**The
title, authors, and abstract for this completion report are provided
below. For a copy of the completion report, please contact the GLFC via e-mail or via telephone
at 734-662-3209**
Genetic Stock Structure of Lake
Whitefish in Northern Lake Michigan
and Green Bay
Brian L. Sloss1, Justin A. VanDeHey2, Trent M. Sutton3,
Paul J. Peeters4, and
Philip J. Schneeberger5
1 U.S.G.S, Wisconsin Cooperative Fishery
Research Unit, College
of Natural
Resources, University of
Wisconsin-Stevens Point, Stevens Point,
WI 54481
2 Wisconsin Cooperative Fishery Research Unit, College
of Natural Resources,
University
of Wisconsin-Stevens Point, Stevens Point, WI
54481
3 University
of Alaska Fairbanks,
School of Fisheries and Ocean Sciences
245 O’Neill Building, Fairbanks, AK 99775
4 Wisconsin Department
of Natural Resources, 110 South Neenah,
Sturgeon
Bay,
WI 54235
5 Michigan Department of Natural Resources, 484 Cherry Creek Road,
Marquette,
MI 49855
Abstract
Lake whitefish (Coregonus clupeaformis) have comprised an important commercial fishery on Lake Michigan since the early 1800s. Concerns exist
regarding the commercial harvest of potentially shared stocks by Michigan and Wisconsin
state licensed and Tribal commercial fishing operations. Previous studies
indicated potential stock structure, however,
questions still exist regarding the number, identity, distribution, and
discreteness of lake whitefish stocks in Lake Michigan.
The objectives of the study were to determine if lake whitefish microsatellite and mitochondrial DNA genetic diversity was
sufficient to discriminate among spawning stocks of lake whitefish and if the
genetic population structure of spawning lake whitefish aggregates in northern
Lake Michigan and Green Bay could be delineated in terms of genetic stock
identification and degree of stock isolation. Distinct spawning aggregates were
assumed to represent potential stocks and differences at molecular markers were
assumed to describe population differentiation. Twelve resolved microsatellite DNA loci exhibited adequate levels of
diversity for population differentiation in terms of their allelic richness and
heterozygosity, met Hardy-Weinberg equilibrium expectations
and were subsequently considered useful for population differentiation. Two
mitochondrial DNA gene regions (D-loop and ND5) exhibited low sequence
diversity (π = 0.0002 and 0.0025, respectively) and low numbers of haplotypes (7 and 5, respectively). The observed diversity
did not meet a priori levels of genetic diversity deemed necessary for population
differentiation and mtDNA data was not further
pursued. Genetic stock identification using the 12 microsatellite
loci resolved between 5 and 7 potential genetic stocks. The resolved stocks corresponded
to geographically proximate populations clustering into genetic groups.
Analysis of molecular variance (AMOVA) suggested six genetic stocks present in
the lake. Within stock analyses (pairwise Fst) suggested all but one stock delineated by AMOVA was a
stable grouping (i.e., no between population differences) with the exception
being a Hog Island
and Traverse Bay grouping (NOE stock). This putative
stock showed significant differences between the two populations indicating
gene flow between a Naubinway-Epoufette stock (NOR
stock) and Hog Island
but not between NOR and Traverse
Bay. Elk Rapids was the
most genetically divergent population and actually masked the isolation by
distance that exists between all other populations within Lake
Michigan. Genetic mixture
analysis showed mixed stock analysis using the resolved stocks and molecular
markers can be accomplished with high accuracy. The coupling of genetic data
from this study with current demographic data and a comprehensive mixed-stock
analysis could allow for more efficient and effective management of this
economically and socially important resource.