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<br />
<br />Comparison of suitability curves for coldwater and
<br />warmwater fishes reveals that, generally, warm-
<br />water stream biota are characteristically habitat
<br />generalists, able to occupy a wider range of depth,
<br />velocity, and substrate conditions than coldwater
<br />biota. Consequently, an analysis using the Physical
<br />Habitat Simulation (PHABSIM) system of the IF 1M
<br />generates habitat-discharge relations that are broad
<br />and flat (without sharp inflection points) for warm-
<br />water stream ecosytems. Such habitat-discharge
<br />relations are difficult to use in an assessment or
<br />management context. A similar analysis performed
<br />on a coldwater stream ecosystem generally produces
<br />more definitive results.
<br />In summary, the basic assumption that stream
<br />flow is an important factor determining habitat
<br />quality for warmwater fishes is probably valid, al-
<br />though the precise manner in which river flow is
<br />related to habitat (or biomass) has not been de-
<br />scribed to the level of detail required for assessment
<br />of impact. Consequently, application of the IFIM to
<br />assess effects of river regulation or water with-
<br />drawal on warm water fishes cannot be performed
<br />at a level of defensibility equivalent to that of cold-
<br />water stream applications until the unique hydrol-
<br />ogy and biology of these systems are described in
<br />greater detail and these findings incorporated into
<br />the IFIM.
<br />
<br />Information Sources
<br />
<br />Bovee, K. D. 1982. A guide to stream habitat analysis
<br />
<br />ApPLYING IFIM TO WARMWATER STREAMS 35
<br />
<br />using the Instream Flow Incremental Methodology. U.S.
<br />Fish WildI. Serv., FWS/OBS-82/26. 248 pp.
<br />Bovee, K. D. 1986. Development and evaluation of habitat
<br />suitability criteria for use in the Instream Flow In-
<br />cremental Methodology. U.S. Fish WildI. Serv.,
<br />FWS/OBS-8617. 235 pp.
<br />Gore, J. A., and J. M. Nestler. 1988. Instream flow studies
<br />in perspective. Regulated Rivers 2:93-101.
<br />Mathur, D. L., W. H. Bason, E. J. Purdy, Jr., and C. A.
<br />Silver. 1984. A critique of the Instream Flow In-
<br />cremental Methodology. Can. J. Fish. Aquat. Sci.
<br />42:825-831.
<br />Milhous, R. T., D. L. Wegner, and T. J. Waddle. 1981.
<br />User's guide to the Physical Habitat Simulation System.
<br />U.S. Fish WildI. Serv., FWS/OBS-81143. 254 pp.
<br />Larimore, R. W., and D. D. Garrels. 1985. Assessing
<br />habitats used by warm water stream fishes. Fisheries
<br />10(2):10-16.
<br />Nestler, J. M., R. T. Milhous, and J. B. Layzer. 1989. In-
<br />stream habitat modeling techniques. Pages 295-315 in
<br />G. E. Petts and J. A. Gore, eds. Alternatives in regulated
<br />river management. CRC Press, Inc., Boca Raton, Fla.
<br />344 pp.
<br />Nestler, J. M., R. T. Milhous, J. Troxel, and J. A.
<br />Fritschen. 1986. Effects of flow alterations on trout,
<br />angling, and recreation in the Chattahoochee River,
<br />between Buford Dam and Peachtree Creek. Tech. Rep.
<br />E-86-10, U.S. Army Corps of Engineers, Waterways
<br />Experiment Station, Vicksburg, Miss. 105 pp.
<br />Orsborn, J. F., and C. H. Allman, editors. 1976. Instream
<br />flow needs, V ols. I and II. American Fisheries Society,
<br />Bethesda, Md. 551 pp. and 657 pp.
<br />Orth, D. J. 1987. Ecological considerations in the develop-
<br />ment and application of instream flow-habitat models.
<br />Regulated Rivers 1:171-181.
<br />Orth, D. J., and O. E. Maughan. 1982. Evaluation of
<br />the Incremental Methodology for recommending
<br />instream flows for fishes. Trans. American Fisheries
<br />Society 111:413-445.
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