THE TROUT OF THE SIERRA SAN PEDRO 

 MARTIR, LOWER CALIFORNIA 



BY 



JOHN OTTERBEIN SNYDER 



Members of a recent expedition from the Museum of Vertebrate 

 Zoology to the peninsula of Lower California obtained and carefully 

 preserved a considerable number of examples of a rare species of trout, 

 Salnio nelsoni Evermann. For reasons that will appear, it has seemed 

 worth while to extend somewhat the original description of the species 

 before the series was broken up through distribution to other museums. 

 At the request of the Director of the Museum of Vertebrate Zoology 

 this study was undertaken and the present report of results offered 

 for publication. 



Mr. Chester C. Lamb, Assistant Curator of Mammals, Museum of 

 Vertebrate Zoology, Avho participated in securing the collection, has 

 this to say regarding Sal mo nehoni: 



So far as known, only one stream in Lower California is inhabited by trout, 

 namely, the Santo Domingo River. This stream heads on the west slope of the 

 San Pedro Martir Mountains, and the trout exist chiefly in one of its branches, 

 San Antonio Creek, and in that branch almost altogether above Rancho San 

 Antonio. At the time our fish were collected, it is believed that the species 

 existed in only about five miles of the course of the stream, for the reason that 

 at least 15 miles of the lower course was, at that season, dry. About five miles 

 above Rancho San Antonio are waterfalls above which no trout are known 

 to occur. 



There are persistent rumors to the effect that sooner or later the waters of 

 this stream are to be diverted for power purposes from a point above those 

 falls, in which case, unless the trout be transplanted to other waters, the species 

 would become extinct. It is believed that there is no other stream in the region 

 that affords permanent flowing water, such as the trout could survive in. 



• The caiion of the river in which these trout live is narrow and 

 deep, and the water, according to Mr. Lamb, at times becomes warm. 

 Insect life, too, is plentiful. The trout were found to be exceedingly 

 abundant and easily caught. About 150 were taken on two fly hooks, 

 one a brown hackle and the other a roj^al coachman. 



From an examination of the collection, 60 specimens in all, it seems 

 evident that Salmo nelsoni is but a geographically isolated form of 

 the rainbow trout which is common to many of the streams in the 



