The Salmon I 
netting during the autumn and winter. About fourteen months after 
the smolts have migrated, a run of small grilse appears. The first 
usually arrive during the last week of May or the first week in June, 
and in the Tay weigh from 14 to 24 lbs., while in some rivers they are 
even smaller. Most of the northern rivers are much earlier than the 
Tay, and grilse make their appearance as early as the first week in 
April. As the season advances the weight of the grilse increases 
rapidly. This is due to its food being most plentiful in the summer 
months. At the end of June they weigh about 5 lbs., at the end of 
July 8 lbs., and at the end of August ro lbs.—exceptionally large ones 
weighing from 10 to 12 lbs. In cold, backward seasons they are much 
smaller, and this applies to all rivers in Great Britain. The grilse 
distribute themselves over the whole river, and the run continues until 
the end of December. In the first week of November spawning 
commences. Many return to the sea soon after spawning, while 
others remain until April, and are very greatly reduced in weight, 
averaging from 2 to 7 Ibs. Their sojourn in the sea varies from three 
and a half to eighteen months. During this interval a rapid increase 
in size takes place, and they return again as salmon, double their 
former weight. They first return about the middle of June (see 
scales of a grilse after its second return from the sea), and increase in 
number and weight until the end of December, their age at the latter 
date being four years and nine months. Others remain in the sea 
during the winter, and do not return until the next summer, having 
been away for one and a half years. Thus some spawn in each of two 
consecutive years, while others only spawn once in that time. Unless 
one has studied scales, it is difficult to distinguish between a kelt grilse 
of 4 Ibs. and a kelt of a small spring fish of the same weight. This 
can easily be done, however, by counting the number of rings on the 
scales, or the number of contractions on the scales. 
Hitherto it was thought that the small and the large spring 
salmon were from kelts of grilse of the previous year, but this is not 
the case. The small spring fish are of the same age as these grilse. 
They come up in the following spring, and are from 15 to 4o lbs. in 
