FUKTV-FIKST HIKNNIAL REPORT 55 



lf)45-46 season. This has been the result of increasing the total fishing 

 effort in the Eureka i-egion where prior to 1944 the resource had not been 

 fully harvested. During the same period more intense fisliing lias grad- 

 ually increased the seasonal landings at San Francisco to about five and 

 one-half million pounds which is about 2. ()()(). 0(10 |)()uuds al)ove the ])re- 

 war level. 



Crab traps of stainless steel wire woven about circular frames have 

 become the principal fishing gear. However, there are still many smaller 

 boats in both the San Francisco and Eureka regions contributing to the 

 total laiulings through the use of the hoo]i nets which once were the 

 mainstay of the fishery. 



Since there must exist a limit to the amount of exploitation of the 

 resource in relation to the natural ])roduction of the species, it became 

 advisable in 1!)48 to begin a biological investigation of the crab to deter- 

 mine if this resoui'ce can withstand the increased fishing pressure. 



The existing protection of females and the minimum size limit restrict 

 fishing to a definite group of older male crabs. When these are taken 

 crabbing must cease — but only until after the ensuing molting season 

 which brings in a new group of legal-size crabs, rreliniinary studies of 

 the present biological investigation are yielding information on the rate 

 of growth and size at first maturity of the crab in California waters. 

 Crabs about to shed their shells are liekl in fresh circulating sea water 

 at tlie Steinhart Aquarium, San Francisco. The growth of these crabs 

 after molting gives increments of the various sizes. The seasons of molt- 

 ing for different size groups are being ascertained and considered with 

 periodic growth increases to give data for construction of the desired 

 growth curve. Determination of the size and age at first sexual nuiturity 

 will allow an estimation of the possibility of the intensive fishing oper- 

 ations i-esulting in iiTeparable tlamage to the resource. There is indica- 

 tion that legal-size crabs have passed through two mating seasons. Thus, 

 it seems, since natural production has opportunity for success, that 

 only a catastrophe for the females or the young stages could harni the 

 fishery for an extended period. 



PISMO CLAM 



After Sejitember, 1!)47, there was no legal commercial exploitation 

 of California Pismo clams but limited quantities have been imported into 

 the State from Mexican waters to meet the consumer demand. During 

 1948 there were no records of shipments into California from south of the 

 International Boundary. In 1949, however, the imports amoiuited to 

 about 045,000 pounds live weight. Reduced canning is the major factor 

 responsible for the drop in importations from a high of over 58,000,000 

 pounds in 1945. 



In October, 1949, Fish and Game District ISA (the LeGrande sanc- 

 tuary just south of Pismo Beach ) was open to the sportsmen of the State 

 for the first time in 20 years. During a two and one-half month period 

 following this opening an estimated 4,000,000 pounds were removed 

 from this beach. At the same time that District 18A was opened, two 

 other areas (one at Pismo Beach and one at Morro Bay) were closed 

 to clam digging. It is anticipated that designated areas will be set up as 

 clam sanctuaries and alternately opened and closed approximately every 



