with those from the Wj-e, which is about /"S" 

 further south than Christiansand, we find that two }'ears 

 is the average length of time spent in the river. From 

 time to time scales of fish caught in many different 

 localities have been sent to the Manchester University for 

 examination. Several of these fish were from the llamp- 



