188 



Fishery Bulletin 101(1) 



ish Cap and the Labrador Sea according to their parasite 

 fauna (Templeman and Squires, 1960; Bourgeois and Ni, 

 1984). All areas sampled in our study are currently man- 

 aged as separate stocks, and our results do not suggest 

 that management strategies should change. However, the 

 inclusion of Cabot Strait in unit 1 in the winter should be 

 re-evaluated with further sampling. 



Our parasite results are in contrast with results us- 

 ing microsatellite DNA markers (Roques et al., 2002), in 

 which S. mentella from the Gulf of St. Lawrence could not 

 be differentiated from those of the Laurentian Channel. 

 For this species, only three divergent populations were 

 defined across the North Atlantic: 1) a western population 

 in the Gulf of St. Lawrence and offshore Newfoundland; 

 2) a panoceanic population; and 3) an eastern population 

 in Norway and the Barents Sea. Thus redfish from unit 1 

 could not be differentiated from those of unit 2. Similar re- 

 sults were reported for S. fasciatus sampled in units 1 and 

 2 (Roques et al., 2001). Redfish populations in both units 

 are characterized by the presence of hybrid and intro- 

 gressed individuals between S. fasciatus and S. mentella 

 (Roques et al., 2001). Stock distinction does not preclude 

 genetic exchange between stocks, but managers must be 

 aware of the size and spatial boundaries of stocks, as well 

 as the level of gene flow between the stocks. 



Acknowledgments 



We thank Johanne Guerin. Helene Dionne, and Yves Des- 

 devises for technical assistance in the laboratory. The map 

 was prepared by Eric Parent. Lastly, we appreciate the 

 assistance of the officers and crew of the research vessels 

 C.S.S. Alfred Needier, C.S.S. Teleost, and C.S.S. Wilfred 

 Templeman for assistance with the sampling. 



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