TWENTY-SEVENTH BIENNIAL REPORT. 71 



STRIPED BASS DECREASING. 



The annual commercial catch of striped bass in California shows a 

 decrease of about fifty per cent since 1915 and alonor with this decrease 

 in the commercial catch is a decided scarcity of bass in many of tlie 

 haunts where both anglers and commercial fishermen formerly found 

 them abundant. Tlie present scarcity is most noticeable in most parts 

 of San Pablo Bay and in the mouths of sloucrhs tributary to it. On the 

 other hand striped bass are apparently more plentiful in some other 

 places and good angling has been enjoyed in places where they had 

 Ijeen caught only in very limited numbers before. There are some 

 ardent striped bass anglers who believe that these fish are just as 

 plentiful as they ever were. Tliey believe that some of the sloughs 

 have been fished out by anglers but that in most cases the bass have 

 moved from their old haunts and have to be sought in other places. 

 Commercial fishermen say that the bass are about as luimerous as ('v<'r 

 but that they have moved and that the best net fishing is to be found in 

 places where the bass were formerly not so abundant. 



]\Iost bass anglers, however, are firmly of the opinion that the bass 

 are not only less plentiful but that they are on tlie road to exteniiiua- 

 tion. It is our belief after reviewing all the evidence that striped l)ass 

 are not so plentiful and that they are being over-fished at the present 

 time. 



It should not be argued that the falling off of the commercial catcli 

 shows that the bass are being fished out by the nets and that there are 

 less than half as many bass as in 1915. It is very much more likely that 

 the fifty per cent decrease in the commercial catch is almost entirely 

 due to the verj^ good restrictive legislation which has been ol)tained 

 through the efforts of the Fish and Game Commission and the commis- 

 sion's efficient enforcement of the protective laws. 



The usual method of protecting fish against over-fishing is to restrict 

 the catch and when efficient protective measures are adopted and 

 enforced the resulting decrease in the catch should not be used as evi- 

 dence that the fish are being exterminated. The scarcity of bass in 

 some of their old haunts about San Pablo Bay we believe is lartr('l.\ due 

 to the bass moving to other regions. This movement is largely dut- to 

 the pollution of San Pablo Bay waters by the government's dredging 

 operations about ]\lare Island and in deepening the channel from Mare 

 Island to Pinole Point. Much dredging has also been done about the 

 mouths of the more important sloughs. The continued stirrin«i of the 

 mud by dredging operations has caused the tides to carry great <|uan- 

 tities of silt over the bay and into the mouths of the sloughs where it 

 has settled to the bottom like a blanket and has pretty efl^'ectually kilhd 

 the diatoms and other plant life which form the basis of tlie food supply 

 of fishes. This condition was called to our attention ])y Dr. Albert 

 Mann of the Carnegie Institute after he had made a diatom survey of 

 San Francisco and San Pablo Bay waters. Dr. :\lann was alarmed l)y 

 the conditions he found in San Pablo Bay and stated that if we are to 

 preserve our fisheries we will have to guard against the blotting out of 

 diatom life by silt from dredging operations such as is takini; plaee in 

 our bays and rivers. There can be no doiil)t that the j)ollution of tlie 

 Avatersby sediment from the dredgers hns caused the ba.s.s to largely 



