GEILSE-GROWTH. 135 



into beautiful salmon, varying from nine to fourteen pounds 

 weight. I repeated this experiment for several years, and on 

 the whole found the results the same, and, as in the former 

 marking, found the majority returning in about eight weeks ; 

 and we have never among our markings found a marked grilse 

 go to sea and return a grilse, for they have invariably returned 

 salmon." 



The late Duke of Athole took considerable interest in the 

 grilse question, and kept a complete record of all the fish that 

 he had caused to be marked ; and in his Journal there is a 

 striking instance of rapidity of growth. A fish marked by his 

 Grace was caught at a place forty miles distant from the sea ; 

 it travelled to the salt water, fed, and returned in the short 

 space of thirty-seven days. The following is his entry regarding 

 this particular fish : — " On referring to my Journal, I find that 

 I caught this fish as a kelt this year, on the 31st of March, with 

 the rod, about two miles above Dunkeld Bridge, at which time 

 it weighed exactly ten pounds ; so that, in the short space of 

 five weeks and two days, it had gained the almost incredible 

 increase of eleven pounds and a quarter ; for, when weighed 

 here on its arrival, it was twenty-one pounds and a quarter." 

 There could be no doubt, Mr, Young thinks, of the accuracy of 

 this statement, for his Grace was most correct in his observar 

 tions, having tickets made for the purpose, and numbered from 

 one upwards, and the number and date appertaining to each fish 

 was carefully registered for reference. 



As the fish grew so rapidly during their visit to the salt 

 water, people began to wonder what they fed on, and where they 

 went. A hypothesis was started of their visiting the North 

 Pole ; but it was certain, from the short duration of their visit 

 to the salt water that they could proceed to no great distance 

 from the mouth of the river which admitted them to the sea. 

 Hundreds of fish were dissected in order to ascertain what they 

 fed Upon ; but only on very rare occasions could any traces of 

 food be found in their stomachs. What, then, do salmon live 

 upon? was asked. It is quite clear that salmon obtain in 

 the sea some kind of food for which they have a peculiar liking, 

 and upon which they rapidly grow fat ; and it is very well 

 known that after they return to the fresh water they begin to 

 lose flesh and fall off in condition. The rapid growth of the 

 fish seems to imply that its digestion must be rapid, and may 

 perhaps account for food never being in its stomach when found ; 



