62 



FISH AND GAME COMMISSION 



Figure 23. Anglers on Rush Creek test stream, Mono County, May 2, 1948 



10,000 LV trout planted, 8,881 (88.8 percent) were caught in 172 days of fishing; 

 7,020 of these were talten by July 31st. Unmarked fish contributed 13 percent 

 of total catch for 1947 ; and 1,104 were browns, 214 rainbow, and 33 were eastern 

 brook. Average catch per angler hour for the season was 0.52. Per mile use of the 

 stream in 1947 is discussed. 



Report of Aquatic Plant Control at Twin Lakes, Mammoth, Mono Co., 

 California. Submitted December 8, 1947. 13 pp., 1 tbl., 6 figures (5 photos) . 



Ahstract: The two lower Twin Lakes over a period of years had become 

 obstructed by dense aquatic plant growth, chiefly A7iacharis. The main portion 

 of the center lake (12.7 acres) and the lower lake (9.4 acres) were each treated 

 with 700 pounds of sodium arsenlte, with 75 percent arsenious oxide, mixed with 

 water and applied as spray. Effective initial concentration for the center lake 

 was 2.6 p.p.m. and 4.0 p.p.m. for the lower lake. Collapse of plant growth reopened 

 the entire 12.7 acres treated in the center lake nearly a month after treatment; 

 and by onset of winter freezeover two and one-half weeks after treatment in 

 the lower lake, 7.7 of the entire 9.4 acres had been reopened by similar collapse. 

 Fish loss was negligible. Since sodium arsenite will not control or eliminate 

 aquatic vegetation permanently, periodic treatment of the Twin Lakes, important 

 for angling and recreation, may be necessary. 



VESTAL, Elden H. and LEWIS, Robert C. 



Report on Airplane Fish-planting Tests in Mono County, California. 

 Submitted August 12, 1946. 8 pp. 



Abstract: Using division plane, tests were conducted with CT 50-ounce, 

 RT 10-ounce, 3-ounce, 6- to 8-pound, and with four brood fish from Hot Creek 

 Hatchery. Fish were dumped directly, dropped in containers with and without 

 lid, and in containers slung from a canopy cargo chute. Heights of release varied 

 from 25 feet to 1,000 feet, with most drops from 300 to about 450 feet. The aver- 

 age speed of the plane was about 100 miles per hour. Drops were made in the 

 morning from 7 to 11 a.m. Free-fall planting from 300 to 400 feet seemed to be 

 the most successful in the direct release series. Fish from 50 to three ounces sur- 

 vived direct release better than larger fish used. EB responded better than RT. 

 Pish not Immediately stunned swam for cover or deep water ; majority of fish 

 stunned recovered in two to five minutes. Predation (gulls) was high in first five 

 minutes after release. Fish planted by direct release of containers were mostly 

 killed or injured. Chute method was most successful of all tried — fish arriving 

 at impact area in excellent condition. Repetition of tests is recommended with 

 plane adapted for purpose, since some mortality resulted from fish striking sta- 

 bilizer and tail assembly of division plane. 



Report on the Second Airplane Fish-planting Tests in Mono County, Cali- 

 fornia. Submitted July 30, 1947. 8 pp., 1 table. 



Ahstrnct: The second series of airplane planting tests are described and 

 planting notes and observations are pre.'^ented and discussed. Free fall planting 

 is considered to be the method of choice for practical fish planting in High Sierra 

 lake.';. It is recommended that the Bureau of Fish CoiisHrvation proceed to have 

 designed and equipped a plane for fish planting in the High Sierras. 



