142 SALMONOID HYBRIDS 



produces a hybrid. Owing to the facihty of 

 cross-fertilization (accidental) between these 

 species (trout, white-trout and salmon), the 

 production of salmonoid hybrids is of frequent 

 occurrence and the cause of much confusion to 

 anglers and others, who are often puzzled to 

 identify these fish. A consequence of this is 

 that many local names have come into use 

 which are extremely misleading, especially to 

 the uninitiated who might naturally suppose 

 there exist a variety of thalassadromous sal- 

 mon, whereas, probably, there are only two 

 fixed species, all variants being hybrids of one 

 and another of these three species (including 

 trout). 



Salmon, whose ancestors, we believe, were 

 trout, having thus outgrown the river to such 

 an extent that it was no longer possible to 

 obtain food in it, systematically journeyed to 

 the sea to cater for themselves, returning to 

 fresh water for breeding purposes only. This 

 they continue to do, because, being river fish, 

 fresh water is essential to the hatching and 

 maintenance of the young for the first year, 

 when their appearance is so similar to that of 

 trout of the same age as sometimes to puzzle 

 the angler himself to distinguish them apart. 

 When, after sojourn in the sea, the fish returns 

 to the river, the digestive organs lapse into a 



