12. PISH AND GAME COMMISSION. 



abandon their old haunts about San Pablo Bay. Oil pollution may 

 also be a contributing factor. 



The best evidence that striped bass are being depleted by fishing 

 operations is the growing scarcity of large individuals. This is one 

 of the surest signs of depletion and very nearly every one agrees that 

 there are fewer large bass. Striped bass need more protection but pro- 

 tection is more urgently needed in the case of the salmon. As these 

 two fish in the San Francisco Bay region are caught by the same fish- 

 ing methods and are to a large extent caught at the same time in the 

 nets, it is necesisary to protect both if we are to protect either, so striped 

 bass and salmon protectionists are proposing to get together and aid the 

 Fish and Game Commission in the better protection of the two fish. 



CLAM INVESTIGATION. 



Since our last report Fish Bulletin No. 4, entitled ''The Edible 

 Clams, Mussels and Scallops of California" by Professor F. AV. Wey- 

 mouth has been issued as a contribution from the State Fisheries Labor- 

 atory. This bulletin gives descriptions and illustrations of over forty 

 species of California clams and scallops, which are likely to have a 

 commercial importance, together with the localities where they are 

 found, their abundance and the condition of the beds. There is a 

 key which will enable any one to identify the species with but little 

 difficulty. The methods of our shellfish industries are given, together 

 with something of the habits of the more important species. Future 

 possibilities of forming and extending the beds^ of the introduced soft- 

 shell clam are diseussed. The need of state control of the tide lands 

 suitable for clam farming is also discussed. This is one of the 

 l^est bulletins the Commission has issued and it has attracted consider- 

 able notice and favorable comment. 



Since the j^ublication of this bulletin Mr. Weymouth has been 

 giving part of his time to the study of the Pismo clam, one of our 

 most important mollusks. This work was first begun in 1919 while cim- 

 pleting the survey for the bulletin above mentioned. A report on this 

 work has been submitted and soon will be issued as a bulletin. 

 Although the matter treated in the report is of high scientific value the 

 layman will find it very interesting. It will give the life history of the 

 clam; its habits, age, rate of growth and fluctuations in abundau'jie. A 

 census of the clams on the Pismo Beach, San Luis Obispo County, has 

 been made each year, which shows a remarkable fluctuation in the suc- 

 cess of each year's crop of clams. In that respect the bulletin will illus- 

 trate in a remarkably clear manner what is termed the natural fluctua- 

 tions in the abundance of year classes, Avhich in the conservation of one 

 of our fisheriers must be distinguished from fluctuations due to over- 

 fishing. It was found that, with the exception of the year 1919, the 

 spawning seasons of the past six or seven years have been comparative 

 failures. The census of the clams on the beaches show that the clams 

 of the 1919 year class, now in their third year, constitute 90 per cent 

 of all the clams to be found. 



For the purposes of conservation, the most important information 

 gained is that the clams during their first three years before they have 

 reached the best size limit, pass their life in the sand of the beaches 



