PROGRESS IN BIOLOGICAL INQUIRIES, 1931 507 



grams to meet the increasing demand for game fish in public waters. 

 Along with this immediately practical program, fundamental studies 

 concerning production of fish food and fish in unit areas of water of 

 different types are being planned. The ecology and distribution of 

 the little-known fishes of the Rocky Mountain region are being 

 investigated as a part of the survey work in these areas. 



WASATCH FOREST INVESTIGATION 



The Wasatch forest has been designated as an experimental area in 

 which fish-cultural experiment and stocking programs can be carried 

 out to the ultimate benefit of the entire Rocky Mountain region. As 

 a basis for this work, a preliminary biological survey of representa- 

 tive lakes and streams was undertaken. Collection of the field data 

 during the seasons of 1930 and 1931 was made by Prof. Vasco M. 

 Tanner, of Brigham Young University, who, with a staff of four 

 assistants, spent the months of July, August, and September in a 

 reconnaissance survey of the representative lakes and streams of 

 this area. During the first season 86 lakes and a few" streams were 

 examined. The summer of 1931 was devoted primarily to a study 

 of the principal stream systems, although some lake study was also 

 carried out. A total of 107 lakes and 34 stream systems were 

 examined during the two seasons. 



Lake studies. — The majority of the lakes of the Wasatch Forest 

 lie at elevations from 9,500 to 11,500 feet. The growing season for 

 most forms of aquatic life, including the trout, probabl}^ does not 

 exceed four months, judging by the fact that the ice does not dis- 

 appear from the majority of the lakes until June and begins to form 

 early in October. 



Although locally termed as lakes, these bodies of water are all 

 relatively small, varying in size from 1 to 160 acres and having a 

 total area of only 1,715 acres. They are for the most part shallow 

 lakes of glacial origin. 



The entire drainage area being in pre-Cambrian quartzite, the 

 water is extremely soft, varying in pH from 4.9 to 5.5, with a bi- 

 carbonate content of from 5.5 to 15.2 parts per million. Dissolved 

 oxygen of the surface water varies from 6.2 to 8.9. 



The lakes studied, classified according to the type of shore, are : 

 Rocky, moorland or boggy, and reservoir lakes. Although inter- 

 mediates between the first two classes are common, the latter type, 

 though a man-made class, is quite distinct in chemistry and biota. 

 The first class is characterized oy rocky shores and bottom; shallow, 

 clear water rich in oxygen and exceedingly low in carbonates and a 

 sparse fauna and flora. The boggy-shore type is found in stream 

 valleys, usualW surrounded by boggy meadows. These lakes have 

 mucky bottoms, and the oxygen tends to be reduced in the deeper 

 waters due to the decomposition of organic matter and to the small 

 size of tributary streams. A fair abundance of a few species of 

 organisms makes up the food supply. The reservoir type is usually 

 the result of damming originally boggy-shore lakes to increase their 

 storage area for irrigation purposes. Great fluctuation in water 

 level occurs in contrast to the fairly constant area of the other types. 

 Food of the bottom and plankton types is quite abundant at low- 

 water stages, probably due to concentration with decrease in area. 



