FORTY-THIRD BIENNIAL REPORT 



67 



NEW CLAM FISHERY 



Possibility of a new clam fishery in Morro Bay has 

 developed as a result of the 1953 transplanting of 

 Japanese littleneck clams from San Francisco Bay to 

 Southern California waters. Because of harbor dredg- 

 ing as well as clam digging, the various species of 

 littleneck clams became quite scarce in Southern Cali- 

 fornia bays, and the department planted 6,000 of the 

 Japanese littlenecks, 4,000 at Morro Bay and the re- 

 mainder at Newport Harbor. 



At least half of those planted at Morro Bay lived 

 and showed remarkable growth during their first year. 

 From all appearances these should spawn during 1954, 

 and if successful there may soon be a new fisher\' 

 where none existed before. Clams planted in Newport 

 Harbor were placed in deeper water and no observa- 

 tions on their progress have been possible. 



Pismo clam censuses conducted at Pismo Beach and 

 Morro Bay during 1951 and 1952 indicated a continu- 

 ing shortage of young clams at both locations, appar- 

 ently the result of very poor sets during the past 

 several seasons. However, the number of legal clams 

 in closed areas or clam sanctuaries has increased con- 

 siderably each year, showing that short-term closures 

 do assist materially in building up a supply of legal- 

 sized clams. Information of the 1952 and 1953 cen- 

 suses was published in April of 1953. 



Clam Mortality Investigated 



Department biologists investigated reports of an 

 alleged set of Pismo clams in Morro Bay, the young 

 of which were supposedly dying. People of the area 

 were considering transplanting them to a more favor- 

 able habitat, a project involving tremendous expense. 

 Department biologists determined that the "baby 

 Pismo" clams were not Pismo clams at all, but a 

 variety having no common name, and which never 

 attains a size greater than a quarter of an inch, and 

 which never lives more than one year. 



During the fall and winter of 1953-1954 the labora- 

 tory was asked to identify a species of clams which 

 was blocking irrigation pipelines in the Imperial and 

 Coachella Valleys, and was incurring considerable ex- 

 pense to farmers. This was found to be the same 

 species of fresh water clam, Corbicida flmnhiea, which 

 had become established in the Sacramento-San Joaquin 

 drainage within the past decade. An oriental species, 

 its introduction into California can only be surmised. 

 Its spread is best attributable to the army of small 

 boat-owning fishermen and hunters traveling from one 

 river system to another with bait buckets and bailing 

 cans unknowingly filled with the microscopic larvae 

 of this prolific clam. 



THE ABALONE FISHERY 



Although the commercial abalone catch dropped 

 slightly from the previous biennium it still remained 

 above 4.7 million pounds. Among the highlights of the 



period was the emergence of developments in the div- 

 ing field, both with conventional gear and with the 

 aqua-lung. These developments played an important 

 part both in the commercial catch and in investigations 

 being conducted by the Branch of Marine Fisheries. 



In Southern California, where the industry is con- 

 centrated in the Channel Islands, some of the commer- 

 cial divers were forced to descend well over 100 feet 

 to reach abalones of sufficient size and abundance. An 

 interesting development as a result of this deep diving 

 has been the appearance of a new species of abalone in 

 the catches. So uncommon is this abalone that it has 

 not been definitely classified. 



The abalone investigation has continued operations 

 during the biennium with the major area of effort con- 

 centrated along the north coast. Since the greatest 

 single problem is to determine how the population of 

 abalones in the intertidal zone is replenished, principal 

 efforts have been directed along this line. The tagging 

 program, which was an attempt to approach this prob- 

 lem, is being continued. 



Survey North Coast 



A setback suffered by the investigation was the loss 

 of the mother ship, Broadhlll. This vessel sank during a 

 storm while tied to the dock. She was refloated but 

 had suffered considerable damage, and will be replaced 

 with a larger and more seaworthy vessel. The depart- 

 ment has purchased the Nmitihis, a former 50-foot 

 northern drag fishing boat which is being modified 

 for adaption to the needs of marine research. When 



The diving boat Mollusk, used in the department's abalone investiga- 

 lioni. Bottles in foreground are used to re-KII aqua-lung tanks. 



