FORTY-THIRD BIENNIAL REPORT 



39 



sturgeon are once again abundant enough to support 

 a fishery. These fish have been heavily protected since 

 1917. On the basis of departmental recommendations 

 the Fish and Game Commission adopted an open sea- 

 son on sturgeon angling for 1954. 



Sacramento-San Joaquin River Salmon 

 and Steelhead Study 



This important federal aid project (F-7-R), begun 

 during the biennium, is presently aimed toward two 

 important objectives. The first is an evaluation of the 

 anadromous fish losses occurring at the numerous 

 water diversions in the Central \^alley. Second is the 

 derivation of a sound and practical management plan 

 for the steelhead trout of the Sacramento River. Valu- 

 able data are also being gathered on king salmon, as a 

 service to the Marine Fisheries Branch. 



Work on the diversions has thus far been confined 

 chiefly to the 246-mile section of the Sacramento 

 River between the Cities of Redding and Sacramento, 

 in which there are more than 300 points of diversion. 

 All but one are pumping diversions, consisting of from 

 1 to 13 pumps and ranging in capacity from less than 

 one to more than 2,300 cubic feet per second. 



During the 1953 irrigating season initial surveys 

 were made of each pump. Included was all the basic 

 information on factors believed to influence fish losses, 



such as periods of operation, depth and position of 

 intake, size and type of pump, etc. Notes were also 

 made on whether or not the pump could be effectively 

 tested for fish losses. Preliminary sampling was also 

 done at several diversions. 



With this phase of the work completed, several rep- 

 resentative pumps are being tested with fyke nets 

 through the 1954 irrigating season. Nets are placed in 

 discharge outlets of the pumps. At the end of the sea- 

 son reasonable accurate estimates may be made of total 

 numbers and species of fish lost through these pumps. 

 Similar pumps may then be evaluated on the basis of 

 these findings. 



Results to date indicate that loss of seaward migrat- 

 ing king salmon fingerlings through diversions in the 

 Sacramento-Redding area of the river is small, mainly 

 because the majority of the young salmon migrate 

 from this area during January, February, and March. 

 Heavy irrigation does not normally begin until several 

 weeks later. Observation of one 20-inch pump in Co- 

 lusa County revealed that a loss of considerable mag- 

 nitude can occur when there is early irrigation. At 

 this pump over 1,200 young salmon were captured 

 when the discharge was strained with fyke nets for 

 200 hours early in March. This is a much higher 

 figure than the combined take of this and several other 

 similar sized pumps during the entire month of May. 



A steelhead is returned to the Sacramento River after being lagged near Fremont Weir. Inlormalion on numbers and migrations of salmon and 



steelhead are obtained. 



