60 BRITISH FRESHWATER FISHES 



extends only to below the posterior edge of the 

 pupil. 



The Trout smolts, when they finally leave the 

 estuaries, do not go so far out to sea as those of the 

 Salmon, but feed near the coasts, and by the end of 

 the summer are usually not much less than a foot 

 long ; in the winter they feed but little, and in the 

 larger rivers, or where the burns flow out of ac- 

 cessible lochs, many of them may join the autumn 

 runs of larger breeding fish and pass the winter in 

 fresh water, returning to the sea in the next spring 

 and, as a rule, running up to spawn in the following 

 autumn. Thus we see that in the early part of the 

 year there are migrating to the sea smolts, three- 

 year-old fish, and larger fish which have spawned, 

 and in the summer and autumn there run up not 

 only breeding fish, but fish about 2j years old, 

 which have been only a few months in the sea. 



The rate of growth is very variable, but is slower 

 than that of the Salmon ; after one summer in the 

 sea the length is usually about 10 to 12 inches, and 

 the weight I Ib. or less ; during the second summer's 

 sea-feeding the length usually increases to about 

 1 8 to 20 inches, and the weight to 2 or 3 Ibs. ; 

 a female fish of this size is figured (PI. VI, Fig. 2). 

 In the next season this weight may be doubled, so 

 that a fish of 5 or 6 Ibs. captured towards the end 

 of the summer may generally be estimated as 4^ 

 years old. However, some Trout appear to go 

 farther out to sea and to grow more quickly than 

 others, and this is especially the case with the Trout 

 of certain rivers such as the Coquet and the Tweed ; 

 in the latter, Sea-trout more than 4 feet in length 

 and weighing nearly 50 Ibs. have been captured. 



