. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. 94 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 numb
. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. 94 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 his
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