CHAP, v.] GRILSE GROWTH. 191 



not to interrupt the fish in their swimming operations nor be 

 troublesome to them in any way. After their journey to sea 

 and back again, we found that the four pound grilses had 

 grown 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 a 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 observations, having tickets made for the pur- 

 pose, 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 



