Natural Hybridization between Arctic Char (Salvelinus alpinus) and Brook Trout (S. fontinalis): Evidence from Northern Labrador

Abstract

Electrophoretic analysis of successive samples of Salvelinus collected in the Fraser River watershed of northern Labrador in 1984 and 1986 revealed the existence of natural hybrids between Arctic char (Salvelinus alpinus) and brook trout (S. fontinalis). We examined 11 electrophoretic loci in liver tissue; 10 loci were informative and six were diagnostic of the two species and their hybrids. The electrophoretic phenotypes of some hybrid specimens sugested that they were second-generation hybrids and/or backcrosses to the parental species. Hybrids were represented by six different year classes, indicating that crossing between the species in the system is a regular occurrence. The hybrids, although visually difficult to distinguish from brook trout, were meristicaîly intermediate or more closely resembled Arctic char. The observations raise a number of questions regarding the ecological circumstances promoting hybridization in the evolution of Arctic char and brook trout populations. The results stress the need for restrictions on introducing brook trout into systems with original populations of Arctic char. Further, Arctic char from the Fraser River are commonly used for aquaculture research and development; therefore, there is a clear need to screen fish carefully to determine whether or not they represent introgressed gene pools.

Arctic charr (Salvelinus alpinus): a case study of the importance of understanding biodiversity and taxonomic issues in northern fishes

“…This is a relatively frequent occurrence in charrs (e.g. Hammar, Dempson, and Verspoor 1991;Wilson and Bernatchez 1998). The resulting genetic exchange over both evolutionary and contemporary time scales serves to increase diversity within lineages (e.g., introduction of novel genotypes) or to homogenise lineages if it occurs to a significant degree.…”

Low levels of hybridization between sympatricArctic char (Salvelinus alpinus) andDollyVarden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation

“…Although consistent morphological differences exist between Arctic char and Dolly Varden throughout this zone of sympatry (e.g., pyloric ceca, gill raker counts), McPhail (1961) identified populations that had ambiguous morphology and speculated that they resulted from hybridization between the species which is not uncommon in Salvelinus (e.g., Hammar et al. 1991; Taylor et al. 2001; Redenbach and Taylor 2003).…”

Evaluate the Life History of Native Salmonids in the Malheur Subbasin, Fiscal Year 2008 Annual Report.

“…Hybridization among members of the genus Salvelinus is not uncommon (Hammar et al 1991;Wilson and Hebert 1993;Baxter et al 1997). While the majority of hybrids documented among Salvelinus have been F1s, post-F1 hybrids have been produced for aquaculture (Anderson and Collins 1995) and observed in the wild (Baxter et al 1997).…”