140 THE HABITS OF THE SALMON. 



proximate estimate of the age of salmon of 40 lbs. 

 weight in general, is almost impossible. The age, 

 however, of individual fish of lighter weights can 

 be, and has been ascertained, notably in the case 

 of the marked smolt which was caught the next 

 year, weighing 20 lbs. ; but the fact alluded to 

 about the disparity in the rate of growth of 

 the grilse mentioned by Mr. Cholmondeley Pennell, 

 will show that it would be impossible to form a 

 correct general estimate of the age even of grilse 

 of any given weight. We have ample proof of the 

 astonishing rate at which immature salmon grow, 

 but who can tell whether they continue to grow 

 so rapidly after they have reached the adult 

 stage. Human beings, beasts, and birds continue 

 to grow up to a certain age, and no longer. Is 

 it then unreasonable to assume that in like manner 

 salmon grow very little, or not at all, after they 

 have reached a certain stage of their existence? 

 Again, as regards disparity in their growth. Is it 

 not probable that those fish which have access to 



