32 THE LIFE OF THE SALMON 
This is pretty good evidence that the first re- 
appearance in fresh water of the fish which descended 
to the sea as smolts about twenty-six months old is 
not less than a year later when, as grilse, the fish 
are three to three and a half years old. The 
average weight of the Tay grilse mentioned is 
54 lb., which gives an average increase, taking 
fourteen months as the interval, of 6 oz. a month. 
The increase in length may be taken as fully four- 
fold. This rate of increase is surely more in harmony 
with what we know of the growth of other creatures 
having a duration of life similar to that of the 
salmon than with the sensational increase demanded 
by the view previously held, and stated as a proved 
fact by several writers, that grilse come into our 
rivers after an absence of only a month or two. 
Reference has been made to the food of the Black- 
pool smolt. In a little book, now out of print, on 
the natural history of the salmon, written by a 
salmon curer and tacksman of fishings at Inverness, 
named Alexander Fraser, and published in 1830 at 
the Inverness Courier office, I find this shrewd 
observation : “I have found seven small fish in a 
grilse of 34 lb., and several, particularly herrings, 
in the body of salmon.” The writer then goes on to 
speak of the sea as the feeding place of the fish : 
‘‘Salmon in lakes and rivers can, like other fish, 
subsist for some time on little or no food. In the 
river Ness they have been known to continue for 
about eighteen months, the interval between their 
entry and their departure for the sea, and during 
this time their food must be very limited indeed. 
