Table 29.— Proportions of females in the apparent yellowfin sole population by age group and geographical area, 1976 Bering 



Sea spring trawl survey. 1 















Age group (yr) 















AH ages 

 combined 



Subarea ! 



<3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 

















„ 

















Inner shelf 































4N 



0.51 



0.61 



0.62 



0.52 



0.57 



0.59 



0.65 



0.75 



0.58 



0.58 



0.62 



0.66 



0.81 



0.43 



0.59 



4S 



0.43 



0.52 



0.53 



0.52 



0.58 



0.61 



0.68 



0.76 



0.60 



0.58 



0.72 



0.69 



0.81 



0.27 



0.58 



1 



0.42 



0.61 



0.51 



0.51 



0.46 



0.42 



0.47 



0.53 



0.33 



0.36 



0.42 



0.56 



0.58 



0.57 



0.47 



Outer shelf 

































3 



— 



0.88 



0.59 



0.68 



0.60 



0.59 



0.62 



0.68 



0.51 



0.53 



0.59 



0.71 



0.71 



0.20 



0.62 



2 



0.50 



0.97 



0.58 



0.62 



0.56 



0.54 



0.57 



0.64 



0.43 



0.44 



0.56 



0.53 



0.61 



0.28 



0.57 



All subareas 

































combined 



0.44 



0.60 



0.54 



0.54 



(i -1 



0.48 



0.52 



0.58 



0.39 



0.41 



0.49 



0.58 



0.63 



0.37 



0.52 



'Based upon sampled individuals for which sexes could be determined. 

 2 See Figure 3. 



Table 30. — Length-weight relationships observed for yellowfin sole during the 1976 Bering Sea 

 spring trawl survey, with testing for between-area and betwetn-sex differences. 









TL 















Otolith 



Number 



range 



Length-weight coefficients 



Predicted weight 



■at-length 



Sex 



area 1 



sampled 



(cm) 



a 



b 



10 cm 



20 cm 



30 cm 

















grams 











Males 



A 



180 



9-33 



0.0226 



2.7504 



12.7 



85.5 



260.9 





C 



33 



16-27 



0.0044 



3.2909 



8.6 



84.7 



— 





Both areas 



















combined 



213 



9-33 



0.0208 



2.7790 



12.4 



85.6 



264.2 



Females 



A 



193 



10-37 



0.0195 



2.8197 



12.8 



90.8 



284.9 





C 



100 



17-34 



0.0058 



3.2162 



9.5 



88.9 



327.6 





Both areas 



















combined 



293 



10-37 



0.0168 



2.8698 



12.4 



91.1 



291.9 



Overall 





506 



9-37 



0.0172 



2.8532 



12.2 



88.7 



282.2 



Analysis 



of covariance 



















Slope 



(b) 



Common 



means 





df 



F ratio 



df 





F ratio 



Males between areas A and C 





1:209 



10.3** 



— 





— 



Females 



between area; 



! A and C 





1:289 



10.1" 



_ 





— 



Between 



sexes in area 



A 





1:369 



1.1 



1:370 





16.9 



Between 



sexes in area 



C 





1:129 



0.2 



1:130 





3.3 



'See Figure 4. 

















:*• 



= P «0.01. 

















the two estimates, the 1976 spring survey estimate may have been 

 biased high — similar to yellowfin sole — by effects of inshore 

 migration (Shubnikov and Lisovenko 1964). The distribution of 

 apparent population biomass during the 1976 survey was subarea 

 2, 46.9%; subarea 4S, 32.9% (resulting from high catch rates 

 along the subarea's western boundary); and subarea 1, 14.3% 

 (Table 32). 



The total number of rock sole within the study area (available 

 to the trawl) was estimated to be 928.9 million individuals, distrib- 

 uted among geographical regions similar to the apparent biomass. 



Size composition.— Rock sole ranged from 6 to 48 cm TL, with 

 an overall mean total length of 27.8 cm (based upon 10,561 field 

 measurements; Fig. 43). In general, the observed size-frequency 

 distributions were similar among all geographical areas. In all 

 areas, the frequency distributions for male populations were 

 shifted toward small sizes, with mean total lengths approximately 

 86% (range 85-90%) those of the female populations. 



Populations in subareas 4S and 2 Slope had the largest mean 

 total lengths (31.3 and 30.4 cm). Populations in subareas 1 , 2, and 

 3S showed smaller size distributions (mean total lengths 26.0, 



27.0, and 27.0 cm) due to relatively higher proportions of small, 

 young individuals ( < 24 cm). Particularly broad size ranges were 

 observed in subarea 2 (6-48 cm) and subarea 1 (12-47 cm). Trawl- 

 ing stations with high proportions ( > 50% of all rock sole taken) 

 of small ( < 24 cm) individuals were primarily located directly 

 north of the Alaska Peninsula, between Unimak Island and Port 

 Moller. 



Age composition. — Estimates of age-frequency distribution 

 were based upon an overall collection of 252 male and 451 female 

 saccular otoliths. The ranges in ages were males, 3-14 yr, and 

 females, 3-16 yr. The estimated number of individuals in each age 

 group (available to the trawl) are summarized in Table 33. 

 Overall, 79.4% of the apparent population was represented 

 within age groups 6-10 yr. 



Relative age distributions between geographical areas and sexes 

 are compared in Figure 44. In all areas, female populations were 

 relatively older than males; overall, 25.7% of females were older 

 than 10 yr, compared to only 2.0% of males. 



The proportional representation of each age group was quite 

 variable between different geographical areas. In subareas 4S and 



57 



