56 



DEPARTMENT OF FISH AND GAME 



Striped bass. 



-Fish and Game Photo 



that can be used as a basis for evaluating future changes 

 in the fishery. 



One group of data concerns the tow net surveys that 

 have been made annually since 1953 in an attempt to 

 develop a technique that will provide an index of 

 annual spawning success. The 1953-1956 surveys were 

 carefully analyzed, and several deficiencies were dis- 

 covered. The 1957 and 1958 surveys were modified to 

 overcome some of the deficiencies, but the evaluation 

 is continuing, since the surveys are not fully perfected. 

 The 1957 and 1958 surveys indicated that spawning 

 success continued to be far below what it was in 1953 

 and 1954. 



An annual fall seining survey for juvenile stripers 

 was initiated in 1956 to obtain an independent estimate 

 of spawning success as part of the evaluation of the 

 tow net surveys. 



Most of the 1957-58 Fiscal Year was devoted to 

 planning and starting a three-year striped bass tagging 

 studv. The primary purpose of this study is to estimate 

 the proportion of the bass population that anglers 

 harvest each year and the proportion that dies annually 

 from natural causes. The study will also serve to sup- 

 plement information about bass migrations. 



The initial tagging for this study was done in April 

 and May of 1958. A total of 4,378 bass were tagged in 

 the delta near Antioch, and 891 were tagged in the 

 Sacramento River at Knights Landing. A reward tag 

 program was incorporated in the study in order to 

 get an estimate of the number of anglers not returning 

 tags from fish that they catch. Some preliminary results 

 from this study will be available in the summer of 1959. 



The project has also started a striped bass age and 

 growth study to determine whether environmental 

 changes have affected the growth rate in the last 30 

 years. Most of the data needed have been collected 

 and the analysis was under way at the end of the 

 biennium. 



STURGEON 



No new sturgeon investigations were started during 

 the biennium. The sturgeon fishery continued to be 

 of minor importance in the state, partially because no 

 effective angling methods have been found. Most 

 sturgeon are caught accidentally while anglers are fish- 

 ing for other species. 



The final results from the 1954 sturgeon tagging 

 study were analyzed. There are two particularly sig- 

 nificant results: 1. Only 2 percent of the tags were 

 returned by anglers during the first year of the study, 

 and another 0.6 percent since then; 2. One of the 994 

 white sturgeon tagged and three of the 25 green stur- 

 geon tagged have been recovered in Oregon. There- 

 fore, it is obvious that anglers harvested a very small 

 proportion of the San Pablo Bay white sturgeon popu- 

 lation, and that there is an interchange among the 

 white and green sturgeon populations of California 

 and Oregon. 



Tagging o striped bass in the department's current striped bass studies. 



— S. F. News Photo by Eddie Murphy 



