. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 536 Fisheries oceanography TABLE 33-5 Summary of mean lengths-at-age determined from NMFS Crab-Groundfish research vessel surveys conducted during June to mid-August, 1973-78 (units = cm fork length) Survey year Age-classes (yr) 7 8 9 10 11 12 13 14 15 1973 1974 1975 1976 1977 1978 - - - - 5
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder. Oceanography Bering 536 Fisheries oceanography TABLE 33-5 Summary of mean lengths-at-age determined from NMFS Crab-Groundfish research vessel surveys conducted during June to mid-August, 1973-78 (units = cm fork length) Survey year Age-classes (yr) 7 8 9 10 11 12 13 14 15 1973 1974 1975 1976 1977 1978 - - - - - - - - - - Xjj = a hypothetical age of zero size, and d = a dimensionless exponent reflecting ab- solute growth rate. The model vi^as fitted to the data by a computer program using a Taylor-series method for least squares approximation (Draper and Smith 1966). The results are shown in Figure 33-13, and the parameter values of best fit describing growth in length (sexes combined) were: y°o - cm K = Xo = yr d = In summary, the pattern of growth in length observed was fast growth between ages 1 and 5, relatively rapid decrease in annual length increments with increasing age, and an asymptotic body length of approximately 65 cm. To examine characteristics of growth in weight, the mean weights-at-age were approximated by applying a power relationship to the length data in Table 33-5. The relationship used was (Pereyra et al. 1976): W = L2-977 (3) where: W = estimated body weight in grams, and L = body (fork) length in cm. After converting the mean length of each age-class to a computed "mean weight," for all years, the overall mean weights (, column means) were de- termined, and the generalized growth model (Equa-
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