MATURITY 143 



their first descent as smolts may vary is at least suggested, if it is not 



proved, by examination of the scales. Out of the 45 sets of scales of 



Loch Lomond fish examined by Mr. Hutton and myself, one fish, a late 



descending smolt (Fig. 30) had not reached the sea at all. Of the 44 



others the scales indicate a residence in salt water subsequent to descent 



thus : — 



23 remained in the sea over o winters (Fig. 45). 



16 remained in the sea over i winter (Fig. 46). 



4 remained in the sea over 2 winters (Fig. 47). 



I remained in the sea over 3 winters (Fig. 48). 



The 23 first noted of course ran as whitling in the same year as they 



descended as smolts, and it is interesting to note that of these, as I 



have stated, 5 showed evidence of spawning. 



I am unable, with the data at my command, to deduce any general 



principle as to the effect which continuous residence in the sea without 



spawning may have upon the growth of the sea-trout in contrast to its 



rate of growth when spawning has early occurred and thereafter been 



continued each year. The variations are bewildering even in the few 



data which I possess. For example the fish which remained over 3 



winters in the sea without spawning, whose scale is shown in Fig. 48, 



weighed 1 1 lb. Its record is as follows : — 



Fresh-water life ... ... ... 3 years'! 



Sea life without spawning ... 3 years J-8.^ years= 1 1 lb. 

 Sea life with spawning ... ... 2^ yearsj 



The fish which remained over 2 winters in the sea without spawning, 



whose scale is shown in Fig. 47, weighed 4^ lb. Its record is : — 



Fresh-water life ... ... ... 3 years"J 



Sea life without spawning ... 2 years V5. I years = 4^ lb. 

 Sea life with spawning ... ... ^ year J 



But I give (Fig. 49) the scale of a fish which spent 3 winters in the sea 

 without spawning, and although 1 1 years old weighed only 2^ lb. Its 

 record is : — 



