Missouri River Benthic Consortium 1998
Introduction and Project Background
Managing the Missouri River basin for a diversity of contemporary co-equal
needs (flood control, irrigation, water supply, navigation, hydropower, recreation, and
fish and wildlife) is a challenging responsibility. Modifications to the ecological
integrity of the natural Missouri River-floodplain ecosystem from impoundment and
reservoir operation, channelization and channel maintenance, flood control, and water
pollution have been immense and ongoing for over 150 years (Hesse et al. 1989, Schmulbach
et al. 1992, Galat et al. 1996). Implementation of general (Petts 1984, National Research
Council 1992, Berry and Galat 1993) and specific strategies (e.g., Hesse and Mestl 1993,
Hesse and Sheets 1993, Hesse, et al. 1993a, Galat et al. 1996) to restore some semblance
of a naturally functioning Missouri River-floodplain ecosystem necessitates knowledge of
habitat requirements and population dynamics of fish and wildlife resources within the
basin.
Native fishes have been identified as the group most jeopardized by past
and present management practices on the Missouri River (Hesse et al. 1993b, USFWS 1994a).
Over twenty species are currently listed as rare, threatened, or of special concern by
states or the federal government (Whitmore and Keenlyne 1990). While only one fish (pallid
sturgeon, Scaphirhynchus albus) is currently listed as federally endangered
an additional eight species (lake sturgeon*, Acipenser fulvescens;
blue sucker*, Cycleptus elongatus; western silvery minnow*,
Hybognathus argyritis; plains minnow*, H. placitus;
sturgeon chub*, Macrhybopsis gelida; sicklefin chub*,
M. meeki; flathead chub*, Platygobio gracilis; and
paddlefish, Polyodon spatula) are proposed or considered possibly
appropriate for listing by the USFWS (i.e., Category 1 or 2, USFWS 1994b). Most recently
sicklefin and sturgeon chubs have been petitioned to the USFWS for listing as endangered.
Examination of life histories of fishes at risk in the Missouri River (Pflieger 1975, Lee
et al. 1980) indicates that species characteristic of near-bottom or benthic habitats
(both in main- and off-channel) dominate the list (7 of 8 species, identified by *
above). Clearly, the highest priority research to yield baseline information and lead to
management alternatives to stabilize declining populations of these species and their
habitats should focus on the benthic community.
Research also suggests that population status of fishes at risk within the
Missouri River varies geographically. Healthiest populations of more species may persist
in the upper, little altered Missouri River and its major tributaries (Hesse et al. 1989,
White and Bramblett 1993). The section of greatest population decline is the middle and
lower Missouri River in areas of degraded channels downstream from main stem reservoirs
(Hesse and Mestl 1993, Hesse 1996). The lower channelized Missouri River in Missouri may
be somewhat intermediate as Pflieger and Grace (1987) found stable populations of several
species which Hesse (1996) reported as declining in Nebraska. What factors are responsible
for these apparent longitudinal differences are not immediately apparent. However,
possible differences in population dynamics of benthic fishes and habitat availability
along the Missouri River continuum offer an ideal opportunity to elucidate causal factors
and provide recommendations for alleviation. Factors associated with healthy populations
of fishes in one section of the river may provide the best model for conservation in other
sections. Addressing causes of decline and implementing restoration goals must therefore
incorporate an ecosystem perspective, encompassing the entire 2,341 miles of Missouri
River. The system-wide cooperative effort undertaken by this project will serve as a
baseline against which to evaluate future changes in Missouri River operating criteria.
Research is conducted by six USGS Cooperative Research Units in states along the Missouri River
(Montana,
Idaho,
South
Dakota, Iowa,
Kansas,
Missouri),
Montana Fish Wildlife & Parks
and CERC, Columbia, MO.
Our research goal is to evaluate population structure and habitat use of
benthic fishes along the entire main stem Missouri River, exclusive of reservoirs. Our
strategy of a basin-wide analysis of benthic fishes organized within a spatial habitat
hierarchy offers a high probability to predict how potential changes in system operation
can benefit conservation and recovery of fishes and their habitats while maintaining the
diversity of present-day public uses within the Missouri River basin.
Study Objectives
-
Describe and evaluate recruitment,
growth, size structure, body condition, and relative abundance of selected benthic fishes
-
Measure physical habitat features (e.g.,
velocity, bottom type, turbidity, temperature) where fishes are collected, and
-
Describe use of dominant macrohabitats
by benthic fishes.
Accomplishing these objectives requires that information be collected in a
standardized manner using identical techniques throughout the basin. Data must also be
recorded, analyzed and managed following standard protocols for it be useful to resource
agencies and decision makers. Well defined quality assurance and quality control
procedures are necessary to meet these needs. The purpose of the Standard Operating
Procedures (SOPs) described in this document are to provide this information.
A hierarchical habitat classification framework (Frissell et al. 1986,
Bain 1992, Hawkins et al. 1993) has been selected to stratify habitats and define where
fishes are sampled. The highest level or organization is the section based on
fundamental geo-political boundaries within the Missouri River Basin (e.g. free flowing,
channelized, state boundaries). Each section is divided into segments based on
geomorphic and constructed features (e.g., major tributaries, dams). Macrohabitats
are areas of distinctive, repeatable physical areas within segments defined based on
literature (e.g., Kallemeyn and Novotny 1977, Schmulbach et al., 1981, Cobb et al., 1989,
Latka 1994, Wilcox 1993, Hesse 1996) and field evaluations. Each macrohabitat is present
in all river segments and includes natural (e.g., sand island, tributary confluence) and
man-made (e.g., dike field, revetment) classes. By sampling representative macrohabitats
within each segment we should account for the diversity of conditions present. Specifics
of the aquatic macrohabitat classification used are described in Section 2.
Physical parameters are collected in conjunction with all fish sampling to
characterize habitats where fish are collected within macrohabitats and among study
segments and sections. These include: depth, velocity, substrate type, bed form, air and
water temperature, turbidity, conductivity, location, river stage and weather and are
described in Section 5. Site Specific Characteristics..
Fish Collection
Eighty-nine fish species have been recorded from the free-flowing Missouri
River (Ebasco Environmental 1992) and all may be captured by our gears. However, resource
limitations dictate we target a subset of 26 benthic taxa for evaluation of population
structure. This group includes all benthic fishes listed "at risk" by Missouri
River states and the USFWS as well as important commercial and recreational taxa (See SOP
4.1, Table 1). Criteria for inclusion as target species are: 1) primarily benthic habitat
use, 2) important as native (particularly "at risk"), commercial, recreational
or prey, and 3) presence in five of seven river sections.
Our approach to collect fishes has been to select the fewest gears
possible that effectively sample the greatest diversity of benthic fish species in the
widest variety of benthic habitats. Fish sampling will be conducted using a stratified
random sampling approach (Gutreuter 1993). One passive and 4 active gears are used:
stationary gill nests, bag seines, benthic trawl, boat electrofishing and drifting trammel
nets. A minimum of two gears are deployed in each macrohabitat sampled. Standard Operating
Procedures for deployment for each gear are described in Section 3. Fish Collection and
Gear Deployment. All fish captured by all gears will be identified and enumerated. Lengths
and weights for the 26 benthic species will be recorded from all individuals captured by
all gears and from all macrohabitats and segments. Common techniques are used for
estimating recruitment to gear (i.e., catch per unit effort or length frequency analysis),
relative abundance, condition (ponderal indices), and size structure among study segments
and sections. Growth data is collected from a subset of 12 of the 26 benthic fishes (SOP
4.1, Table 1) and analyzed at the Iowa and Kansas Units, see Section 4. Fish
Identification and Measurement, for SOPs.
Sampling Schedule
Fish sampling and measurement of physical habitat parameters are conducted
in summer and early fall (e.g., mid July - early October) based on ecologically meaningful
bounds (e.g., water temperature). This season was selected because the majority of
young-of-year fishes have recruited to our gears; flows are generally low, so all
macrohabitats are likely present, and; a short duration sampling schedule should reduce
within season temporal variability with respect to fish and macrohabitat measurements.
Project Support
Funding for this research is provided primarily by the U. S. Army Corps of
Engineers, Missouri River Division, Omaha and Kansas City Districts through a Memorandum
of Agreement with the USGS, Biological Resources Division. Other federal agencies
continued financial support include: Environmental Protection Agency Regions 7 and 8,
National Park Service, U. S. Bureau of Reclamation, USGS -Biological Resources Division,
and the U.S. Fish and Wildlife Service. Funding from the following state agencies has also
enabled Units to complete field work: Iowa Department of Natural Resources, Kansas
Department of Wildlife and Parks, Missouri Department of Conservation, and the North
Dakota Game and Fish Department. State Fish and Wildlife Agencies from Montana, North
Dakota, South Dakota, Iowa, Kansas, and Missouri have all assisted Units with equipment
and supplies. The Missouri River Natural Resources Committee provides external review of
research objectives and progress, and has assisted in securing funding for this research.