380 Report of Experiments on the Salmonidce of the Tweed. 



No. II.— FISH MAKKED IN 1871 AND 1872. 



Eecaptured. 



25 Salmon, 1 



177 Grilse - • - 2 



153 Bull-Trouts ... 4 



6 Whitling, 3 



454 Blaektails, - - 18 



9 Silver-Whites — 



40 Smolts — 



400 Orange-Fins - - . - 1 



31 Parr, — 



1 Grayling, - - - — 



2 Yellow Trout, ... 2 



Total, 1298 31_ 



If any doubt has existed hitherto, it can no longer exist, that 

 a Blacktail and a Whitling are the same fish in different stages 

 of growth, and likewise it is proved that Blaektails are subse- 

 quently retaken as Bull-Trout ; but the proof is not obtained 

 that the Whitling is an intermediate stage between Blacktail and 

 Bull Trout, one case actually leading to the inference that a 

 Whitling remains a Whitling, a perfect fish ; 1 year and 299 days 

 having elapsed between the two periods of its capture as a Whit- 

 ling. If this should be so, there must be more than one species 

 of Blacktail. The present series of experiments has not deter- 

 mined (what, however, has been perfectly established formerly), 

 that the Orangefin is the previous stage of the Blacktail. It will 

 be expedient, however, to continue the examination of Blaektails 

 and other fish of similar dimensions, with the view of removing 

 the uncertainty existing on these points, as well as of discovering 

 some of the Orangefins and Smolts which have been, or shall be, 

 marked ; and, if possible, to settle the value of certain theories 

 relative to distinctive shapes of the earlier age, supposed by some 

 to indicate the future Salmon, Grilse, or Bull-Trout, as the case 

 may be. 



No certain light has yet been thrown on the question whether 

 Grilse become Salmon. One Grilse, marked in November, 1870, 

 was retaken as a Grilse in the following February ; but it had 

 decreased in weight, and can afford no criterion for decision. 

 Another Grilse, marked February, 1872, was recaptured still in 

 the Grilse state on 28th August, 1872 — six months after being 

 marked. On the other hand, several Salmon have been noticed 

 in the Berwick Shipping Company's fish-house, with scars, cor- 

 responding in position to the place where the wires are inserted 

 in the tail of the Grilse. The Committee propose to adopt another 

 method of marking Grilse, and thus test the power of the hypo- 

 thesis, that the wires having been rubbed out by the power of 



