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Fishery Bulletin 103(3) 



170°00 -180°00 -170°00 -160°00 -15CT0O -14OC0 -13(700 -120*00 



-110° CO 



-100° CO 



aim 



50° 00- 



-170° 00 



60° 00 



50° 00' 



-160° 00 



-150° 00 

 Figure 3 



-140° 00 



130° 00 



Proportions of Sebastes aleutianus and S. sp. cf. aleutianus in relation to depth of capture. 



Table 5 



Prevalence of parasites (percentage) in both rougheye rockfish types and results of categorical analysis of variance. 



Parasite prevalence 



sp. cf. aleutianus (n = 61) 



Neobrachiella robusta 

 Troehopus trituba 

 Corynosoma sp. 



0.57 

 0.49 

 0.90 



S. aleutianus (;i = 18) 



0.11 

 0.17 

 0.83 



Significance probability 



Type 



0.003* 

 0.022* 

 0.448 



Size offish 



0.442 

 0.339 

 0.326 



The Cavalli-Sforza-Edwards (CSE) chord distance 

 (for 29 loci) between the two S. aleutianus types, 0.35 

 (SD = 0.05), was a value comparable to that for other 

 closely related rockfish species. Seeb (1986) reported 

 CSE distances between rockfish species ranging from 

 0.07 to 0.75 for 28 loci. Identical mobilities at the ma- 

 jority of loci indicated a close relationship between 

 the two types, which probably existed as a single type 

 at an earlier geologic time. Given that Tsuyuki and 



Westrheim (1970) detected (2%) hybrids of the two 

 blood types and we did not detect fixed differences be- 

 tween the two rougheye rockfish types, some gene flow 

 may be occurring. However, the low effective number 

 of migrants and the sympatric distribution of the popu- 

 lation indicate that the gene flow is limited. Because 

 rockfish have internal fertilization, sibling species may 

 co-occur and there is little chance of cross-fertilization 

 of gametes. 



