AQUATIC GAP

Surveys to Evaluate Fish Distribution Models for the Upper Missouri River Basin Aquatic GAP Project

Steve E. Freeling 1, Charles R. Berry, Jr. 2, Ryan M. Sylvester 1, Steven S. Wall 1, and Jonathan A. Jenks 1

1Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings

2U.S. Geological Survey, South Dakota Cooperative Fish and Wildlife Research Unit, South Dakota State University, Brookings

Introduction

For terrestrial vertebrates, the Gap Analysis Program has generated what Scott et al. (1993) called “the necessary ingredients for anticipation of endangerment of species with the ultimate goal of predicting areas of high biodiversity.” The necessary ingredients include maps of land cover, terrestrial vertebrate distributions, and land stewardship. With the aquatic component of Gap Analysis, analyses are done within watershed boundaries using valley segments as the finest resolution (Wall et al. 2004). We report here on surveys used to evaluate fish species distribution models for the aquatic GAP project of the huge Missouri River Basin.

The longest river in North America, the Missouri flows through the northern Great Plains for 3,768 km to its confluence with the Mississippi River. The river has been greatly altered in the past century for flood protection, navigation, irrigation, and power production. Twenty-five families, containing 136 species, compose its ichthyofauna. Populations of 24 species are known to be declining. Eleven fishes are listed as imperiled by two or more of the seven main-stem states (Galat et al. 2004). Plans for conserving these species and areas of high species diversity might be assisted by the Gap Analysis data provided by our project.

The Missouri River Gap Analysis Project is a partnership between South Dakota State University, working in the upper basin, the Missouri Resource Assessment Program, working in the lower basin, and the U.S. Geological Survey. Models are being developed to predict the distribution of fish species. Our purpose is to report on the initial fieldwork done in the upper basin to test the accuracy of the fish distribution models.

Site Selection

One watershed was selected from each U.S. state and one Canadian province in the upper Missouri River basin. We met with each state and provincial game and fish agency to inform them about the GAP program and select watersheds for sampling. We tended to choose watersheds that lacked fish community data and were the right size for our planned effort. The selected watersheds (Figure 1) were the Beaver River ( North Dakota), Elm River ( North Dakota and South Dakota), Frenchman River ( Saskatchewan and Montana), Nowood River ( Wyoming), and Sweetgrass River ( Montana).

Figure 1. Five watersheds sampled (black polygons) in the Upper Missouri River Basin (gray polygon).

Streams in each watershed were stratified into three stream types: headwaters, creeks, and small rivers, which were determined from the shreve order (Shreve 1967). Shreve orders were < 9 for headwaters, 10-75 for creeks, and 76-1500 for small rivers (Wall et al. 2004). Eight general sites were selected for each stream type in each watershed, with the goal of sampling six reaches in each of the three stream types. A reach was a stream segment approximately 39 times the mean stream width (Patton et al. 2000) (50 to 200 m) and included at least one riffle, pool, and run. Our goal of sampling 18 reaches was not met in three watersheds (Table 1) for a variety of reasons, including few tributaries to choose from, lack of access permission, and lack of flow.

Fish Sampling

Fish were collected with a battery-powered electrofisher (Smith-Root model LR-24) and a bag seine (9.1 m x 1.2 m with 5-mm delta mesh). The electrofisher was inefficient in wide streams, in deep pools, or in turbid water, thus seining was also used. Sampling started at the downstream end of a reach and progressed upstream in a zigzag pattern; no block nets were used (Simonson and Lyons 1995). Fish were held in 11.4-L plastic pails before being identified to species, counted, and released at the downstream end of the reach. Seining was done after electrofishing was completed.

Ancillary studies were planned to augment the basic project to access GAP fish distribution models. Habitat measurements included water chemistry, channel morphology, and riparian vegetation. These data may be valuable in future fisheries studies. Macroinvertebrates were collected with 15 sweeps from a D-frame dip net and three sediment core samples. These data are some of the first collected in these watersheds. White sucker were collected to determine population metrics. White suckers were chosen because of their occurrence in all watersheds, thus leading to the possibility of analysis of growth over a large spatial scale.

Results

A total of 41 species were identified among the 19,556 fish collected in the five watersheds. Fathead minnow and white sucker were most abundant (50% of all fish sampled) and were found in all five watersheds (Table 2). The Beaver River watershed had the highest species richness (21 species) and contained six species not found elsewhere (i.e., emerald shiner, red shiner, white bass, spottail shiner, yellow perch, and gizzard shad). The first three species inhabit open channels of large, permanently flowing rivers with low gradient (Pflieger 1997). The high species richness and presence of unique species probably occurred because this was the only direct tributary to the Missouri River. Northern redbelly dace, a cool water species (Brown 1971), were recorded for the first time in ten years in the Beaver watershed. The Elm River contained 17 species and had the greatest number of fish per site (971). Three lentic predatory fish (bluegill, black crappie, and largemouth bass) were only found in the Elm watershed. The presence of these lentic species may be due to stocking in the numerous impoundments in the watershed and also may have localized effects on riverine species richness and abundance.

The Frenchman River watershed contained two unique species (plains minnow and pearl dace). This is the first documented occurrence of the plains minnow in Canada. The Nowood River and Sweetgrass River watersheds had very similar species assemblages with 11 of the same species, mainly trout and sucker species (Table 2); this is because both are cold-water, mountainous watersheds. Fish data and habitat measurements have been provided to the state or provincial agencies for use in their future management decisions and reports.

Future Plans

Fish habitat models are being developed using Chi-squared Automatic Interaction Detector (CHAID; SPSS 2001), which is a decision tree derived from algorithms. The Lower Missouri River Aquatic GAP project team is using similar methods. Accuracy will be assessed using data splitting, jackknifing, resubstitution, and an independent data set (Fielding and Bell 1997). Cohen’s Kappa will be used to assess chance corrected accuracy of the model (Titus et al. 1984). Macroinvertebrate assemblage will be used to determine if relationships exist between fish presence and macroinvertebrate presence (Lammert and Allan 1999). Macroinvertebrate assemblage may also be used in the discussion of commission and omission errors in the model.

In summary, the Missouri River Aquatic GAP Project is on schedule. The fieldwork has added information to fisheries databases managed by states and the province of Saskatchewan. Our experiences will be useful for Aquatic GAP projects that follow.

Literature Cited

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Galat, D., C. Berry, W. Gardner, J. Hendrickson, G. Mestl, G. Power, C. Stone, and M. Winston. 2004. Spatiotemporal patterns and changes in Missouri River fishes. In J. Rine, R. Hughes, and R. Calamusso, editors. Historical changes in fish assemblages of large American Rivers. American Fisheries Society Symposium.

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Pflieger, W.L. 1997. The Fishes of Missouri. Conservation Commission of the State of Missouri, Jefferson City, Missouri. 372 pp.

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Titus, K., J.A. Mosher, and B.K. Williams. 1984. Chance-corrected classification for use in discriminant analysis: Ecological applications. The American Midland Naturalist 111:1-7.

Wall, S.S., C.R. Berry, Jr., C.M. Blausey, J.A. Jenks, and C.J. Kopplin. 2004. Fish-habitat modeling for gap analysis to conserve the endangered Topeka shiner (Notropis topeka). Canadian Journal of Fisheries and Aquatic Sciences 61:954-973.