20 



THE MIGRATION AND CONSERVATION OF SALMON 



Fig. 7. Distant (400 km or more) migrations of salmon marked in Norway in 1937. (From Dahl 



AND S0MME.) 



nitely directed journey. The marking sta- 

 tions have been selected only for reasons of 

 convenience, and in my opinion the results 

 must be interpreted not as simple move- 

 ments from these stations alone, but as in- 

 dices of what is happening on probably the 

 greater part of the coasts along which the 

 stations are situated. 



From the results the inference may be 

 drawn that while the salmon makes a defi- 

 nite migration towards the coast which it is 

 seeking, it does not necessarily set a very ac- 

 curate course for a definite river and the 

 landfall which it makes may be a long dis- 

 tance from its ultimate destination. In 

 Scotland in 1936 and 1937, 34 salmon made 

 journeys of more than 100 miles between the 

 place of marking and the place of recapture 

 which, in the case of those caught again in 

 coastal nets, was not necessarily close to 

 their final destination had they been allowed 

 to continue their passage. Two of these 

 journeys extended to 400 miles. In 1938 the 

 average length of journey has been in- 

 creased. Fifteen of the 16 fish reported as 

 recaptured prior to the middle of June had 



all covered distances of from 200 to 400 

 miles. 



These Scottish journeys have been greatly 

 exceeded by those of some of the fish with 

 which Professor Dahl has been dealing. As 

 in Scotland, he has found the majority of 

 his recaptures within 100 or 150 miles of the 

 places of marking. But in 1937 alone he 

 had no less than 94 salmon which travelled 

 over 150 miles, and of these 17 covered 600 

 or more miles, one of them journeyed no less 

 than 1,150 miles. In 1935 the salmon which 

 was recaught in the White Sea had covered 

 some 1,600 miles. 



That the Baltic salmon should be known 

 definitely to cover up to 800 miles between 

 their native river and their sea feeding 

 grounds, and that the Atlantic salmon 

 should also be known to cover up to say 1,500 

 miles after it has finished feeding, and has 

 again struck the coast on its way back to 

 fresh water, would seem to dispose effec- 

 tively of any difficulties which we might 

 have in postulating possible feeding grounds 

 for these latter fish as situated up to say 

 1,500 miles from both the coast in general 



