Sandholt Pier at Moss Landing, 2 feet below MLLW. On 19 May 1972, 29 

 small clams (14.1 to 35.4 millimeters long] were placed in the tubes and 

 retained in 2-millimeter-mesh covers. When the clams were recovered on 

 30 June 1972, some had been killed by fouling organisms which were 

 attracted to the mesh and had cut off water circulation to the interior. 

 The surviving clams were remeasured, the others substituted, and the 

 tubes were replaced by two plastic buckets without the mesh covering. 



On 20 December 1972, 33 small clams were recovered from these buckets. 

 The largest 17 clams were placed in the intertidal bed, and the other 

 16 were returned to the buckets with 98 newly marked small clams. 



On 20 January 1973, it was discovered that the cables had been cut 

 by vandals and the buckets lost. Ten days later, the buckets were 

 replaced with 64 clams in special racks at two new locations near the 

 pier. On 22 February 1973, it was determined that the waves had released 

 the buckets, losing all clams. A similar attempt in March met with the 

 same fate. The buckets with 34 clams were reestablished in strong metal 

 frames on 9 April 1973. On recovery, 8 May 1973, it was found that all 

 but one small clam had apparently been killed by two crabs that had 

 entered the buckets. An additional 50 newly marked clams were placed 

 in the buckets and covered with mesh to prevent entry of crabs. This 

 method worked well. Fifty clams on 3 June 1973 and 44 clams on 3 July 

 1973 were recovered, remeasured, and returned. 



Because of the small number of recoveries at each time interval from 

 the individual growth areas, and because of the losses due to weather and 

 vandalism, the data from each measurement period were combined. Therefore, 

 all recaptures from the intertidal, subtidal, and bucket sites were used 

 to figure rates for an> given interval of calculated growth rate. 



However, reasonable data were salvaged from the following time 

 intervals: 30 June to 9 August 1972; 11 August to 28 September 1972; 

 28 September to 26 October 1972; 26 October to 20 November 1972; 10 April 

 to 8 May 1973; 8 May to 3 June 1973; and 3 June to 3 July 1973. 



The data were analyzed in several ways. Plots of growth increment 

 against initial size were subjected to linear-regression analysis. Since 

 the time intervals in days were different among the sampling periods, the 

 instantaneous growth rate (Kg) was calculated for each interval (Simpson, 

 Roe, and Lewoutin, 1960). 



Finally, the age structure of the clam population at Monterey Bay 

 Academy was assessed, using a graphical analysis of size-frequency data. 

 This method (Harding, 1949; Cassie, 1954) involved plotting cumulative 

 percentages of each size clam on probability paper, and resolving the 

 result into the means and standard deviations of the age groups in the 

 population. 



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