1094 



Loesch, Joseph G. 1974. 



A sequential sampling plan for hard clams in lower Chesapeake Bay. Chesapeake 

 Sci. 15(3) : 134-139. 



Using a relatively small hydraulic tow dredge, densities of Meraenaria 

 meraenaria were estimated at 3 stations in the York River, Va. One was 

 classified as a high-density area after 2 standard tows, one as medium- 

 density after 8 tows, and one as low-density after 6 tows. An average of 

 4.2 tows/station was required to classify 167 sites. This represented a 

 considerable saving of effort over a fixed, predetermined sampling plan. 

 The sequential sampling plan was constructed easily from limited a priori 

 knowledge of hard clam abundance and the fishery. Such a plan can be used 

 to monitor relative abundance, with considerable saving of time over more 

 detailed surveys. - J.L.M. 



1095 



Loesch, Joseph G. 1977. 



A comparison of frequency distributions of hard clam, patent-tong catches. 

 Chesapeake Sci. 18(1): 79-80. 



A commercial patent-tong fishery for Meraenaria meraenaria operates in the 

 York River, Va. Fishermen believe that catches have declined. The reality 

 of this contention was tested by comparing frequency distributions of 

 standardized catches in 1963 and 1972. The only difference was that 

 occasional large catches made in 1963 exceeded highest catches in 1972. 

 Although average catch was slightly lower in 1972, median catch increased. 

 When the data were analyzed by the Kolmogorov-Smirnov two-sample test, the 

 only difference was reduced range and smaller variance of 1972 catches. Views 

 of clammers were not substantiated. - J.L.M. 



1096 



Loesch, Joseph G., and Dexter S. Haven. 1973. 



Preliminary estimates of growth functions and the size-age relationship for 

 the hard clam, Meraenaria meraenaria, in the York River, Virginia. Proc. 

 Natl. Shellf. Assn. 63: 3 (abstract). 



Two groups of hard clam ranging from the smallest size practical for in- 

 dividual marking through the larger sizes (approximately 30-90 mm in length) 

 were measured, code-marked and planted in similar natural substrates at two 

 locations in the York River. Both groups have been harvested, remeasured, 

 and planted annually, and growth functions determined from length increments. 

 - authors' abstract - D.L. 



1097 



Loesch, Joseph G., and Dexter S. Haven. 1973. 



Estimated growth functions and size-age relationships of the hard clam, 

 Meraenaria meraenaria, in the York River, Virginia. Veliger 16(1): 76-81. 



Hard clam 30-90 mm long were marked and planted in 2 experimental plots, one 

 on each side of the River. An indelible Felt Riter pen produced marks that 

 lasted up to 3 yrs. Clams were recovered about once a year, measured, and 

 replanted. Substrate was sand -mud with scattered shell. Depth was about 7 ft 

 at MLW. Growth functions were derived by the Walford transformation method 

 (regression of year x+1 on year x) . Growth was more rapid in 1968-69 than 

 in 67-68 or 69-70. Growth functions in 67-68 and 69-70 were approximately 

 Y = 12 + 0.85X, in 68-69 of the order of Y = 18.6 + 0.766X. Calculated 

 asymptotic sizes were 79-82 mm. These were believed to be too low. Relatively 

 low salinity was suspected as the major factor limiting growth. Estimated 

 asymptotic growth sizes would not be reached until age 22 yrs, but for all 

 practical purposes growth ceases at 14 or 15 yrs. It was estimated that 

 clams in this area would not reach littleneck (legal) size until 4 yrs nor 



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