MIGRATION AND HYBERNATION. 141 



it be, the herring, for instance, still holds its 

 own. 



In studying migratory movements many facts 

 have to be kept in sight, and a close watch has 

 to be placed on the migrants in order that we 

 may discover, if possible, whether, there is 

 any return of those fishes which move to some 

 distant spot for the purpose of depositing their 

 eggs, and what, if any, changes are under- 

 gone in the appearance of the pilgrims during 

 their journeys to and fro. Some of the more 

 interesting of the details of this aspect of the life 

 history of fishes will be discussed now. 



The migration of the salmon may fittingly 

 come first under consideration, and illustrates the 

 migration from salt into fresh water, of which 

 we have already hinted. The efforts which the 

 salmon makes to gain the upper waters of the 

 rivers they ascend may often be truly described 

 as Herculean. Kapids, even of six feet high, 

 they surmount by leaping, trying again and again 

 until successful (see frontispiece). In some of 

 the Scotch rivers artificial stairs have been con- 

 structed in order to enable them to overcome 

 some of the otherwise unsurmountable barriers. 

 " Excelsior" seems to be the salmon motto. So 

 violent are their exertions that they have per- 

 force often to rest for days in some quiet pool, 

 from whence they continue their struggle up- 

 wards. At last the Mecca of the pilgrimage is 

 reached ; but the journey and the nature of its 

 termination tells sadly upon both males and 

 females. "To such," writes Mr Eooper, "as 

 have only seen the salmon in prime condition, 



