52 



DEPARTMENT OF FISH AND GAME 



little growth in 1956 while in competition with the 

 swarming crappie, they grew better than an inch a 

 month in 1957. The relatively inexpensive fingerlings 

 stocked in January put on such good growth they 

 provided more than half of the trout caught from mid- 

 July on through the fall. 



Bridgeport Reservoir, Mono County, was chemi- 

 cally treated in October, 1955, ^\'hen the reservoir \^'as 

 at an extremely low level, to remove a large popula- 

 tion of carp. Unusually heavy runoff during the winter 

 and spring of 1955-56 filled the reservoir for the first 

 time in \ears and provided excellent water conditions 

 for the fingerling and catchable-size rainbow trout re- 

 stocked into the reservoir in the spring and summer 

 of 1956. Fishing was surprisingly good in the late part 

 of the 1956 season and was phenomenally good in 

 1957, when limit catches of I'/z- to 2-pound average 

 rainbows were the rule. Trout growth in the carp-free 

 water was so excellent that subcatchable-size rainbows 

 stocked in the spring of 1958 provided the Bridgeport 

 area's best fishing during the summer and fall. The 

 improved fishery was quickly reflected in increased 

 angler activity. Prior to the treatment, Bridgeport 

 Reservoir normall>- attracted 30 to 40 boat-fishing 

 parties for opening day. On opening day of 1958 more 

 than 700 boats were on the reservoir. 



FLOW MAINTENANCE 



Rutherford Lake Flow Maintenance Dam was com- 

 pleted with Wildlife Conservation Board funds during 

 1956. This dam and Lillian Lake Dam assure a flow 

 in the West Fork Granite Creek, Madera County, 

 during late summer periods. Cow iMeadow Dam was 

 rebuilt and two saddle dams were repaired on Cherry 

 Creek in Emigrant Basin, Tuolumne County. 



Flow-measuring weirs were built below five lakes 

 in Emigrant Basin so that releases can be measured 

 each >"ear to keep Cherry Creek flowing with stored 

 water. 



Highland Lake Dam, El Dorado County, was com- 

 pleted to improve flows in the Rubicon River. A 

 debris-clearance crew removed unsightly snags, the 

 remains of trees killed by raising the lake levels at Big 

 Downey Lake, Nevada County, and at Buck Island 

 and Rockbound Lakes, El Dorado County. A lake 

 level maintenance dam was constructed on Wheeler 

 Lake, Alpine County, to deepen it and prevent peri- 

 odic winter kills. Investigations have been continued 

 to find new places where stream flow maintenance 

 dams are needed. Good dam sites are becoming scarce, 

 and it appears that the flow-maintenance dam program 

 in many areas is almost complete. 



The Southern California stream improvement pro- 

 gram, made possible b>- Wildlife Conservation Board 

 allocations, was completed at the end of the biennium. 

 The chief function of this project was to create addi- 

 tional pool areas in Southern California streams. Dur- 



ing its last two years of operation this project con- 

 structed 71 new stream improvement devices. 



KOKANEE SALMON 



The first salmon spawning run in the history of 

 Southern California's San Bernardino Mountains area 

 ended at Lake Arrowhead in late December, 1957, and 

 the department collected an additional half million 

 kokanee salmon eggs as the result of it. 



The fertilized eggs were placed in troughs at the 

 DFG's San Joaquin Hatchery, near Fresno, from 

 which the bulk of the resulting salmon fry were 

 restocked into Arrowhead early the following spring. 



The kokanee is a small-sized, land-locked strain of 

 sockeye salmon and, like all true Pacific salmon, inev- 

 itably dies after spawning. 



In Lake Arrowhead, where 200,000 fry were experi- 

 mentalh' introduced in April of 1955, the kokanee 

 reached 10 inches in length in two years and produced 

 phenomenally good fishing in the spring of 1957. 

 They averaged 12 to 14 inches in length when they 

 spawned in December, 1957, in their third year. 



The spawning run at Arrowhead was triggered by 

 mid-December rains that turned the lake's nearly dry 

 tributaries into sizable streams. Since eggs deposited 

 in the streams would be left high and dry when the 

 streamflow dropped, a DFG crew netted the spawning 

 fish and took every egg they could get. Eggs stripped 

 from the female kokanee were fertilized with milt 

 from the males and each day's take was rushed to 

 San Joaquin hatchery. 



If all goes well. Lake Arrowhead should again have 

 good kokanee fishing by late fall of 1959 or early 

 spring of 1960. The lake's trout fishing will continue 

 as usual and the relatively few kokanee that did not 

 mature in 1957 will be there for catching in 1958. 



WARMWATER FISHES 



The major effort of the statewide warmwater re- 

 search program was directed toward the evaluation of 

 the threadfin shad introduction into the Colorado 

 River. The shad, imported from Tennessee in 1953 

 and planted in the Colorado River in 1954, was ex- 

 pected to supply sorely needed forage for largemouth 

 bass and other warmwater game fishes. 



Much field and laboratory work connected with 

 the shad investigation was completed during the bi- 

 ennium. The results demonstrated that the shad helped 

 both the game fish populations and fishing success in 

 Lake Havasu on the Colorado River. The largemouth 

 bass responded to the shad with an increased growth 

 rate and better survival. The average increase in 

 growth for bass was about two inches for each year 

 of life. 



The black crappie fishery in Lake Havasu was 

 stimulated greatly by the shad. Prior to 1955, crappie 



