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 ABSRC Xz~~~~~~~'h H U0:0 uef tasean becausethere was np commercialrfishery, With 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 ntire 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. R -.: ----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. -X-;:': - - - ^ ^ ; 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.