THE SALMON AND WATER TEMPERATURE 137 
the rise in temperature of the lower line, which 
represents the Orchy or upper water. 
Now, from a constant record of temperatures taken 
in the Tay at Grandtully by Mr. Johnston between 
1895 and 1903, coupled with statements as to the 
results of spring angling, it has been possible to pro- 
duce a table showing the maximum and minimum 
readings for each of the early months of the years 
referred to, and to compare the seasons in respect 
of the ascent of spring fish.* The year 1896 was a 
good spring fishing year, when “fish were early and 
ran quickly.” Only once, in January, did the 
temperature reach as low as 36°, the lowest readings 
in February, March, and April being respectively 
39°, 40°,and 43°. The highest readings for the four 
months were respectively 41°, 44°, 43°, and 51°. 
The average of the maximum readings is 44°7°, and 
of the minimum readings 39°5°. Poor fishing years 
when compared to this show at least 3° lower tem- 
perature in both maximum and minimum averages. 
In other words, with the river temperature com- 
monly above 40° in the first four months of the year 
salmon are running up freely and quickly, and the 
stock of spring fish is largely dependent upon favour- 
able conditions for ascent in January before the 
opening of the netting season. This is exactly the 
condition we find in the Ness and Awe, and we are 
not surprised to find that the early fish of those 
rivers run quickly through the few miles of water 
(each river is only about six miles long) into the 
large lochs, where the temperature of the water is 
* Loe. cit. p. 78. 
