140 U.S. BUREAU OF FISHERIES 



and extent of shoal areas, sufficient soundings to indicate the type, 

 inlet and outlet streams, color and transparency, temperature at the 

 surface and at intervals to the bottom, hydrogen-ion concentration, 

 quantity of oxygen and carbon dioxide, alkalinity as indicated by 

 carbonates and bicarbonates, type and abundance of vegetation, rela- 

 tive abundance of fish food, relative abundance and size of game and 

 forage fish, presence of spawning grounds and evidence of natural 

 reproduction and, finally, the quality and intensity of the fishing. 



In addition to this routine examination employed in single studies 

 of lakes and streams, seasonal studies were made at monthly intervals 

 on five typical lakes east of the Continental Divide. At selected 

 stations on these lakes the following data were secured: Transpar- 

 ency, temperature at regular intervals from surface to bottom, chem- 

 ical analyses, vertical plankton hauls, samples of the bottom fauna 

 and of the fish for food and growth studies. The level and temper- 

 ature of several principal streams were also recorded throughout the 

 season. 



Collections of aquatic plants and principal fish foods were secured 

 from all waters studied and whenever possible fish were collected for 

 the purpose of food and growth determination. Certain waters 

 offering special problems were studied more in detail with the object 

 of determining the reason for marked success or failure in planting. 

 The results of natural spawning were deemed a problem of first 

 importance and every effort was made to secure as much information 

 as possible on this subject. 



At the close of field work operations were transferred to the Bu- 

 reau's laboratories at the University of Utah in Salt Lake City, 

 where a study of the data collected is in progress. The results of 

 this survey will appear in a publication by the Bureau when funds 

 for this purpose are available. 



Wasatch National Forest investigation. — Owing to lack of funds fur- 

 ther limnological studies in the Wasatch National Forest, Utah, could 

 not be pursued. The data collected here during the seasons of 1930 

 and 1931 have been studied, and a stocking plan inaugurated for the 

 principal waters of this forest. This plan was followed insofar as 

 cooperation of the Bureau, the United States Forest Service, and 

 the Utah Fish and Game Department could be effected. Although 

 results of this plan will not be apparent for several years, one out- 

 standing success of the survey's recommendations should be men- 

 tioned. One of the principal, heavily fished lakes of the Wasatch 

 was found to be overstocked with poor-conditioned fish at the time 

 of the survey. It was recommended that no more trout be planted 

 here until August 1932, when a limited number of legal fish should 

 be released to replace those removed earlier in the season. This 

 plan was followed and resulted in a marked improvement in the con- 

 dition of the trout and good fishing prevailed throughout the sum- 

 mer. It is beheved that this result indicates the success which can 

 be attained by properly balancing stocking against carrying capacity. 



OTHER LIMNOLOGICAL STUDIES 



Spring Creek investigation. — At the request of the Weber County 

 Sportsmen's Association, an examination of Spring Creek, Utah, was 

 made to determine if food had recovered sufficiently to warrant 



