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Schram, Stephen T.; Margenau, Terry L.; Blust, William H. / Population biology and management of the walleye in western Lake Superior

Abstract PDF (727.6 KB)

Coerph  bGe     Po
 Xz~~~~~~~'h                H U0:0
                     uef                     tasean becausethere was np commercialrfishery,
                     we-t-; Lak Superior became morepaland st aciai     
     were re ivd
 -0  '^;,,g'.''  '<.,      nove  ent-,tF;  i p late n ,p op laio   d en
i y,  u vv l  iesa n d *h r tofti  tck  e ut
                     St.. louis River estuE  during spring spawningseason.Spawningost
  D~ ~ ~   ~    ~   ~~~Fn duLc Minsoa in-           a A--f- -n0 - d si2-mie
tre hofriver- beo  a owrdarppomtly2
                     --^-m-ileuriver fom LakeSup-erior. Near 5000 -matre-was
         nd aFdu
                     in 18and over 67,0001m   I       thehiver ande     comied.
-.: ----V-t---0:,0d f rate~ s ~w~ ereslowa ndinum er~ ousagecla ssewer epresentw
i ytha l s ut'g 0  a
                     - - -,- . - retur-ns indicated adult-walleyes  moedownstrea
f7'm  omthe rapaftersaw n  an
                     -Xremaininthe estuaryseveral wPeeks to several months
beforepen erig Lke p       c
                     in -   - ^ -      m-Lake Superior, the wlleyemoved eastward
during the summer but generally not past the
- -f --'-:-0 ;~ ;:-0 A postleIs lands;.Aw estw ardm owvem entb' acktotheS
uperiorE ntryoccurreddurinxg' latefall'
                     -0 0- or early winter. I'' '                  '    
                       ' Lymphocystis -was observed on walleyes handledduring
the 1980-85spawn ing p eriod.
 - '- 't- 0 - ~~~Annual survival was estimated at 58-60% 'for mature walleye.
                       -  -  -  ^ ^   ;  Sport angling increased- considerably
once-the fish became- edible. In addition, an assess-
                     ment commercial-fishery begane   in 1980 by the Red
Cliff Band ofChippewa. The two user
        -  -       - ~~~groups target separate segments-of the population.
Sport anglers harvest primarily immature
                     fish and m ales, and th e commercial fishery harvests
primarily mature fish, which average 60%
-               ~~~~~~~~~females. Management recommendations stress protecting
the size structure of the fishery and
    - '  '     \ ~~~~continued' data collection to monitor stock characteristics.
After the study was completed,
  -             ~~~~~~~~~more restrictive regulations went into effect both
on the St. Louis-River and in Lake Superior.
                  Key Words: Walleye,- sea lamprey, St. Louis River, Lake
Superior, Great Lakes, fisheries man-
              -  ~~agement, age structure, exploitation, movements, population
estimates, lymphocystis , harvest.

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