THE SALMON 187 



period. It is generally supposed that they return to the fresh 

 water about a year after they have left it, and this is probably 

 The Grilse ^^'^^ ^^ ^^e majority. They are now adult, but virgin, 

 stage, salmon, retaining some traces of adolescence and 

 showing a considerable variation in size. Having left the river 

 weighing but two or three ounces each, grilse begin to reappear 

 in fresh water during May, presumably of the next year, weighing 

 from 2 lb. to 5 lb. As the summer and autumn months pass, 

 grilse continue to run, increasing in size as the season advances, 

 being taken as heavy as 10 lb. and even 12 lb. It is possible 

 that these heavy grilse may have remained two whole seasons in 

 the sea before revisiting the river where they were hatched. 

 Their approach to maturity and the rate of development of the 

 ovaries in females* probably depends upon the amount of food 

 which they find in the sea. This was formerly considered 

 to consist entirely of crustaceans — shrimps, prawns, and the 

 like — and to such diet was attributed the beautiful and peculiar 

 hue, the " salmon colour" of the flesh of this fish ; but recent 

 observations have shown conclusively that salmon subsist 

 chiefly upon herrings, haddocks, and other pelagic fish. In the 

 spring of 1899 Dr. Kingston Barton, on opening a salmon taken 

 at sea, found in the stomach no fewer than six large herrings, 

 " that nearest the salmon's mouth being barely changed in 

 appearance, while the sixth had only the spinal column 

 undigested, those in between being in a graduated state of 

 digestion, and yet all these fish were in the one cavity."t In 

 other words, this salmon had swallowed consecutively more 

 than any ordinary human being could attempt at a single meal ! 

 The intestines, also, were very full of fascal matter, showing 

 that this was no exceptional indulgence. Dr. Barton adds a 

 note of the surprising fact that both in salmon and sea-trout 

 the food-fish is always swallowed tail first. 



* Milt capable of fertilising ova is often developed in male parr before 

 they go to sea. 



t [ournal of Anatomy and Fhyswlog}', April, 1900, p, 297. 



