TABLE 1. — Number of bushels of surf clams processed, mean 

 weight tpoundsi of useable meats per bushel, and mean surface 

 seawater temperature at Kiptopeke Beach by months in 1974 

 and 1975. 



Number of 

 bushels 



Mean useable 

 meat bushel 



Mean seawater 

 temperature ( C) 



Month 



1974 



1975 



1974 



1975 



1974 



1975 



Jan. 19.736 18,225 



Feb. 11.791 18,489 



Mar. 13.450 8,237 



Apr 14,415 23.725 



May 19.020 39,130 



June 12,981 30.049 



July 8.328 19.488 



Aug. 10.140 23,930 



Sept. 14.430 23.038 



Oct. 14,558 29,136 



Nov 13,388 8,407 



Dec 15,327 28,316 



Total 167,564 270,170 

 Annual mean yield bushel 



11.7 



123 

 12.3 

 13.3 

 138 

 13.9 

 140 

 14.0 

 12.0 

 114 

 10.8 

 10.8 



1252 



10.6 

 11.3 

 12.7 



13.2 

 12 9 

 137 

 14.5 

 13.7 

 13.2 

 12.4 

 11 8 

 111 



12 59 



6.7 



56 



84 



12.2 



176 



21.7 



248 



250 



229 



16.2 



122 



68 



5.9 



5.7 



6.7 



98 



17.1 



22.5 



24.6 



266 



232 



19.5 



14.0 



76 



Virginia surf clams is from about May or June 

 through August. Loesch 2 reported a size range of 2 

 to 18 mm for young-of-the-year surf clams in early 

 October 1974 and estimated their age ranged from 

 1 to 4.5 mo. Thus, spawning in 1974 occurred from 

 at least June through early September. 



The regression of MMUWB on MMST for the 

 1974 data by the four models resulted in the fol- 

 lowing equations: 



Wald's AM regression: W = 10.1 + 0.102 C 



Bartlett's AM regression: W = 11.0 + 0.101 C 



flicker's GM regression: W = 10.0 + 0.168 C 



Principal axis: W = 10.9 + 0.108 C 



where W = MMUWB; C = MMST (degrees Cel- 

 sius); and the first and second values are the inter- 

 cept and regression coefficients, respectively. 



Predicted MMUWB values in 1975 and their 

 respective AMUWB are presented in Table 2. 

 Analysis of variance (Table 3) indicated a sig- 

 nificant difference among the predicted and ob- 

 served AMUWB values (P<0.001). The Student- 

 Newman-Keuls multiple range test indicated that 

 the only significantly different AMUWB was that 

 associated with the predicted MMUWB estimates 

 derived from Wald's AM regression. Thus, the 

 other three regression models predicted the 

 AMUWB with equally acceptable precision. 



The total useable meat yield obtained from the 

 270,170 bushels of surf clams processed in 1975 

 was 3,425,654 lb (1,554 metric tons). The sum of 

 the products of MMUWB and monthly landings 



2 Loesch, J. G. 1975. Inventory of surf clams in nearshore wat- 

 ers from Cape Henlopen to the False Cape area. Final Rep. 

 03-4-043-357, U.S. Dept. Commerc, Natl. Mar. Fish. Serv., 

 State-Fed. Fish. Manage. Prog. 



TABLE 2. — Mean monthly useable meat weight (pounds) per 

 bushel for Virginia surf clams in 1975 estimates by four regres- 

 sion models. 



Month 



AM 

 (Wald) 



AM 

 (Bartlett) 



GM 

 (Ricker) 



Principal 

 axis 



Jan 

 Feb. 

 Mar. 

 Apr. 

 May 

 June 

 July 

 Aug. 

 Sept 

 Oct. 

 Nov. 

 Dec 



Annual mean 

 yield bushel 



10.7 

 10.7 

 10.8 

 11 1 

 11 8 

 124 

 126 

 12.8 

 12.5 

 12.1 

 11.5 

 10.9 



11.65 



11.6 

 11.6 

 11.7 

 12.0 



12.7 

 133 

 13.5 

 137 

 13.4 

 130 

 12.4 

 118 



12.55 



11 



11 



11 1 



11.6 



129 



138 



14.1 



14 5 



139 



13.3 



124 



113 



12.57 



11.5 

 115 

 11.6 

 12 

 12.8 

 133 

 13.6 

 13.8 

 13.4 

 130 

 12.4 

 117 



12.55 



TABLE 3. — Randomized block analysis of variance of the 1975 

 observed and predicted mean monthly useable meat weight 

 (pounds) per bushel replicated by months. 



•P- 0.001 



for all three acceptable models estimated the total 

 useable meat yield with an error =£0.5%. For all 

 practical purposes the estimate could have been 

 made by using the 1974 AMUWB of 12.5 lb. Total 

 useable meat estimated with this constant was in 

 error by only 1.4%. However, because of seasonal 

 changes in body weight, monthly total useable 

 meat yields should be derived from the MMUWB 

 predicted by one of the acceptable regression equa- 

 tions. 



The observed AMUWB for the pooled data of 

 1974 and 1975 is 12.55 lb and can be used if only 

 annual estimates of useable surf clam meat yields 

 for Virginia stocks are desired. If a substantial 

 change in seasonal harvesting occurred, e.g., a 

 closed season, one of the acceptable regression 

 equations should be used until a new AMUWB 

 constant is estimated. 



Barker and Merrill (1967) reported losses of 11 

 to 20^ in body weight with the removal of the 

 viscera from New Jersey surf clams. However, 

 they sampled in May and November when the 

 gonadal portion of the viscera is not near its 

 maximum weight. The present data indicate that 

 the reported DSMN yearly landing weights, based 

 on 17 lb of meats per bushel, must be reduced by 

 26^ to more accurately ascertain the weight of 

 Virginia surf clam meats actually shipped to mar- 

 ket. 



641 



