236 GROWTH OF SALMON. 



on the growth of salmon than I have already done 

 in the 'Book of the Salmon,' pp. 197-201, as 

 follows : 4 At the end of a year, the whole of it 

 passed in fresh water, the young fish, on an aver- 

 age, weighs little more than three ounces. At 

 that weight, being a smolt, it descends to the sea ; 

 and if it should remain therein, say for eight or 

 nine weeks, and then return to its natural element, 

 fresh water, it will, in all probability, and no 

 specific circumstances preventing, have increased 

 by the end of that time to the weight of five 

 pounds or more. This rapidity of increase is 

 most wonderful ; and though an adult salmon has 

 been known to double its weight by sea-food in 

 thirty-eight days, nothing like the increase that 

 takes place between the smolt and grilse states 

 ever after occurs. So, if the growth of salmon 

 during the first year of their existence is extremely 

 slow in fresh water, it is, after that age, by far 

 more than proportionably rapid in salt water. It 

 will be well to bear in mind that the growth of 

 salmon is not always proportioned to the length of 

 time they sojourn at sea. Several circumstances 

 affect their rate of physical development. Amongst 

 others, indeed, these are the chief ones quality 

 and quantity of food found on the salt-water feed- 

 ing-grounds, and hereditary capacity for growth. 

 By "hereditary capacity " I mean, that the off- 

 spring of large fish have the inherent power of 



