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DEPARTMENT OF FISH AND GAME 



Tagging catfish was one of the first steps in Dingell-Johnson Project F-2-R. It is being done to 

 determine migrations, to estimate fishing pressure and to obtain information about growth rates. 



A commercial fishery, primarily for white catfish and using fyke nets, 

 is also centered in the delta region. In recent years there have been de- 

 cided increases in the size and number of nets used and in the number 

 of fishermen. The landings have fluctuated quite widely, being around 

 400,000 pounds in 1951. 



There is now evidence of a general sort that the fishery has declined. 

 A real possibility exists that the species are being overfished by the com- 

 bined commercial and sport fishery, but adequate data are not at hand 

 either to substantiate or refute this hypothesis. Various forms of re- 

 strictive regulations (such as setting of size limits, seasons, and control of 

 gear) are continually being proposed. Again, we simply do not have 

 enough factual information to evaluate either the need for, nor the use- 

 fulness of, these or other measures. 



In addition to the need for adequate information on possible deple- 

 tion, and life history information which can be used for management, 

 we need to evaluate the effect of environmental changes caused by eco- 

 nomic encroachment. These include pollution and the effect of stream 

 diversion and impoundment. 



Our D-J project is now concentrating on the collection of such infor- 

 mation. We have started a tagging program intended to tag about 10,000 

 fish over a three-year period in order to determine movements, estimate 

 fishing pressure, and obtain information on growth rates. During the first 

 six months we tagged 3,466 catfish in the delta and had 73 tags returned. 

 An over-all history of the fishery and past regulatory practices is being 

 compiled. Life history material is being collected. Catch records are being 

 studied, and experiments on the effect of commercial gear will soon begin. 



