124 



F. DAY : PERIODS OF MIGRATION. 



river the netting takes place, the greater is the percentage of males 

 to females which are caught. 



Mr. Anderson writes to me respecting the Forth, and the 

 migrations of salmon and grilse therein, remarking that his 

 observations extend over a period of 50 years. (1) The first run 

 of salmon, the beginning of December till nearly the end of 

 February, should there be a fresh in the river; they are coarse- 

 looking fish, from 16 lbs. to 30 lbs. (2) About the middle or 

 second spring tide in February, clean spring-run fish ; the fish 3 lbs. 

 or 4 lbs. in weight, increasing in weight every week until the end of 

 April, when some are from 8 lbs. to 10 lbs. (3) The summer 

 salmon enters with the first spring tide in May, or earlier should the 

 river be in flood ; they are from 12 lbs. to 20 lbs. (4) The first run of 

 grilse, from ij lbs. to 3 lbs., enters the river in May: in 1881, the 

 first were recorded on June 28th, and in 1882, a week later. (5) The 

 second run of grilse ascends about the middle of June, or during 

 the second spring tide ; they are from 3 lbs. to 5 lbs. (6) The 

 'autumn salmon ' ascend at the end of June; are from 16 lbs. to 

 40 lbs. (7) With the first spring tide in July, quantities of grilse 

 ascend. (8) With the first spring tide in August, grilse from 8 lbs. 

 to 16 lbs. ascend in shoals, and many are heavy in spawn. (9) The 

 • grey schule salmon,' or the regular breeders, ascend with the first 

 spring tide in September, or later if the water is low. Many are 

 from 20 lbs. to 50 lbs.; some are very dark, others very red. 

 (10) There is also the 'grey schule grilse'; the most are ugly looking 

 fish, dark red and grey, very coarse made fish ; the males with long 

 snouts, and very shiny all over their scales. 



Russel (The Salmon, 1864) remarked that the reason salmon 

 ascend rivers more or less every month of the year, while grilse only 

 do so at certain periods, or so to speak come all at once, must be 

 owing to one being an adult form capable of ascending at any time,, 

 while the other is a young fish which first attains to that capacity at 

 that season when its ascent is practically bound to begin. The 

 following return shows the proportions of salmon, grilse, and trout 

 to every 1,000 of each kind caught on an average of years in the net 

 fisheries of the river Tweed : — 





Salmon. 



Grilse. 



Trout. 



February (2nd half of) 



22 



0 



8 



March 



- 56 . 



0 



7 



April ... ... 



.. 89 . 



0 



23 



May 



.. 128 .. 



1 



.. 56 



June 



..-.i 3 8 .. 



13 • 



•• i73 



Naturalist, 



