. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering New Alaska surf clam resource 1209 Estimates of standing stock Exploitable biomass estimates were calculated by survey block for the 1977 and 1978 resource- assessment surveys and for the two combined (Table 67-1). Although most survey blocks were assessed each year, work was not completed in blocks 44, 46, and 56 in 1977 nor in 40, 46, 54, 55, 58, and 61 in 1978. Thus the 1977-78 combined surveys pro- vided coverage of all blocks occupied by the resource, 40-65,
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering New Alaska surf clam resource 1209 Estimates of standing stock Exploitable biomass estimates were calculated by survey block for the 1977 and 1978 resource- assessment surveys and for the two combined (Table 67-1). Although most survey blocks were assessed each year, work was not completed in blocks 44, 46, and 56 in 1977 nor in 40, 46, 54, 55, 58, and 61 in 1978. Thus the 1977-78 combined surveys pro- vided coverage of all blocks occupied by the resource, 40-65, but because of these differences in geographic coverage total biomass estimates for 1977 and 1978 are not directly comparable. We believe the com- bined 1977-78 survey data provide the most accurate estimate of the described S. polynyma exploitable stock, 329,179 mt ± 52,000 mt of whole clams (95-percent confidence level). Production tests Production fishing tests were completed in 1978 at 13 sites along the north coast of the Alaska Peninsula (Fig. 67-1) to assist industry and management's evaluation of potential for a future commercial fishery. Table 67-2 summarizes catch-effort data and mean shell length of S. polynyma obtained at each production site. Weighted size and age composition of combined catches at all production sites (Fig. 67-6) represent the distribution of size and age expected in commercial harvests of the resource. 450 400 350 300 - 250 200 150 - 100 50 - 40 50 60 70 SO 90 100 110 120 130 140 150 Shell length (mm) Figure 67-5. Shell-length/round weight relationship of S. polynyma off the north coast of the Alaska Peninsula, 1977. - .. / /â .':â /â Alaska Surf Clam i 7' Antilog intercept = Slope = Sample size = 184 V "X?"" \ yf V i^"" 1 Growth Length-at-age data from the 1977 and 1978 surveys were fitted by the Von Bertalanffy relation 't ^ ^oo (1-e" (^'^0 ^), with computational procedures by Fabens (1965).
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