169 



Report of the Experimental Committee of the Tweed Com- 

 missioners, presented to the General Meeting on jfth 

 September, 1876. 



The Committee, which was reappointed in September, 1875, 

 met at the Union Bridge, on 10th November, when 185 Black 

 Tails were marked with numbered silver wires and returned 

 without injury to the river. It will be seen by the schedule ap- 

 pended hereto that one of these fish, marked on that day at 

 Heughshield, weighing 13 oz., and measuring 13 inches in 

 length, was recaptured on 4th July, 1876, 237 days afterwards, 

 at Longrack, Stirling, weighing 28 oz., measuring 17 inches, and 

 in the character of a Bull Trout. This is the second instance in 

 which a fish marked as a Black Tail in the Tweed has been cap- 

 tured in the Forth ; in the former instance, a Black Tail marked 

 at Start, on October 12, 1871, was caught as a Bull Trout on 

 August 13, 1872 (ten months and one day afterwards), at Fallin, 

 near Stirling. A Black Tail, likewise marked at Start, on Sep- 

 tember 19, 1872, was recaptured on 18th July, 1873, after 302 

 days' interval, in the river Dee (Aberdeen) as a Bull Trout. 

 This fish had increased from 18 oz. in weight, and 15 inches in 

 length, to 36 oz. and 18 inches respectively. A Black Tail, 

 marked on 29th Sej)tember, 1870, at Scotch New Water, weigh- 

 ing 16 oz., and measuring 13 inches, was also recaptured as a 

 Bull Trout, weighing 2 lbs. 1 oz., and measuring 18 inches, at 

 North Esk, Montrose, on 25th September, 1871, 11 months and 

 27 days after being marked as a Black Tail. 



Numerous instances have been reported by the Committee of 

 Black Tails as having been marked and recaptured in the Tweed 

 as Whitling or Bull Trouts, at intervals varying from 12 to 1350 

 days ; and the experiment at Carham pond, alluded to hereafter, 

 points distinctly to the conclusion that most of the Orange Fins 

 placed there on 7th May, 1874, have passed through the inter- 

 mediate stage of Black Tail to that of Whitling or Bull Trout. 



In March last a small pond was excavated at Carham, and the 

 water from Carham Burn, flowing into it through a pipe, was 

 made to pass over rock salt, chloride of magnesium, sulphate of 

 magnesium, chloride of potassium, and bromide of magnesium, 

 so as to represent, as nearly as might be, sea water. 



A dozen of the fish were on 9th March placed in this pond ; 



