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4. Documentation of specific locations of fishery-related data collections to allow repeated site
<br />visits, which are essential to long-term monitoring.
<br />5. Visual representation of fishery resources and sample locations in the Colorado River in
<br />Grand Canyon to facilitate impact analyses and resource assessments.
<br />6. Facilitation of an exportation of data to other scientists and importation of newly collected
<br />information into a common data base.
<br />7. A consolidated fisheries data base for resource managers with the information necessary to
<br />assess impacts of Glen Canyon Dam operations on fisheries resources.
<br />Integrated Tabular Data Base
<br />Three principal types of fisheries data were identified, including historic accounts and
<br />collections, past surveys, and GCES investigations. Historic accounts include an assimilation
<br />of reports, photographs, and diaries of travelers and visitors through Grand Canyon (Kolb and
<br />Kolb, 1914), as well as some early fish collections (Miller, 1946; 1955). Past surveys include
<br />studies conducted before GCES was implemented in 1983 (McDonald and Dotson, 1960; Stone
<br />and Queenan, 1967; Stone and Rathban, 1968; Miller and Smith, 1973; Holden and Stalnaker,
<br />1975; Miller, 1946 and 1955; Minckley and Blinn, 1976; Sutkus, et al. 1976; Minckley, 1978;
<br />Carothers and Minckley, 1981; Kaeding and Zimmerman, 1983). Starting in 1983, GCES
<br />coordinated several past and ongoing studies (Maddux et al., 1987; Kubly, 1990; Angradi et al.,
<br />1992; Arizona Game and Fish Department, 1993 and 1994; Gorman, 1994; Otis, 1994; Allan,
<br />1993; Weiss, 1993; Valdez et al., 1982; Valdez and Hugentobler, 1993; Valdez and Ryel, 1995).
<br />Data from historic accounts and past surveys are assimilated from reports, identified by
<br />common format, and digitized in standard fields and codes to enhance archival value. Most data
<br />collected under GCES are digitized, and are available with permission and agreements with
<br />cooperating agencies and individuals. The data base will provide input to ongoing investigations
<br />and modify data collection protocols, if necessary, to facilitate future data integration.
<br />Fisheries investigations in this region of the Colorado River basin have been conducted to
<br />evaluate endangered species, native fishes, and a popular trout fishery. Information collected
<br />includes data on individual fish (e.g., length, weight, tag number), habitat (e.g., depth, velocity,
<br />substrate), and water chemistry. Collection sites have been imprecisely located, using numerous
<br />geographic references, e.g., river miles, distance from dam, meters from shore, tributary mouth,
<br />etc. To integrate these data bases, accurate physical locations, with respect to geographic
<br />position in the landscape, become as important as the specific parameters measured.
<br />Application of GIS
<br />The GCES/GIS data base is being developed as an integrative tool for long-term monitoring,
<br />applied research, and assimilation of information across disciplines. This data base is
<br />structured with three levels of spatial accuracy. The first consists of data referenced to 1:24,000
<br />quadrangle maps, which will achieve the National Map Accuracy Standard of 40 ft in the
<br />horizontal and half a contour interval in the vertical. The second level consists of data photo-
<br />referenced and transferred to the 1:2,400 scale orthophoto grid base maps developed for the
<br />GCES projects. These map products have 2.0-m accuracy in the horizontal and 1.0 m in the
<br />vertical. The third level of accuracy is survey-referenced data with sub-centimeter accuracy.
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