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<br />Mark and recapture formula (McNaughton and
<br />Wolf, 1973 [10811:
<br />
<br />M R
<br />N N,
<br />
<br />where N = total population
<br />M = number marked the first time
<br />N, = total number in the second
<br />sample
<br />R = number in the second sample
<br />that was marked at the
<br />first capture
<br />
<br />The mark and recapture method for estimating
<br />fish populations is based on randomness assump-
<br />tions which include equal ability to catch each
<br />individual and random movement of marked in-
<br />dividuals throughout the population. It must also
<br />be assumed that no fish have been added to or
<br />subtracted from the population between the
<br />time of marking and resampling.
<br />
<br />The keys used in the identification of aquatic
<br />animals are from the sources listed below:
<br />
<br />Eddy. S.. How to Know the Freshwater
<br />Fishes, Wm. C. Brown Co. Publishers,
<br />Dubuque, Iowa. 1957.
<br />Edmondson. W. T., editor, Fresh Water
<br />Biology, John Wiley and Sons, Inc., New
<br />York. 1959.
<br />Hilsenhoff. W. L.. Aquatic Insects of Wiscon-
<br />sin, Department of Natural Resources,
<br />Madison. Wise.. 1975.
<br />Hiltunen. J. K., A Laboratory Guide-Keys
<br />to the TubiflCid and Naiad Oligochaeta of
<br />the Great Lakes Region, unpublished,
<br />1973.
<br />Mason, W. T., An Introduction to the Identifi.
<br />cation of Chironomid Larvae, U.S. Govern-
<br />ment Printin9 Office. Washington. D.C.,
<br />1973.
<br />Needham, J. G. and P. R. Needham, A Guide
<br />to the Study of Freshwater Biology, 5th ed.
<br />Holden-Day, Inc., San Francisco. Calif.,
<br />1962.
<br />Pennak. R. W., Freshwater Invertebrates of
<br />the United States, 2nd ed., John Wiley and
<br />Sons, Inc.. New York. N.Y., 1978.
<br />Parrish. F. K., Keys to Water Quality Indi-
<br />cative Organisms {Southeastern United
<br />Statesl, U.S. Government Printing Office,
<br />Washington, D.C., 1968.
<br />
<br />Usinger, R.L., editor, Aquatic Insects of Cali-
<br />fornia, University of California Press.
<br />Berkeley, Calif., 1956.
<br />
<br />RESULTS
<br />
<br />Temperature
<br />
<br />Temperatures in the river ranged from 0 to
<br />1 7.4 0 C throughout the study section during the
<br />year (table 1). Water temperature in the Lead-
<br />ville Drain remained fairly constant, ranging from
<br />6.9 to 7.5 oC. while California Gulch water had
<br />a wide range. from as low as 0.1 oC during the
<br />winter months to a high of 18.2 0 C during late
<br />summer.
<br />
<br />Dissolved Oxygen (D.O.)
<br />
<br />Concentrations of dissolved oxygen (table 11 at
<br />all river stations during the year was near 100
<br />percent of saturation. As the temperature in-
<br />creased, the dissolved oxygen content usually
<br />decreased.
<br />
<br />pH
<br />
<br />The river was slightly alkaline !table 1); how-
<br />ever, the pH in the Leadville Drain dropped to a
<br />low of 6.5 and in California Gulch dropped to
<br />3.3 during the early spring. The pH at all river
<br />stations was usually nearest neutral during the
<br />peak of the spring runoff.
<br />
<br />Conductivity
<br />
<br />Conductivity ranged from 60 to 460 !,S/cm at
<br />the various river stations during high and low
<br />flows, respectively (table 1 I. The Leadville Drain
<br />reached 1070 !,S/cm. and California Gulch had
<br />a maximum conductivity of 1520 !,S/cm, indi-
<br />cating high concentrations of dissolved sub-
<br />stances in both of these waters.
<br />
<br />Oxidation-Reduction Potential {Eh}
<br />
<br />The Eh values (table 11 indicated that all stations
<br />were in an oxidized state. except during the
<br />early spring, when slightly reducing conditions
<br />existed in California Gulch and at AR-3.
<br />
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