Montana's Fish Species of Special Concern
Sicklefin Chub
Grant Grisak
Montana Cooperative Fisheries Research Unit
Montana State University
Bozeman, Montana 59717
June 1998
Status
The sicklefin chub (Macrhybopsis
meeki), is presently listed as a species of special concern, class B, by the
State of Montana (Hunter 1994). Despite
a petition to list the species as federally endangered in 1994, it is currently
listed as a Category 1 species, meaning that there are sufficient data available
to support a listing proposal (USFS 1994).
Following the proposal to list as endangered, Montana Fish Wildlife and
Parks (FWP) conducted a population survey in the Missouri River above Fort Peck
Reservoir (Grisak 1996) and continues to collect data on the population in the
lower Missouri and Yellowstone rivers (Liebelt 1996) in an effort to gain more
knowledge of the species.
Distribution
The first observation of sicklefin chub in Montana was in
1979 in the middle Missouri River upstream of Fort Peck Reservoir (Gould 1981
and Gardner and Berg 1982). Until this time they were unknown to exist in the
state most likely because of the lack of sampling effort in eastern Montana.
At present, the distribution of sicklefin chub in Montana includes the
middle Missouri River from Cow Island downstream to the headwaters of Fort Peck
Reservoir (Grisak 1996), the lower Missouri River from the mouth of Redwater
River to the Yellowstone River confluence (Liebelt 1996), and in the lower
Yellowstone River, from Intake Diversion Dam to the confluence with the Missouri
(Ruggles 1997). As of 1997, the
known range of sicklefin chub encompasses nearly 280 kilometers of river in the
Missouri and Yellowstone drainages (Figure
4).
Figure 4. Distribution of
sicklefin chub in Montana, 1990-1997.
Life History/Ecology
Population characteristics of this species are not well
known, but it generally does not reach high densities like other chub species.
In 1994 and 1995 Grisak (1996) reported capturing a total of 121 and 123
sicklefin chubs while sampling in the middle Missouri River for 3 months each
year. The species reaches a maximum age of 4 years and generally becomes
sexually mature at the age of 2. Spawning
occurs in main channel areas of large turbid rivers which they inhabit.
The spawning period is in the summer months and probably occurs over a
wide time span, similar to other big river species.
Young of the year sicklefin chub have never been collected and early life
history remains a mystery. Although
the species has been sampled from shallow water and rocky substrate, there seems
to be a general preference for deeper water and sandy substrate. Unlike the sturgeon chub, all of the Montana captures have
been from only the Missouri and Yellowstone rivers, indicating a strong
preference for large turbid rivers. Although
sympatric, there is no information that suggests this species hybridizes with
the other member of it's genus, the sturgeon chub (Macrhybopsis gelida).
Threats
The major threat to the sicklefin chub is thought to be
habitat alteration by dam operations and irrigation operations and development.
The pools created behind dams have innundated riverine habitats and
replaced the river with lake conditions, which is probably unsuitable habitat
for chubs. Dams also may create
unsuitable habitat for chubs in downstream waters by reducing turbidities and/or
altering temperature and flow regimes. Fortunately
it appears unlikely that any new dam will be built on the Yellowstone or
Missouri rivers in Montana in the foreseeable future. However, water regulation
at Fort Peck Dam and several other tributary dams continue to limit the
distribution and abundance of chub populations in Montana.
Irrigation projects are fairly numerous on the lower
Missouri, Yellowstone rivers and and there are potential problems that could
reduce sicklefin chub populations if proper safe guards are not provided.
Further reductions in stream flows associated with irrigation withdrawls
could degrade existing habitat for spawning and rearing.
Because little is known of sicklefin chub spawning
habitat requirements, consideration should be given to maintaining
suitable flows in areas like island side channels which are fundamental spawning
and rearing habitat for other big river species.
None of the irrigation withdrawl structures in the Missouri or
Yellowstone rivers are not screened and fish entrainment losses could be severe
under drought conditions or with additional irrigation systems.
Management
The management of this species should involve routine
monitoring (once every 2-3 years) of existing populations.
The program should be designed to monitor population trends, range
expansion or losses and collect additional information on life history and
ecology. This could be conducted
while sampling for other species. The
lack of proper monitoring of these populations could lead to their demise by
virtue of not recognizing if and when they are in jeopardy of becoming
extirpated by any artificial or natural entity.
Recommendations for operating reservoir and irrigation projects should be
developed for improving and maintaining sicklefin chub populations and habitats
in Montana.
References
Gardner,
W. M. and R. Berg. 1982. An analysis of the instream flow requirements for selected fishes in the wild and scenic portion of
the Missouri River. Montana Fish
Wildlife and Parks. Helena.
111pp.
Grisak, G.
G. 1996. The status and distribution of the sicklefin chub in the middle
Missouri River, Montana. Masters
thesis. Montana State University, Bozeman.
Gould,
W.R. 1981.
First records of the rainbow smelt (Osmeridae), sicklefin chub (Cyprinidae)
and white bass (Percichthyidae) from Montana.
Proc. Mont. Acad. Sci. 40:
9-10.
Hunter, C.
1994. Species of special
concern list, updated. Montana Outdoors. September/October.
Helena.
Liebelt,
J.E. 1996. Lower Missouri River and Yellowstone River pallid sturgeon study,
1994-1995. Montana Department of Fish, Wildlife and Parks. Helena.
Ruggles, M.P.
1997. Sections 2 & 3:
Upper Inter-Reservoir I and Lower Yellowstone River, Montana.
in D.J. Dieterman, M.P. Ruggles, M.L. Wildhaber, and D.L. Galat,
editors. Population structure and
habitat use of benthic fishes along the Missouri and Lower Yellowstone Rivers. 1997
Annual Report of Missouri River Benthic Fish Study PD-95-5832 to U.S. Army Corps of
Engineers and U.S. Bureau of Reclamation.
USFWS.
1994. 50 CFR 17 58996-59000. Endangered
and threatened wildlife and plants; animal candidate review. Federal Register
59;219. Washington, D.C.
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