Understanding Genetically-Distinct Lake Trout Populations in Mistassini Lake, QC

Maintaining population diversity is critical for species survival. Recent research has documented multiple genetically- and morphologically-distinct fish populations in many large, north temperate lakes. Little is known about lake trout (Salvelinus namaycush) in Mistassini Lake, QC. We aimed to characterize the population structure by using morphological/genetic tools and local Cree traditional knowledge (TK). Our research objectives included 1) determining the genetic population structure; 2) identifying the spatial structure of these populations in relation to habitat and depth; 3) evaluating the relationship between genetic and morphological data; and 4) compiling and integrating Cree TK, which will address potential changes in the number and size of lake trout captured over the last four decades. Using nineteen microsatellites from 636 tissue samples we demarcated the number of populations. Landmark-based morphometric data in combination with DNA was used to assess whether a correspondence exists between morphological and genetic data in demarcating populations. TK was compiled from local experts via interviews and personal interactions. Results indicate that Mistassini Lake is home to a minimum of five genetically-distinct populations related to habitat niches at varying depths. This research will provide vital baseline information on lake trout diversity, which has implications for management, conservation and restoration.