FISHERY BULLETIN: VOL. 81, NO 4 



TABLE 5. — Contingency-table analysis of allelic frequencies of yellowfin sole of the North Pacific 

 Ocean and eastern Bering sea. Parentheses indicate non-orthogonal tests not included in the 

 totals. 



'/ 3 <0.01 



'0.05 > P < 0.01 



none of the among-sample comparisons for the Gulf 

 of Alaska were significant. At the next nested level, 

 the allelic frequencies of Ada-2 and Pgd were signifi- 

 cantly different (P<0.05) between the pooled Bering 

 Sea samples and the sample from Japan. The three-way 

 comparison between the pooled frequencies of the 

 Bering Sea, the Gulf of Alaska, and Japan was signifi- 

 cant (P<0.01) for each of the four polymorphic loci. 



Genetic Distance 



Among the Bering Sea and Japanese samples, D 

 ranged from 0.0002 to 0.0012 and averaged 0.0005 

 with an average standard error of 0.0003 (Table 6). 

 Similarly, for the Gulf of Alaska samples D ranged 

 from 0.0002 to 0.0008 and averaged 0.0005 with an 

 average standard error of 0.0003. However, the D's 

 between the samples from these two areas were much 

 greater than those within each region; they ranged 

 from 0.0029 to 0.0086, averaged 0.0049, and had an 

 average standard error of 0.0026. 



Gene-Diversity Analysis 



The results of the gene- diversity analysis are present- 



ed in Table 7. The average within- population diver- 

 sity (heterozygosity) ranged from 0.041 to 0.056 and 

 averaged 0.051. This represented 95.7% of the total 

 gene diversity. Of the remaining gene diversity, 3.6% 

 was due to regional differences between the Gulf of 

 Alaska, the Bering Sea, and the Japanese samples. 

 The proportion of the total gene diversity due to dif- 

 ferences among populations within each stock was 

 0.6% and that due to differences between the north- 

 and south-stock areas in the Bering Sea was 0.1%. 



DISCUSSION 



The results of this study show that there is little 

 genetic structuring of yellowfin sole populations 

 within the eastern Bering Sea or within the Gulf of 

 Alaska. Although tagging studies in the eastern Ber- 

 ing Sea reported by Wakabayashi et al. (footnote 4) 

 demonstrated that fish from the northern and 

 southern stock areas largely remained separated 

 during their annual inshore- offshore migration, there 

 appears to be sufficient migration between these 

 areas to prevent genetic differentiation. A similar 

 degree of migration between areas in the Gulf of 

 Alaska can be inferred from the lack of allele- 



Table 6. — Standard genetic distance (below diagonal) and standard errors (above diagonal) between 

 samples of yellowfin sole based on 31 protein-coding loci. Location numbers correspond to those in 

 Table 1 and Figure 1. 





674 



