THE STORY OF THE SALMON 301 



instinct. Give fish in confinement as much and as care- 

 fully selected food as they can eat, and the silvery smolts 

 are in no way induced to forego their seaward migration. 

 For the healthy growth and development of the species 

 salmon, as we now know it, the bracing qualities of the 

 sea, with its rich feeding, are absolutely necessary." 1 . . . 

 " We have no evidence that smolts would starve in any 

 of our rivers if they did not descend when they do. No 

 doubt they get a greatly increased and varied amount 

 of food when they do go into the sea, but the time when 

 the migration takes place is the time when the best feeding 

 season is commencing, and it seems to me necessary to 

 take the natural instinct for a temporary marine sojourn 

 into account as well as the need for increase of food/' 

 The descent of the smolts is mostly in Spring, and they are 

 often about six or seven inches long when they put on their 

 " sea- jacket." 



The smolts that are successful in making the journey to 

 the sea for they have to run the gauntlet of many dangers 

 enter upon a course of voracious feeding which lasts for a 

 variable period. They devour young herrings and haddocks, 

 the eggs and larvae of crustaceans, and so on, and grow 

 apace. At the same time, the thinning of the crop con- 

 tinues, for a new set of enemies has to be faced gulls, 

 cormorants, coal-fishes, and the like. 



It is a common belief that salmon-smolts, descending to 

 the sea in April or May, may return as " grilse " in June 

 or July of the same year, and it is likely enough that this 

 is sometimes the case. On the other hand, smolts marked 

 by Malloch in 1905 returned as grilse in 1906. 2 Moreover, 

 if it be the case that the character of the lines on the scales 



1 The Life of the Salmon, by W. L. Calderwood, Inspector of Salmon 

 Fisheries for Scotland (Arnold : London, 1907). 



* P. D. Malloch, Life-History and Habits of the Salmon, Sea-Trout, 

 Trout, and Other Fresh-Water Fish (A. & C. Black, 1910, 263 pp.). 



