The apparent number of individuals within each age group of 

 the sampled population (available to capture by trawling) is sum- 

 marized in Table 48. While the results presented in Table 48 may 

 be biased by sampling problems, the relative age-frequency 

 distributions shown in Figure 61 may still be fairly accurately 

 estimated, if biases were not age specific. 



Age groups 7, 8, and 9 yr accounted for 70.2% of the overall 

 apparent population. Although the relative age-frequency distri- 

 butions (sexes combined) were similar among all geographical 

 regions, subareas 4S and 4N showed the highest proportions of 

 young ( < 6 yr) individuals. 



Male and female populations differed in their apparent age- 

 frequency distributions in that females showed higher proportions 

 of both young (<6 yr) and old (> 10 yr) individuals, and their 

 predominant age groups were 8 (male) and 9 (female) yr. 



Sex ratio. — The overall observed proportion of females was 

 0.42 (Table 49). Males were more abundant than females in all 

 geographical regions except subarea 3S. Because of the limited 



number of age-length observations and questionable population 

 estimates, the data did not support a rigorous analysis of age- 

 specific sex ratios. There were no evident overall age-related 

 trends. 



Length-weight relationship. — A total of 148 individuals from 

 otolith area A were measured for total length and weight (Table 

 50, Fig. 62). The overall observed relationship (sexes combined) 

 was W = 0.0073 L 3 - 13 «. The length-weight relationships of male 

 and female populations significantly differed. Below 26 cm TL 

 (and within the observed size ranges), males were up to 4% 

 heavier at length than females. At > 26 cm TL, females were up 

 to 7% heavier at length. 



Age-length relationship and growth. — A total of 157 Alaska 

 plaice otoliths were collected in otolith area A. Mean total lengths 

 of age groups are summarized in Figure 63. The data were not 

 adequate to support mathematical fitting of growth curves. 



Table 48. — Estimated population size of Alaska plaice age groups and year classes within survey subareas of the eastern Bering Sea, 



1976 spring trawl survey. 1 



Subarea' 



£6 7 8 9 10 11 12 13 14 



— 1969 1968 1967 1966 1965 1964 1963 1962 



15 16 



1961 1960 



Age All ages 



unknown combined 



millions of fish 



Inner shelf 



4N 



4S 



1 

 Outer shelf 

 and slope 



3S 



3 Slope 



2 



2 Slope 



17.2 12.7 19.1 16.4 4.4 1.1 



(103.3) (71.8) (120.0) (114.2) (32.0) (7.7) 



(11.8) (26.1) (48.7) (48.9) (13.8) (4.0) 



2.7 



4.9 



9.4 



8.7 



2.3 



0.5 



1.1 

 (7.7) 

 (4.3) 



0.6 



0.6 

 (5.3) 

 (2.9) 



0.4 



0.1 

 (1.3) 



(0.7) 



0.1 — 



«0.1) 



0.6 



73.3 



(1.9) 



(465.2) 



(1.2) 



(162.4) 



(8.0) (23.4) (40.7) (35.9) (11.0) (2.0) (2.8) (1.2) (0.4) 



0.2 



(0.3) 



29.8 



(125.7) 



All subareas 



combined (143.0) (138.9) (237.9) (224.1) (63.5) (15.3) (16.5) (10.4) (2.6) — «0.1) 

 Proportion 



of total 0.167 0.162 0.278 0.262 0.074 0.018 0.019 0.012 0.003 - <0.001 



(4.2) 

 0.005 



(856.4) 



'Parentheses indicate estimates that may be badly biased due to sampling problems. The population in subarea 3N is not includ- 

 ed because no length-frequency data were collected. 

 'See Figure 3. 



Table 49. — Proportions of females in the estimated population of Alaska plaice by age group and geographical 

 area. 1976 Bering Sea spring trawl survey. 1 



Age group (yr) 



Subarea-' 



10 



11 



i: 



i? 



All ages 

 combined 



Proportion of females 



Inner shelf 



4N 



4S 



1 

 Outer shelf 



3S 



3 Slope 



2 



2 Slope 



0.50 0.34 0.35 0.57 0.49 1.00 0.52 0.05 1.00 0.45 



0.60 0.32 0.31 0.52 0.41 1.00 0.47 0.14 0.81 — 1.00 0.45 



0.08 0.09 0.17 0.47 0.45 1.00 0.60 0.10 0.54 — - 0.30 



0.78 0.39 0.44 0.63 0.48 1.00 0.48 0.30 0.81 — — 0.54 



0.57 0.36 0.34 0.53 0.48 1.00 0.47 0.03 0.38 — — 0.43 



All subareas 

 combined 



0.54 0.29 0.29 0.52 0.44 1.00 0.50 0.11 0.68 



1.00 



0.42 



'Based upon sampled individuals for which sexes could be determined. The population in subarea 3N is not 

 included because no length-frequency data were collected. 

 'See Figure 3. 



86 



