-""S» 



Trout tagged on under side. 



(Fish and Game Photo by E. P. "Phil" Pister) 



providing an estimated 2,000,000 days angling and 

 1,500,000 fish to 150,000 anglers annually. 



During the biennium the system of postal card and 

 party boat catch reports has been maintained and im- 

 proved. An evaluation of the status of the fishery 

 based upon these records and data obtained through 

 special striped bass angler interviews and surveys was 

 made. It was shown quite conclusively that there has 

 been a gradual but decided decline in the total catch 

 and average angler success. Individual angler success 

 is now only about one-half w hat it was during tiie pre- 

 war years. 



Bass Size Limit 



In an attempt to improve the present quality of 

 angling a 16-inch minimum size limit and three fish 

 bag limit was recommended. These recommendations 

 were based on the biology of the striped bass and 

 angler catch records. 



The annual striped bass fry surveys, which indicate 

 spawning success and the distribution and abundance 

 of frv on the nursery grounds, w as continued. Spawn- 

 ing success in 1955 and 1956 appeared to be very poor 

 in comparison with 1953 and 1954. The distribution 

 of fry and fingerling bass is an important consideration 

 in relation to the large water diversions in the Delta 

 and in industrial pollution. 



Commercia/ Gill Netters 



During the biennium, project personnel investigated 

 the commercial salmon and shad gill netters in the 

 Delta to obtain estimates of the number of game fish 

 destroyed during normal commercial operations. The 

 study was conducted during the 1954 and 1956 shad 

 seasons and the 1955 salmon season. 



The investigations have shown that a greater num- 

 ber of bass are caught in the channel areas than in the 

 shallow flats of Honker and Grizzly Bays. However, 

 in the flats the percentage of striped bass in the catch 

 is almost twice that of the channels and the percentage 

 of mortality is also much greater. It is apparent that 

 the flats gill netters inflict the greatest relative amount 

 of damage in terms of fish destroyed per number or 

 poundage of marketable fish. 



Salmon catch figures have been computed for the 

 last 10 years. Since the loss of the San Joaquin spring 

 salmon run, the August 10th to September 26th 



commercial season provides about 97 percent of the 

 total annual river salmon catch. Gill netting for the 

 few salmon caught throughout the rest of the year 

 does not seem to justify the losses of bass caught in 

 gill nets. 



On the basis of the data brought out by these in- 

 vestigations the department is recommending addi- 

 tional measures to protect the sport fishes. 



In 1954 the taking of sturgeon on sporting tackle 

 was legalized for the first time in 37 years. The de- 

 partment felt that they were once again abundant 

 enough to support a hook and line fishery. 



Sturgeon Size Limit 



A sturgeon investigation was initiated to provide the 

 necessar\- data for the proper management of these 

 fish. A total of 1,003 white sturgeon were tagged in 

 San Pablo Bay. Tag returns indicate they are not 

 being overharvested by the anglers, although a con- 

 siderable number are caught by commercial gill net- 

 ters. The pattern of migrations has not yet been 

 \\ orked out in detail but there appears to be a general 

 tendencN' for them to move upstream in the late fall 

 and w inter. Two returns of San Pablo Bay were re- 

 corded from near the Columbia River in Oregon. 



A method of determining the age of sturgeon was 

 developed and an age and growth formula has been 

 computed. This study showed that the San Pablo Bay 

 population was principally composed of 6- and 16- 

 year-old fish. The fishery is apparently dependent 

 upon a few successful year classes. It was shown that 

 a size limit of 50 inches offers greater protection for 

 the fishery than 40 inches. Sturgeon do not mature 

 until the\- are 15 to 20 years old and should be given 

 protection at least to that size. 



Pollution Investigation 



Project personnel ran a series of bioassays on the 

 waste effluent from an industrial plant near Antioch 

 and found it to be quite toxic to fish life. Another 

 series of tests is being run on the effluent, using striped 

 bass as the test fish. As a result of these tests improved 

 standards were required by the Pollution Control 

 Board and plant waste discharges are noticeably 

 better. 



TROUT MANAGEMENT STUDY 



Nearh- all of the department's basic trout research 

 is now performed under the auspices of a single Din- 

 gell-Johnson (Federal Aid) project, which was en- 

 larged during the biennium to include work on 

 catchable trout evaluation. 



During the period, project activities were devoted 

 primarily to: (1) basic trout disease studies; (2) de- 

 veloping methods for the evaluation and improvement 

 of trout planting; (3) comparing difi^erent species and 

 strains of trout to determine which are the most suit- 

 able for the various types of California trout waters. 



