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The Reproductive Cycle Of Lake Superior Siscowet Lake Trout

This project seeks to improve our understanding of the reproductive  biology of siscowet and lean lake trout in Lake Superior.  Specific  research objectives include; 1) determining the annual ovarian and  testicular maturational cycle of siscowet and lean lake trout in Lake  Superior east of the Keweenaw Peninsula, and 2) comparing the annual  ovarian and testicular maturational cycle of lean and siscowet lake  trout between populations east and west of the Keweenaw Peninsula.  Siscowet and lean lake trout will be sampled monthly (April-November)  by gillnet in Lake Superior east of Keweenaw Peninsula (Marquette,  MI), and at a site west of Keweenaw Peninsula in May, August, and  November.  During each sample, 15 adult females and 15 adult males   for each morphotype/sampling time will be analyzed for 1) metrics,  including total length, weight, age, gender, lamprey wounding and  digital phenotypes, 2) gonadosomatic index (gonad wt/body wt), 3)  gonadal histology, 4) circulating estradiol (female),  11-ketotestosterone (male), 17a, 2 ß-dihydroxy-4-pregnen-3-one  (postvitellogenic females) and vitellogenin (females) levels, and 5)  pituitary gonadotropin (GTH) mRNA levels.  Steroid hormone levels   will  be analyzed by established radioimmunoassays, pituitary GTH mRNA  levels by quantitative PCR and vitellogenin by commercial ELISA.  All  gonadal indices will be correlated with time of year between lean and  siscowets at sites east and west of the Keweenaw Peninsula. The  results of this study will help address the following questions: When  is gonadal maturation initiated and what is the progression to  spawning in siscowet and lean lake trout throughout the year?  How  consistent is the reproductive cycle from one year to another in the  same populations of siscowet and lean lake trout?  How similar is the  cycle between two different populations of siscowet and lean lake  trout? Knowledge of the biology of siscowet lake trout is relatively  limited compared to that of lean lake trout.  Information on siscowet  biology, especially reproductive biology, would be valuable in making  informed management decisions on the reintroduction of morphotypes  into Great Lakes that have lost their lake trout genetic and  morphotypic diversity.    

Status
In progress
Type
Project
Start Date
End Date
Researchers
Frederick GoetzPrincipal Investigator
Associated with 2 projects
Shawn SitarResearcher
Associated with 5 projects
Charles BronteResearcher
Associated with 2 projects
Penny SwansonResearcher
Associated with 1 projects
Agencies
Great Lakes Fishery Commission $ 76,663.00USDActual

Funding 54 projects for a total of $5,089,137.00
Scope of Study
Field Investigation
Laboratory Investigation
Scale of Phenomena
Biochemical
Cellular
Organism
Resource Management
Fisheries
Lake Basin Connecting Channels
Lake Superior
State Province
Michigan
Wisconsin
Annex Numbers
Research & Development
Surveillance and Monitoring
Annex 17
Physical and transformational processes affecting delivery of pollutants
General
Annex
  • Annex Numbers
    Annex Numbers
    Research & Development
    Surveillance and Monitoring
  • Annex 17
    Annex 17
    Physical and transformational processes affecting delivery of pollutants

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