Hawkins et al.: Genetic variation of Sebastes aleutianus and 5. borealis 



531 



-1.5 



• S. sp. cf. aleutianus 

 o S. aleutianus 



<9 



-1.0 



-0.5 



0.0 

 X 



0.5 



1.0 



1.5 



Figure 2 



Multidimensional scaling analysis of individual rougheye rockfish {Sebastes aleu- 

 tianus) genotypes for 25 loci. 



(South Tanaga Island Sebastes sp. cf. aleutianus type, 

 P=0.042, and North Unalaska Island S. aleutianus 

 type, P= 0.023). The G-test analysis indicated no hetero- 

 geneity among regions except for the Russian sample, 

 which was significantly different from all other samples 

 (P<0.05). Average heterozygosity was 0.09 for S. aleu- 

 tianus and 0.08 for Sebastes sp. cf. aleutianus. 



A significant difference in overall depth of capture 

 (P<0.001) was detected between Sebastes sp. cf. aleu- 

 tianus (mean 330+ m) and S. aleutianus (mean 208 

 m). We obtained both shallow and deep collections from 

 the central Gulf of Alaska. The fish captured at shal- 

 low depths, 77-249 m (regions 4-7, 9a, 9b, rc = 134), 

 were nearly all (94%) S. aleutianus, whereas the deep- 

 er dwelling fish, 270-600 m (regions 5a-7a, 8, 8a, 9, 

 n=204), were mostly (87%) Sebastes sp. cf. aleutianus. 

 Both types were captured, some within a single haul, 

 in southern Southeast Alaska (regions 2 and 3, /z = 89) 

 at depths of 150-260 m (Fig. 3). 



A highly significant correlation of fish length (15- 

 65 cm) and depth of capture (77-260 m) was detected 

 for S. aleutianus in Southeast Alaska, with smaller 

 fish in shallower water and larger fish in deeper water 

 (r 2 =0.415, P<0.001) No length-depth trend was noted 

 for Sebastes sp. cf. aleutianus. 



Results of the parasite analysis for the 2001 rougheye 

 rockfish showed that Sebastes sp. cf. aleutianus had a 

 significantly higher prevalence of both Neobrachiella 

 robusta (P=0.003) and Trochopus tntuba (P=0.022) 

 than did S. aleutianus (Table 5). 



Discussion 



The most notable conclusion of our study was that two 

 genetically distinct types of rougheye rockfish exist. 

 This conclusion corroborates prior biochemical studies in 

 which Tsuyuki et al. (1968) and Tsuyuki and Westrheim 

 (1970) conducted hemoglobin electropherogram analyses 

 on S. aleutianus and S. caenaematicus (=S. borealis) and 

 detected four blood types. Three blood types character- 

 ized S. aleutianus — two distinct types and a rare hybrid 

 type. The fourth type characterized S. borealis. Seeb 

 (1986) examined allozymes from several species of North 

 Pacific rockfish and found two color morphs of rougheye 

 rockfish fixed for alternate alleles at three loci. At one 

 of the loci, ACP*, we detected a small percentage of a 

 shared allele, likely because of our larger sample size. We 

 were unable to resolve the other two loci, GAP* (IUBNC 

 no. 1.2.1.12 Glyceraldehyde-3-phosphate dehydrogenase,) 

 and GAM* (B-Galactosaminidase). Although we are 

 unable to report fixed loci differences between the two 

 rougheye rockfish types, we did detect significant allele 

 frequency differences at nearly half of the loci examined. 

 Allelic mobilities of Sebastes aleutianus were similar to 

 those of Seeb's "Sebastes aleutianus," and allelic mobili- 

 ties of Sebastes sp. cf. aleutianus were similar to Seeb's 

 "Sebastes aleutianus unknown." Because simultaneous 

 hemoglobin and allozyme studies have never been done, 

 we are currently unable to correlate allozyme types with 

 the blood types reported by Tsuyuki et al. (1968) and 

 Tsuyuki and Westrheim (1970). 



