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Subject: ASSISTANTSHIPS
From: Al Zale <[log in to unmask]>
Reply-To:Academic forum on fisheries ecology and related topics <[log in to unmask]>
Date:Tue, 6 May 1997 17:19:52 +0200
Content-Type:text/plain
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GRADUATE RESEARCH ASSISTANTSHIPS
WHIRLING DISEASE INVESTIGATIONS
MONTANA STATE UNIVERSITY, BOZEMAN

Four (4) graduate research assistantships are available immediately at
Montana State University for studies concerning salmonid whirling
disease.  Applications for both MS and PhD degree programs are being
accepted.  Minimum Qualifications:  GPA >3.0, verbal + quantitative
GRE >1100; BS in fisheries or related field for MS assistantships, MS
in fisheries or related field for PhD assistantships.

1.  Relation of Life History Type to Whirling Disease Susceptibility in
Missouri River Rainbow Trout.

This project will examine life-history types of rainbow trout in the blue-
ribbon section of the Missouri River near Helena, Montana, where
recent sampling has confirmed the presence of whirling disease.
Distribution studies of the oligochaete Tubifex tubifex, the other
known host of the whirling disease-causing parasite Myxobolus
cerebralis, indicate that tubifex are rare in some spawning tributaries.
Thus, life history types that spawn and rear in these tributaries for at
least the first summer prior to migration to the mainstem may be at
reduced risk to the disease.  Objectives of the study are:  determine
timing and location of spawning using spawning weirs and redd
surveys; determine contribution of various fry life history types to
averall adult recruitment in the mainstem; test methods for
determining life history type using scales and otoliths; determine fry
production changes as whirling disease spreads through the system;
and identify possible rainbow trout life-history types that could be
used to bypass effects of whirling disease in other river systems.  An
overall goal of the study is to test the utility of various techniques
(batch marking of outmigrant fry, scale and otolith banding patterns,
otolith microchemistry) for determining life history type in wild
salmonids.

PhD student preferred.  Experience in ageing scales and otoliths, fish
trapping, and strong chemistry background desirable.  To apply, send
letter of interest, resume, transcripts, GRE scores, and names of three
references to Thomas McMahon, Fish and Wildlife Program,
Department of Biology, Montana State University, Bozeman, MT
59717.  Email: [log in to unmask] (no telephone calls
please).

2.  The Role of Tubificid Worms in Salmonid Whirling Disease.

Whirling disease is a parasitic disorder that can be fatal to salmonid
fishes.  The parasite that causes the disease, Myxobolus cerebralis
(Myxozoa: Myxosporea), has has been implicated in severe declines of
wild rainbow trout (Oncorhynchus mykiss) populations in Montana and
Colorado.  The life cycle of M. cerebralis alternates between a
salmonid fish an an aquatic worm.  Tubifex tubifex (Oligochaeta:
Tubificidae) is known to be one host.  Whether other worms can be
hosts is unclear.  It is the purpose of this study to investigate, using
controlled, laboratory experiments, the effect of environmental
conditions on the ecology of infection of T. tubifex and other species
of tubificids by M. cerebralis.  Specifically, worm infection levels,
release of particles that cause infection in fish, and life cycles of
infected and uninfected worms under two different temperature
regimes, will be compared among worm species and variants of T.
tubifex.  This work will begin to elucidate the role of tubificids in
whirling disease and aid in our understanding of why whirling disease
seems to be a problem in some areas and not in others.

MS student preferred.  Experience in invertebrate and worm culture
and identification and laboratory histological techniques desirable.  To
apply, send letter of interest, resume, transcripts, GRE scores, and
names of three references to Billie Kerans, Fish and Wildlife Program,
Department of Biology, Montana State University, Bozeman, MT
59717.  Email: [log in to unmask] (no telephone calls
please).

3.  Restoration of Wild Rainbow and Cutthroat Trout to the Upper
Madison River in the Face of Whirling Disease.

This project is part of a multipronged effort to restore wild trout to
their former abundances in the upper Madison River.  Wild rainbow
trout have declined 90% due to the effects of whirling disease over
the past 5 years in this section of one of the most productive  and
popular wild trout fisheries in the U.S.  One possibility for maintaining
wild trout populations is via maintenance/introduction of life history
types with specific behavioral characteristics that reduce exposure to
whirling disease infection during the highly vulnerable young fry stage.
Phase One of this restoration effort will be to identify tributaries that
have low incidences of whirling disease infection and that have
suitable spawning and rearing habitat for possible reestablishment of
wild rainbow or cutthroat trout.  This project will involve habitat
surveying of potential spawning and rearing tributaries and
radiotracking to determine current spawning locations and life histories
of surviving rainbow and cutthroat trout in the upper Madison River.

MS student preferred.  Experience in habitat surveying and/or
radiotelemetry desirable.  To apply, send letter of interest, resume,
transcripts, GRE scores, and names of three references to Thomas
McMahon, Fish and Wildlife Program, Department of Biology, Montana
State University, Bozeman, MT 59717.  Email:
[log in to unmask] (no telephone calls please).

4.  Effects of Age, Dose, and Environmental Stress on Development of
Whirling Disease in Rainbow Trout.

The development and severity of pathology of whirling disease in
salmonids is known to be dependent generally on the age of fish when
exposed to the infective triactinomyxon stage of  Myxobolus
cerebralis, and on the density of triactinomyxons to which the fish are
exposed.  Nevertheless, no systematic determination of the effects of
these factors, and their interaction, has been conducted.  Accordingly,
fishery managers remain unsure of the ages at which young trout may
become resistant to development of whirling disease, especially when
exposed to different parasite doses.  This uncertainty precludes
effective management of wild trout fisheries, including managing for
life history types that spawn and rear in  M. cerebralis-free habitats,
but that later migrate to infected waters.  To remedy these information
deficiencies, comparative testing of disease susceptibility of different
ages of rainbow trout Oncorhynchus mykiss exposed to different
parasite doses will be conducted in a replicated factorial experiment
under standardized laboratory conditions (in MSU's new Wild Trout
Research Laboratory).  Complementary assessments of the effects of
stress on the development of whirling disease and infection on stamina
will also be performed.  Other aspects of susceptibility will be
examined in subsequent segments of the project.  By gaining a better
understanding of this parasite and the disease it manifests,
management activities can be designed to enhance viability and
productivity of wild trout populations in M. cerebralis-positive river
systems.  This is a laboratory study.  It will be conducted in
collaboration with Elizabeth MacConnell, Fish Pathologist, Bozeman
Fish Technology Center, U.S. Fish & Wildlife Service.

PhD student preferred.  Experience in fish diseases and laboratory
maintenance of experimental aquatic organisms desirable.  To apply,
send letter of interest, resume, transcripts, GRE scores, and names of
three references to Al Zale, Montana Cooperative Fishery Research
Unit, Department of Biology, Montana State University, Bozeman, MT
59717.  Email: [log in to unmask] (no telephone calls
please).

For information on the MSU Biology Department and graduate
program, visit our website at www.montana.edu/wwwbi/

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