Application of Microsatellite and Mhc Markers to Stock Identification in Lake Superior Lake Trout
Ruth Phillips
The rehabilitation of lake trout in Lake Superior is one of the Great Lakes’ brightest success stories. Through the efforts of scientists and managers, the once-decimated populations of trout have rebounded significantly. As these populations continue to recover, it is important to determine the stock structure so the fish can be managed for a sustainable harvest.
Lean and siscowet lake trout are closely related salmonids in Lake Superior. Although distinct as adults, the young fish look the same. In order to monitor the trout fishery better, managers need a way to tell the two fish apart at all ages.
In this project, researchers are identifying genetic markers to aid in stock identification and to distinguish between young lean trout and young siscowet trout. This work is leading to the development of a noninvasive DNA test—important because fish will not have to be killed to obtain genetic samples.
State, federal, and tribal agencies involved with rehabilitation programs can use such technology to manage the recovering lake trout fishery in Lake Superior more efficiently.
Update - February 1999
Microsatellites have been shown to be very sensitive genetic markers for animal populations, including fishes. Preliminary data from the microsatellite analysis of 15 major spawning populations of lake trout from different locations around Lake Superior indicate that this technique will be useful in distinguishing lean lake trout from siscowets. The results also show that several genetically distinct subpopulations exist for both morphotypes. Lean lake trout from adjacent regions tend to be closely related, but siscowets do not always group by region. It seems that other factors, including depth, may be important in determining where siscowets of similar genetic origin can be found. A workshop on stock identification using molecular and morphological techniques is planned for July 1999 and will focus on salmonids native to Wisconsin.
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