60 



Appendices to Twenty-fifth Annual Report 



II. Maiden Fish. 

 (1) Grilse. (Plate II.) 



In the Twenty-third Report I pointed out that the scales of all the 

 grilse I had examined showed that they had passed a year or more in the 

 sea after migrating as smolts, and that none of them had returned to the 

 river at an earlier period. For many years this has been a much-disputed 

 point, as some writers held similar views and others believed that the 

 smolt came back within a few months as a grilse, and relied upon the 

 well-known experiments at Stormontfield half a century ago in support 

 of their contention. They also argued that if there was a difference of 

 8 lbs. or 10 lbs. between the May grilse and the August grilse the 

 growth must be extremely rapid, and that, therefore, there was nothing 

 extraordinary in a smolt increasing to a 2 -lb. grilse in the course of 

 two or three months. We have now, however, the indisputable fact 

 that none of the smolts marked in 1905 were recaptured in the same 

 year, and that many of them were retaken as grilse in the following year. 

 For this important advance in our knowledge we are indebted to the 

 Tay Salmon Fisheries Co., under Mr. P. D. Malloch's management, and 

 to the careful way in which Mr. W. M c Nicol marked the delicate fish 

 with a silver wire twisted into a loop which enclosed the front rays of 

 the dorsal fin and yet left room enough for their development. The 

 marking was done between 25th April and 6th June 1905, and the 

 first "wired" grilse was caught on 1st June 1906, when it weighed 

 2|| lbs. The silver loop enveloped the anterior rays of the fin, and 

 their growth had altered its position from the base to 2 cm. higher up 

 the longest ray, which measured 5*1 cm. The greatest care was taken 

 to test the authenticity of all the facts connected with this fish, and 

 there did not seem any room for error, but ample confirmation came in 

 during the season in the shape of other " wired " grilse with a similar 

 history, and so the success of this smolt-marking experiment has been 

 completely proved, not only up to the grilse stage, but to the return of 

 the fish as small spring salmon, and while this is in the press, one has 

 been reported as a young summer fish of 13 lbs., with a few lines of its 

 third years' feeding in the sea visible on the margin of the scale. 

 There has not yet been time for the recapture of any of these "wired " 

 smolts as older fish. 



I have examined the scales of some of these grilse, and now give 

 details. 



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