206 HOW OLD SALMON MAY BE. 



main in salt water several months.* Doing 

 so is exceptional, because as smolts frequently 

 emigrate in shoals, so grilse or salmon very often 

 immigrate in company. Hence there is " a sal- 

 mon season " and a " grilse season." If fish 

 from the same river and of the same age, con- 

 tinue all along travelling companions, slight will 

 be the difference in their appearance, on their 

 revisiting their haunts of infancy. 



It is impossible to state with anything like 

 accuracy, the number of years salmon may live ; 

 nor can I devise any sure means of ascertaining 

 such information. Migration to the sea being 

 necessary to the physical development of salmon, 

 it must likewise be necessary for the prolongation 

 of its existence. Salmon, like pike and nearly all 

 the carp tribe, cannot be confined in ponds or 

 stews to discover whether they are long-lived or 

 not. Salmon must have runnins; water over a 

 gravelly bottom to breed in, and sea-water and 

 the various kinds of food it produces, to thrive and 

 grow. If confined to ponds, or even to lakes, 

 salmon would cease to increase and multiply ; 

 and their growth would be so much retarded and 



* The earliest return recorded by ]\Ii\ Young ia five 

 weeks and three days, and the latest fourteen weeks. 



