FORTY-THIRD BIENNIAL REPORT 



37 



(6) Brood Stock Selecfion 



The present strain of fall-spawning rainbow brood 

 stock used in the California hatcheries is known to 

 contain serious genetical \\'eaknesses, particularly 

 physical abnormalities. In order to rectify this condi- 

 tion a program of selection was begun in the fall of 

 1953 at the Alt. Shasta Hatchery. Some females were 

 taken at random from the stock, and in each case the 

 fish's eggs were divided into two parts; one part was 

 fertilized by one male and the other part by another 

 male. In turn each male was used to fertilize the eggs 

 of two females. These lots of eggs, 69 in all, were held 

 in separate trays until hatched. 



Twenty-four of the best appearing lots were then 

 retained for future brood stock. Data on fertility, 

 viability, appearance, growth rate, etc., were kept on 

 each lot. 



Several special studies were carried on in several 

 areas. Among these was a marked fish experiment on 

 Brush Creek, Tulare County, which showed the usual 

 small returns from stream-stocked rainbow fingerlings, 

 a large return to the angler from catchables, and an 

 even larger return from wild fish. 



Studies were started in Region V in an attempt to 

 discover what happens to "catchable" trout which are 

 not caught by the angler. The same experiments are 

 designed to show the effect of stream improvement 

 on catchable trout fishing. 



Trial plants of eastern brook fingerlings in Lake 

 Merced, San Francisco County, had only small returns 

 (although the fish grow well) by the close of the 

 biennium. 



Back-country Fish Management Study 



A total of 247 lakes, all lying in back-countr\' areas 

 of the Sierra Nevada and Siskiyou Mountain Ranges, 

 were examined as part of a Dingell-Johnson project 

 (F-3-R). Principal objectives were to evaluate current 

 management practices, to work out rapid evaluation 

 systems, and to put new or modified procedures into 

 effect. Special efforts were made to obtain data on 

 fish populations, spawning success, and angling use. 



The project crew made repeated eight- to ten-day 

 pack trips into back-country areas of the State, where 

 initial surveys and rechecks were made of lakes and 

 streams to develop sound management programs. The 

 problem of lake overpopulations by brook trout was 

 investigated, and routine equipment and methods were 

 retested. Results of work were observed, and several 

 chemical treatm.ent jobs were undertaken. 



Findings were discussed with management person- 

 nel, and assistance was given them in revising man- 

 agement policies. Planting allotments for back-country 

 waters were submitted annually as a part of this 

 survey program. 



Experimental improvement work was carried on 

 as a part of the field work wherever the crew was 



This pond, which will support small trout, was created by a rock dam 

 on McGee Creek, Mono County. 



able to handle the job with the tools at hand. Most 

 of the improvements consisted of consolidating stream 

 channels, removing rock or log barriers to spa\\ning 

 areas, digging out sod blocks in lake inlets, and con- 

 struction of rock dams. 



While this type of work was incidental to the 

 regular field activities, considerable benefits to the 

 lakes and streams were realized by these improve- 

 ments. For example, the removal of a log barrier in 

 one lake inlet, which required two hours' work, 

 opened up 600 yards of spawning area to the lake 

 rainbow population. It is very likely that no further 

 planting will be needed to maintain a satisfactory 

 population in this lake. 



On two occasions rotenone was used to treat back- 

 country lakes. One 10-acre lake was treated to re- 

 move eastern brook trout and rough fish preparatory 

 to rehabilitation with golden trout. 



In order to determine effects and desirability of im- 

 provement devices for possible use in mountainous 

 areas, 41 improvement structures on the East Fork 

 Kaweah River, Tulare County, were observed and 

 evaluated. The structures were built in 1935 by the 

 U. S. Forest Service. Twelve, all of log construction, 

 remain in operation after 18 years. Those of earth, 

 rock, masonry, plank and crib construction had been 

 destroyed. An evaluation report was submitted for this 

 study. 



Losses Investigated 



Reports of the loss of Piute cutthroat trout from 

 Cottonwood Creek, Mono County, due to floods were 

 investigated. It was found that the trout were not only 

 present, but they were well established as indicated by 

 size range and abundance. 



