346 MR YOUNG ON THE GROWTH OF GRILSE AND SALMON. 



rivers depended mainly on wind and weather being suitable to their upward 

 entrance at the time of their nearing the mouths of the fresher waters. 



To settle this point I commenced, in 1836, to catch and mark all the spawned 

 fish I could obtain in the course of the winter months during their sojourn in the 

 rivers. We frequently fished all the pools of a river with net and coble ; and, 

 as soon as we drew the fish ashore, we made a peculiar perforation in their tails 

 with the nipping-irons, and threw them back into the water. In the course of 

 the following fishing season we caught great numbers of them after their return 

 from the sea, each in its own river with its distinctive mark. 



We have also another proof of the fact, that the different breeds or races of 

 salmon continue to revisit their native streams. You are aware that the river 

 Shin falls into the Oykel at Invershin, and that the conjoined waters of these 

 rivers, with the Carron and other streams, form the estuary of the Oykel, which 

 flows into the more open sea beyond or eastwards of the bar, below the Gizzen 

 Brigs. Now, were the salmon which enter the mouth of the estuary at the bar 

 thrown in merely by accident or chance, we should expect to find the salmon of 

 all the various rivers which form the estuary of the same average weight, for, if 

 it were a mere matter of chance, then a mixture of small and great would occur 

 indifferently in each of the interior streams. But the reverse of this is the case. 

 The salmon in the Shin will average from 17 lb. to 18 Ib. in weight, while those of 

 the Oykel scarcely attain an average of half that weight. I am therefore quite 

 satisfied, as well by having marked spawned fish descending to the sea, and 

 caught them ascending the same river, and bearing that river's mark, as by a 

 long continued general observation of the weight, size, and even something of the 

 form, that every river has its own breed, and that that breed continues, till cap- 

 tured and killed, to return from year to year into its native stream. 



I may now mention that I commenced marking grilses, with a view to ascer- 

 tain that they became salmon, so far back as 1837, and have continued to do so 

 ever since, though never two years with the same mark. The result in respect to 

 growth in each of these earlier years corresponded exactly with what I have given 

 in more detail regarding the years 1841 and 1842. 



The following lists are extracted from the note-book in which I have care- 

 fully recorded the peculiar marks, the periods of marking, the weight at each 

 period, the time of the recapture, and the increased weight. 



List of Smolts marked in the River, and recaptured as Grilse, on their first ascent from the Sea. 



Period of Harking. Period of Recapture. Weight when Retaken. 



1842, April and May. 1842, June 28. 4 lb. 



... ... July 15. 6 lb. 



15. 5 lb. 



25. 7 lb. 



25. 6 lb. 



... 30. S^lb. 



