68 The Salmon 
their silvery coat, continue to add rings to their scales just as those 
in the sea do. 
] have never found a grilse in the Tay with a less number of rings 
than fifty-one, showing clearly that smolts do not return the same 
year as they go down. All the grilse that come up from June to 
December spawn, and those that are long in fresh water have both 
edges of the scales broken off, and by the time they go down as kelts 
are very much _ impaired. 
I have known as many as 
six or eight rings become 
detached, the upper edge 
remaining as it was when 
the fish came from the sea. 
When the kelt grilse enters 
the sea and begins to feed, 
ite sate Once Mors ac) nine 
round the broken part as 
well as round the whole 
Wwe part, and these rings in- 
: ages Me crease in number according 
6 ae to the time the fish remains 
pu the iseaqe hon tnd athe 
time they sushi has spent 
Ls 

BG, Aes es, Aevn Mike aoe in the sea, then, we have 
merely to count the number 
of complete rings from the broken part outwards (Fig. 64). 
For example, a grilse of 7 lbs. weight was caught in August 1906, 
and its scales contained fifty-four rings. It spawned, and went down 
a kelt of 4 lbs. on 1st April 1907, and was caught again on 17th 
August 1907, weighing g lbs. The number of rings it had added from 
1st April to 17th August was seven, making the total number of rings 
sixty-one. Its age, therefore, is four years and tive months. Had it 
remained in the sea a whole year, it would have added sixteen rings, 
and would have weighed about 15 Ibs. In calculating the age from 
