70 



Appendices to Twenty -fifth Annual Report 



On 10th April 1903 a 5-lb. kelt was marked "J. B.-L., 30," Last 

 November I received a letter from John Mackay in which he informed 

 me that a cow of his had died, and that, being unable to account for the 

 animal's death, he made a post-mortem examination, and found in the 

 interior of the cow this particular salmon mark, which he considers 

 caused the animal's death. The most likely explanation of how the 

 mark came to be inside the cow seems to be that the marked fish had 

 died and been washed up on the bank of the river in time of flood. 

 That the cow, which commonly grazed on the banks of the Grimersta, 

 had eaten the dead fish with the mark. It seems that cows will readily 

 acquire the habit of eating fish, and one gentleman who has fished the 

 Grimersta has stated that he commonly used to give one of the Grimersta 

 cows sea trout which he did not want, and that the cow ate the fish 

 readily. Unfortunately, we do not know how long the mark had been 

 inside the cow. The interval of time between marking and the 

 recovery of the mark is three years and seven months — a longer interval 

 than, under normal circumstances, we have yet observed. The incident 

 is analagous to the finding of an American coin inside a stag shot by a 

 friend of my own in the island of Mull. 



The information of outstanding importance has been obtained through 

 the extensive marking of smolts undertaken in 1905 by the Tay Salmon 

 Fisheries Co. In a paper read before the Royal Society of Edinburgh 

 [Proc, Roy. Soc. Ed n XXVI., Part V., p. 321] last July, I have already 

 shown, first, that no grilse marked as the smolts were marked, i.e.,- by the 

 insertion of a small loop of silver wire in the dorsal fin, was captured 

 in 1905, but that a number of grilse so marked were captured in the 

 summer and autumn of 1906, thus most definitely confirming the view 

 that the smolt, going to the sea in April or May, does not return as a 

 grilse to fresh water towards the end of the same season, but appears 

 as a grilse during the summer and autumn of the succeeding year. This 

 was the accepted view in many districts, but in some localities, including 

 the Tay itself, the belief that two or three months in the sea were 

 sufficient to change a smolt into a grilse obtained. This view was, no 

 doubt, accepted owing to the deductions from the famous Stormontfield 

 experiments. It has elsewhere been stated that *' from other observa- 

 " tions it seems certain that all grilse do not, however, enter fresh water, 

 " but that many fish pass the grilse stage in the sea and return for the 

 " first time to fresh water as small spring salmon, four years of age." 



In the spring of the present year this view is being definitely con- 

 firmed by the capture of small spring fish in the Tay bearing the 

 distinctive silver wire inserted by Mr. M'Nicol, of the Tay Fisheries 

 Co., in 1905. The occurrence of the first of those small spring fish has 

 already been noted in The Field by Mr. P. D. Malloch. 



It is thus seen that the dual habit of migration, specially dealt with 

 in the Twenty-second Annual Report, subsists from the smolt stage 

 onwards. At the same time, the uncertainty as to the presence of small 

 spring salmon and similarly-sized grilse occurring at different seasons is 

 explained, while by the marking of adult fish we have already accounted 

 for the presence of the large class of Tay springers. 



So far, therefore, as the rivers of the east coast of Scotland are con- 

 cerned, the leading features of the salmon's migratory habits have been 

 to some extent elucidated by the continued marking of fish. 



