liv Field Columbian Museum —Zoology, Vol. V. 



tributaries of the Rio Lerma. I was not aware until March 18, 1903, 

 that any effort had ever been made in Mexico to hatch trout, at which 

 time I made a trip from the city of Mexico to Lerma, the head waters 

 of the river of the same name, to collect fishes there. The station 

 agent kindly directed me to a German, Mr. Vincente Richter, living 

 some six miles distant, whom he said had many fishes. On arriving 

 at Mr. Richter's house I was much surprised to see a quite well regu- 

 lated fish hatchery, which has been in existence for about fifteen years, 

 in full operation. , It is on the hacienda owned by Senor Eduardo Gon- 

 zales, to whom the government pays a fixed annual sum for its main- 

 tenance. One-half to one million of eggs of the rainbow trout are 

 hatched here annually. Several large springs form the source of the 

 Rio Lerma at this place, and from these an abundance of water is 

 obtained for the hatchery. The temperature of the water at its 

 source is about 55° F., and its volume is so great that the temperature 

 is not more than one or two degrees higher when it reaches the hatch- 

 ing troughs. Considering the great abundance of water, and the 

 facility for making suitable ponds at only a moderate expense, the 

 abundance of small Crustacea, insect larvae, and the like, which are 

 excellent food for the young trout, Mr. Richter is certain that trout 

 can be raised here for the markets of the City of Mexico with profit. 

 There are native trout in the Pacific streams of Mexico as far south 

 as Durango. The experience of Mr. Richter indicates that trout will 

 flourish as far south as the Rio Lerma. On the Atlantic slope near 

 Jalapa are many mountain streams flowing through dense forests in 

 which I believe trout would flourish. In many of these streams there 

 are few or no fishes. The fact that there are no fishes in some of these 

 streams, is, however, no indication that fishes will not live in them. 

 Fishes are evidently not there because they have not been able to 

 ascend the many falls and cascades, and at the head waters it is quite 

 evident that there has been no center of distribution. 



One of the most promising fields for the introduction of food and 

 game fishes is in the Lerma Basin, for in this region are many streams 

 and lakes in which many species of small fishes abound which would 

 furnish an abundant supply of food for the larger introduced species. 



In introducing fishes into a country the conditions should be 

 carefully studied in order to avoid the selection of unsuitable species. 

 The lakes in the Lerma basin should in my opinion be an ideal place 

 for the large-mouth black bass. The rainbow trout would probably 

 do quite as well and not disturb the present fish fauna as much as 

 would the black bass. 



