• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Prestocking assessment of the prevalence and intensity of Diphyllobothrium ditremum (Creplin) plerocercoids in freshwater barriered lakes in Alaska

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Weiland_K_1989.pdf
    Size:
    57.88Mb
    Format:
    PDF
    Download
    Author
    Weiland, Keith Alan
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/7438
    Abstract
    Plerocercoids of the pseudophyllidean cestode Diphyllobothrium ditremum (Creplin, 1825) have significantly affected the success of using certain barriered lakes for the rearing, overwintering and smolting of juvenile coho (Oncorhynchus kisutch) and Chinook (Oncorhynchus tshawytscha) salmon by causing mass mortalities of these host fishes. The prevalence of cestode procercoids in copepods, the first intermediate host, was propose as a method for assessing the potential for cestode caused losses of salmon prior to stocking a lake. However, no procercoids were found in a total of 15,276 Diaptomus and 435 Cyclops spp. from three lakes on south Baranof Island examined for procercoids. Diaptomus kenai is suggested as the first intermediate host for Diphyllobothrium ditremum. despite the absence of procercoids in any specimens examined. Diaptomus kenai was the predominant copepod in the three lakes studied, and was the prey item occurring most frequently (percent occurrence, 73.7%) in the stomach contents of 95 resident coho. Coho, Chinook, and rainbow trout (Salmo gairdneri) were obvious second intermediate hosts of D. ditremum. Among three species of piscivorous birds examined from the lake sites, a single common merganser (Merqus merganser) contained seven mature worms resembling D. ditremum. A bioassay study using coho salmon fingerlings in net pens suspended within a "cestode infested" lake proved successful as an assessment method. Plerocercoids of D. ditremum were observed in 91% of the planted coho within twenty days of exposure in Osprey Lake. Coho mortalities of 46.2% and 22.4% were observed in two pens. Mean plerocercoid intensities for apparently normal, moribund, and dead coho were 11, 28, and 32 respectively. Moribund and dead coho each had significantly larger worm loads than apparently normal coho. Primary lesions observed from gross and histopathological examinations of parasitized coho from Elfendahl and Osprey lakes included: ascites with marked distension of the abdomen; hemorrhaging of viscera primarily adipose tissue and liver; and focal necrosis of organs from migrating plerocercoids.
    Description
    Thesis (M.S.) University of Alaska Fairbanks, 1989
    Date
    1989-05
    Type
    Thesis
    Collections
    Older Theses Not Clearly Affiliated with a Current College
    Theses (Unassigned)

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2022 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.