A sportfishing dock at Noyo Harbor, Fort Bragg. The small boats are 

 typical of those used by salmon fishermen in the ocean. 



(Fish and Game Photo by C. H. Meacham) 



5. To provide information for evaluating the 

 effects of proposed and existing water develop- 

 ments on salmon and steelhead in the north- 

 coastal portion of the State. 



Work Started in 1955 



During the biennium the growth of young steelhead 

 at Cedar Creek Station progressed as expected. Mark- 

 ing of approximately 170,000 fish at the station started 

 on December 19, 1955, and continued through Decem- 

 ber 21st, when torrential rains caused the river to rise 

 over the rearing ponds and wash away all the fish. 

 At that time 75,186 marked steelhead and approxi- 

 matelv 90,000 unmarked fish entered the river. 



At the close of the biennium approximately 500,000 

 voung steelhead were in the rearing ponds and the 

 losses from the flood had been replaced. 



A great deal of time was devoted to getting data 

 on the Trinity River for population estimates. This 

 information was needed in order to make recommen- 

 dation for facilities to maintain the important salmon 

 and steelhead fisheries in the face of the huge water 

 development project recently begun at this stream. 



flow Measurements 



Water flow measurements, in conjunction with 

 gravel analyses, were made to develop methods for 

 determining an optimum flow over a spawning area. 

 These methods are being applied in the Trinity River 

 and will be applied in the Eel River and other coastal 

 streams. Information on optimum water flows is essen- 

 tial, in order to recommend the proper water releases 

 from reservoirs constructed on salmon and steelhead 

 streams. 



Fish sampling on Alendocino coastal streams has 

 revealed that the present summer closure on these 

 streams is a sound regulatory measure. This closure 

 is designed to assure a maximum winter fishery for 

 adult steelhead and is serving its purpose well. 



SACRAMENTO-SAN JOAQUIN STUDY 



The Inland Fisheries Branch began a study in 1953 

 of the salmon and steelhead of the Sacramento and 

 San Joaquin Rivers, financed mainly by federal funds. 

 The Marine Fisheries Branch, the U. S. Fish and Wild- 

 life Service and sportsmen's organizations have par- 

 ticipated in the work, various phases of which were 

 nearing completion at the close of the biennium. 



The study has two principal goals. The first is the 

 evaluation of salmon and steelhead losses in the nu- 

 merous irrigation diversions in the Sacramento and San 

 Joaquin Valleys. Information gathered to date is 

 already being used as a guide to the economic justifi- 

 cation of fish screens at various sites, and to set up 

 fish screen priority lists for diversions in which salmon 

 and steelhead are being destroyed. 



The second goal is to determine the effectiveness 

 of supplementing natural steelhead production in the 

 Sacramento River system with hatchery-reared fish. 

 Facts obtained will form the basis for a sound man- 

 agement plan for steelhead trout in the upper Sacra- 

 mento River. 



Fish Losses Evaluated 



During the previous biennium, \\ ork was performed 

 on irrigation diversions along the Sacramento River 

 between Redding and Sacramento. It was found that 

 losses of seaward migrant king salmon fingerlings, 

 though present through most of the irrigation season, 

 were relatively small because most of the young sal- 

 mon migrate into the Delta before the normal irriga- 

 tion season gets into full swing in late April and early 

 May. 



However, evidence shows that if the irrigation 

 season started earlier, for example in early iMarch, con- 

 siderable losses would occur. It was also demonstrated 

 that serious losses of adult salmon and steelhead occur 

 at pump intakes lacking trash grids or screens. 



Delta Investigation 



During the 1955 irrigation season, work was shifted 

 into the San Joaquin Valley and into the Sacramento- 

 San Joaquin River Delta. Here, between the middle of 

 March and the last of May, eight typical large diver- 

 sions were sampled for fish losses. These diversions 

 included three located along a 43-mile stretch of 

 the San Joaquin River between Stockton and Pat- 

 terson, four in the Delta between Antioch and Rio 

 Vista, and one on the Mokelumne River near Wood- 

 bridge. Losses of fingerling king salmon at irrigation 

 diversions along the San Joaquin River were much 

 greater than at those sampled along the Sacramento 

 River. This is due for the most part to an earlier irri- 

 gation season in the San Joaquin Valley, when the 

 fields are being flooded as the peak of the seaward 

 migrant salmon run is passing. One of the larger diver- 

 sions near Stockton was found to have taken over 

 20,000 young salmon in late March and April alone. 



Bufte Creek 



Work in 1956 centered on Butte Creek, an impor- 

 tant tributary of the Sacramento River. Eight large 

 diversions are present along a 25-mile section of this 

 stream; one was screened experimentally. It is essential 

 that they be evaluated with respect to fish losses before 

 a screening program is developed. However, due to 

 floods during the previous winter, no young salmon 



