Fishes. 4833 



In May and June, 1855, a large proportion of the fry, having then 

 reached the condition of smolts and manifesting the most undoubted 

 evidences of the time of migration, having arrived, the sluice of the 

 pond was removed, and free egress given to all the fish which might 

 desire their liberty. During the latter part of May, and the earlier - 

 days of June, almost all the silvery-coated smolts had voluntarily left 

 the pond, and drifting daily, in shoals of from 1000 to 10,000, into a 

 temporary erection at the confluence of the conduit and the river, con- 

 structed for the convenience of marking, were, after suitable numbers 

 had from time to time been marked, allowed ultimately to escape. 

 About one in one hundred, we believe, was the proportion so marked. 

 On May 29 a very much larger number than on any other day sought 

 for the river, and a proportionally large quantity were of course 

 marked. 



And now, on Friday last, the 20th of July, after an absence of not 

 more than two months, we have the perfectly indisputable result of 

 one at least of those smolts, so shortly liberated, having returned from 

 the sea a beautiful and well- grown grilse of 5j rbs. weight. 



The very largest of the smolts which left the ponds in May and 

 June measured only about 7 inches in length, and weighed from J to 

 1 oz. The grilse caught on Friday measures 24f inches in length, and 

 12j inches in circumference, weighing, as we have said, 5 J lbs. That 

 the comparative sizes of the same fish at the two stages of its growth 

 may be more easily and accurately apprehended, a very beautifully 

 executed photograph has been taken by Mr. Cumming, — now prac- 

 tising that wonderful art in this place, — for the purpose of being 

 printed, of the marked grilse caught on Friday, along with a preserved 

 specimen of the largest size of the smolts as they were liberated in 

 May and June. 



Thus is one more perfectly irrefragable proof afforded of the fact, 

 which for some time, indeed, has been satisfactorily enough esta- 

 blished, that the young of the salmon which migrate to the sea in the 

 earlier part of the season as smolts, return in the later part of the same 

 season as grilses. This is the first occasion, we suppose, of the fact 

 having been publicly demonstrated in the Tay : but in other rivers it 

 had been clearly proved years ago. In a very interesting and valuable 

 work on the ' Natural History and Habits of the Salmon,' by 

 Mr. Andrew Young, of Invershin, superintendent of the Duke of 

 Sutherland's extensive fishings, we find the following stated as the 

 result of that gentleman's repeated experiments in regard to this 

 point : — 



