(52 



Appendices to Twenty '-fifth Annual Report 



" transition from fresh to salt water than in some of the other 

 " classes of fish. The later arrivals have the second annual ring in 

 " course of formation, as shown by a narrowing of the interval 

 " between the marginal lines, but the earlier fish have scales not 

 " much different from those of grilse, and it is often difficult 

 " to distinguish between them. The scale of the small fish does 

 " not generally lie so flat as that of the grilse, and may exhibit 

 14 slight curves radiating from the centre to two or three points on 

 " the anterior margin. The lines are puzzling, and suggest that 

 " feeding has been interrupted during the second summer and 

 " resumed in winter. 



" The majority of these fish seem never to have spawned, but 

 " a few specimens may perhaps have been on the redds as small 

 "grilse a year before." 



I have already alluded to the smolts marked with a wire in 1905 

 which returned as grilse in 1906, and in February and March 1907 we 

 have some of the same marking coming back as small spring fish. As 

 these were all " wired " between 25th April and 6th June 1905 we have 

 the time of their migration determined as approximately the same as 

 that of the smolts of the " wired " grilse. If the former were any later 

 it could only be by a few weeks, and we have to seek some other reason 

 for the difference in habit. At the time of writing I have not been able 

 to examine a sufficient number of their scales to say if there is any 

 essential difference between them and grilse in the lines formed up to 

 the time of migration ; but there is a slight suggestion in the particu- 

 lars given below that there may be such a difference, and in that case 

 we shall have to look for the cause in the river and not in the sea. It 

 is quite possible, however, that the variation referred to is purely 

 accidental, as the specimens examined are so few in number. 



Some " Wired " Smolts Recaptured as Small Spring Salmon. 







Number of Lines on Scale. 





Date. 



Lbs. 



Up to Smolt Stage 

 (River). 



After Smolt Stage 

 (Sea). 



Remarks. 







Total. 



1st 

 Year. 



2nd 

 Year. 



3rd 

 Year. 



Total. 



1st 

 Year. 



2nd 

 Year. 





1907. 

 Feb. 18 



„ 21 



Mar. 15 



H 



9 



104 



22 

 21 

 20 



12 

 13 

 10 



10 



9 

 10 



? 

 ? 

 ? 



55 

 12 

 59 



28 

 29 

 30 



27 

 23 

 29 



s r * s s 



rr} £ ur a h 

 Exterior ridges ~ ~ J- a 

 very broad. | gSftjJjj 



An apparent break in the lines of the second summer is nearly 

 always visible on the scales, and looks like a voluntary or compulsory 

 diminution of feeding for some time. Another point seems evident 

 from the marking, and that is that these small springers are returning 

 for the first time, and have consequently never spawned. This corre- 

 sponds with what the scales show, but it must be remembered that 

 salmon similar in size and appearance that have spawned during the 

 previous winter as small grilse are also caught at this season, and it is 

 only by the spawning mark on the scales and sometimes maggots in the 

 gills that the difference can be detected, though it sometimes becomes 

 apparent when the fish comes to table. 



