Blaylock et al : Use of parasites in discriminating stocks of Htppoglossus stenolepis 



Table 4 



Cross validation results of a four-category discriminant 

 function classification of adult Pacific halibut in the 

 northeast Pacific based on parasite data. Numbers of fish 

 assigned to a category and the corresponding percentage of 

 the sample in that category are shown. Correct classifica- 

 tions are shown in bold (63% of 240). OR-SQC = Oregon- 

 northern California to southern Queen Charlotte Islands, 

 NQC-KP = northern Queen Charlotte Islands to Kenai 

 Peninsula, KI-SB = Kodiak Island to southern Bering Sea, 

 PI-SMI = Pnbilof Islands to St. Matthew Island. 



True 

 category 



OR-SQC 

 NQC-KP 

 KI-SB 

 PI-SMI 



Assigned category 



OR-SQC NQC-KP KI-SB PI-SMI 



60 

 79% 



3 



5% 



7 



9% 



3 



4% 



28 

 50% 



23 



30% 



1 



3% 



7 

 9% 



21 



42% 



41 

 53% 



6 



20% 



6 



8% 



4 



7% 



7 

 9%. 



23 



77% 



Table 6 



Cross validation results of five-category discriminant 

 function classification for juvenile Pacific halibut in the 

 northeast Pacific based on parasite data. Numbers of fish 

 assigned to a category and the corresponding percentage 

 of the sample in that category are shown. Correct classi- 

 fications are shown in bold (44% of 62). NQC = northern 

 Queen Charlotte Islands, NI = Nagai Island, UP = Unimak 

 Pass, and PI = Nunivak Island (central Bering Sea). 



True 

 category 



NQC 



KI 



NGI 



UP 



PI 



Assigned category 



NQC 



KI 



NI 



9 

 69% 



1 



14% 



5 

 39% 



5 

 39% 



6 



38% 



4 

 31% 



5 

 71% 



3 

 23% 



4 

 25% 



3 

 23% 



2 



15% 



UP 



2 



15% 



5 



39% 



1 



6%' 



PI 



1 



8% 



5 

 31% 



Table 5 



Cross validation results of a three-category discriminant 

 function classification for adult Pacific halibut in the 

 northeast Pacific based on parasite data. Numbers offish 

 assigned to a category and the corresponding percentage 

 of the sample in that category are shown. Correct clas- 

 sifications are shown in bold (83% of 240). OR-SQC = 

 Oregon-northern California to southern Queen Charlotte 

 Islands, NQC-SB = southeast Alaska to southern Bering 

 Sea, PI-SMI = Pribilof Islands to St. Matthew Island. 



Assigned category 



True category 



OR-SQC 



NQC-SB PI-SMI 



OR-SQC 

 NQC-SB 

 PI-SMI 



63 



83% 



10 



7% 



7 

 9% 



112 



84% 



5 

 17% 



12 



9% 



25 



83% 



Table 7 



Cross validation results of a three-category discriminant 

 function classification for juvenile Pacific halibut in the 

 northeast Pacific based on parasite data. Numbers of fish 

 assigned to a category and the corresponding percentage 

 of the sample in that category are shown. Correct classi- 

 fications are shown in bold (66% of 62). NQC = northern 

 Queen Charlotte Islands, NI = Nagai Island, UP = Unimak 

 Pass, PI = Nunivak Island (central Bering Sea). 



True category 



NQC-NI 



UP 



PI 



Assigned category 



NQC-NI 



UP 



PI 



30 

 91% 



6 



46% 



10 

 63% 



6 

 46% 



1 

 6% 



1 



8% 



5 

 31% 



not lose their southern character. Winter sampling could 

 potentially determine if this is the case. 



With respect to the Bering Sea, we suggest that the 

 majority of the mixing occurs in the southern Bering Sea 

 because classification breaks down when the southern 

 Bering Sea is included in the northern region. This mix- 

 ing is consistent with larval studies that show that larvae 

 enter the Bering Sea through the Aleutian chain. Those 



fish may not disperse far into the Bering Sea. Rather, they 

 either remain in the southern Bering Sea or migrate back 

 to the Gulf of Alaska area (Skud [1977] believed that both 

 occurred). A migration may explain why fish tagged in the 

 Bering Sea tend to be recovered at greater distances from 

 the tagging site than those tagged elsewhere (Geernaert, 

 1996). Migrations of the central and northern Bering Sea 

 group appear to be in a more northerly direction (Skud, 



