of the Fishery Board for Scotland. 



95 



No. 7298 is again a Loch Brora fish. In April 1901 it was marked 

 as a 25-inch grilse kelt of 4 lbs. On 18th March, 1903, it was 

 recaptured as a salmon kelt in Loch Brora. The length measurement 

 showed an increase of 5 J inches, and the weight an increase of only 2| 

 lbs. As a possible explanation of this slight increase of weight it may 

 be mentioned that many of the salmon taken in the North of Scotland 

 during the season of 1902 were remarkably poor in flavour. It is 

 possible that the feeding was not as rich as usual and that hence some 

 fish did not greatly increase their weight. It would follow however 

 from this that these fish ascended rivers when in a poorly nourished 

 state. At no time, however, do the striking increments of weight 

 observed in fish from our largest rivers appear in fish from the Brora. 

 Other circumstances, which may be touched upon later, appear to me 

 to indicate that a small proportion of fish do return to fresh water 

 without being nourished as the average salmon is, and that their return 

 takes place some little time, it may be, before the spawning season. It 

 is quite possible, however, that 7298 may have also been an annual 

 spawner, and that 1902-03 was its third spawning period. A similar 

 case is 7225, marked in March, 1902, and recaptured in March, 1904, 

 both in Loch Brora. The increase of weight is again strikingly small, 

 being only 2| lbs. The conditions of these Brora fish require further 

 investigation. 



Kelt to Unspawned Condition. 



Two fish still require mention under this heading — 1st, No. 6541, a 

 19 lb. kelt 38 inches long, marked on 4th March 1902 at Muiresk on 

 the Deveron — it was reported to be a very well mended kelt. This fish, 

 on 22nd October of the same year, was recaptured in an unspawned 

 condition, at Ardniddle, just above Muiresk. It was then 34 lbs. in 

 weight and 41 k inches long, thus showing an increase of 15 lbs. weight 

 and 3^ inches in length in an interval of 7 months and 18 days. This 

 case is of interest as showing that annual spawning occurs even amongst 

 heavy fish, and, further, it is worthy of note that the fish was a female. 

 The Deveron usually holds a fair number of heavy fish, but even in the 

 Tay, females of more than 30 lbs. are not very common. 



2nd, No. 9622, another Deveron fish marked at DufF House on 10th 

 April 1902, a kelt of 10 lbs., 34 inches long; recaptured at Huntly on 

 the Deveron on 26th September of the same year as a clean unspawned 

 fish of .1.9 lbs., 35 inches long. The interval in this case is 5 months and 

 16 days, the increase in weight 9 lbs., in length 1 inch. 



Reference to Diagram (at p. 98). 



By reason of the recaptures of clean fish which were previously 

 marked as kelts, and which are recorded for the first time in this Report 

 it is possible to estimate what may represent approximately the life of 

 some proportion of the salmon in the Tay. There is, I have not the 

 slightest doubt, considerable variation in the habits of fish even of one 

 river ; two kelts entering the sea at the same time many return at very 

 different times, and this taking place at any period in the lives of such 

 fish will most materally alter the whole of the subsequent history of each. 

 We have already seen that one grils'e kelt may return to the river a 

 clean salmon in a few months, while another may remain in the sea all 

 summer and winter and return to the river a clean spring fish twice the 

 weight of the first. This so-called " Double Migration " or Duality of 

 Migration seems to exist throughout the life of the salmon, but up to 



