McClelland and Melendy: Heminths as tags In delineating stock of Hippoglossoides plotessoides 



183 



western 4T division. Abun- 

 dances of C. strumosum 

 {F=9.58), the digenean Fel- 

 lodistomum sp. (F=11.61), 

 and the larval anisakine 

 nematode Pseudoterranova 

 decipiens (F=8.89), and 

 prevalence of the larval 

 digenean Stephanostomum 

 baccatum (F=8.64) were sig- 

 nificant factors in the clas- 

 sification of 4Vn plaice from 

 Smokey Channel and Lou- 

 isbourg Hole (A:=0.40), and 

 cross-validation resulted in 

 an overall classification ef- 

 ficiency of 70% (Table 4). 



Stepwise DFA of helminth 

 infections in plaice from all 

 four sampling locations in- 

 dicated abundances of E. 

 gadi (F=35.80), C. stru- 

 mosum (F=13.89), Fellodis- 

 toinum sp., (F=5.81), and P. 

 decipiens (F=4.75) and the 

 prevalence of iS. baccatum 

 (F=5.71) were significant 

 markers {K=0.30) for the 

 classification of plaice from 

 the entire (4T-4Vn) survey 

 area. The overall rate of cor- 

 rect classification, however, 

 was only 48%, and 51% of 

 the plaice from western 4T 

 divison were misclassified as 

 4Vn fish (Table 5). In a fi- 

 nal analysis of samples from 

 the east and west coasts of 

 Cape Breton Island (east- 

 ern 4T and Smokey Chan- 

 nel, respectively), E. gadi 

 abundance was again the 

 most important marker se- 

 lected (F=59.10), although 

 abundances of the larval 

 anisakine nematodes Ani- 

 sakis simplex (F=6.50) and 

 Contracaecum osculatum 

 (F=6.60) also contributed 

 significantly to classifica- 

 tion (A:=0.49). Cross-vali- 

 dation yielded a 77% rate 

 of overall correct classifica- 

 tion, but, although nearly all 

 Smokey Channel plaice were 

 classified correctly, more 

 than half of the plaice from 

 eastern 4T were misclassi- 

 fied as Smokey Channel fish 

 (Table 6). 



