Draft Baseline Report - Pallid Sturgeon Section

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HISTORIC DATA NOT BEING COLLECTED DURING THE PROGRAM The Program does not envision stocking the lower Platte River. In October 1997, 412 ten -inch pallid sturgeons were stocked in the lower Platte River adjacent to the Louisville State Recreation Area, which is located approximately 12 miles above the mouth of the Platte River. The stocked pallid sturgeons were the progeny of a brood stock population maintained by the Missouri Department of Conservation. Each of the stocked pallid sturgeon has two unique numbered tags, which include a small internal micro -tag and a yellow 2- inch -long external tag attached to the left pectoral fin. Anglers who catch a tagged pallid sturgeon are asked to leave the external tag on the fish and report the tag number and location to the Missouri Department of Conservation (Zuerlein 1998). Information obtained from the anglers will be used to document movement of pallid sturgeon in the lower Missouri River basin. Contaminant load No background information exists on contaminant loads in pallid sturgeon, and as a result only broad inferences may be drawn from the results of the analyses performed by Ruelle and Keenlyne (1993). Ruelle and Keenlyne analyzed contaminant concentrations in three Missouri River pallid sturgeon. Two of these fish were captured in the upper Missouri River in North Dakota, an area isolated from the lower river by mainstem dams. The third was captured from the lower Missouri River in Nebraska, approximately 60 miles below the confluence with the Platte River. The Nebraska fish was a 10 -year old female that was not yet sexually mature. Samples were taken of gonad, liver, kidney and muscle tissue. The Nebraska fish was found to contain concentrations of DDT, chlordane, dieldrin, cadmium, mercury and selenium, and particularly PCB's (which have been found to reduce reproductive success in fish) high enough to suggest that these individual contaminants or the combination thereof may be affecting pallid sturgeon health and reproduction ( Ruelle and Keenlyne 1993). Habitat Suitability Criteria for Prey species A two -year study by the University of Nebraska, from 1986 -1988 developed microhabitat suitability index criteria for the dominant species of fish and macroinvertebrate taxa of the lower Platte River, which may be used as food by pallid sturgeon. Methods and results are described by Peters et al. (1989). The study reach extended from the confluence of the Platte and Loup River (RM 101) downstream to the mouth of Salt Creek (RM 25). Most sampling was conducted between RM 59 and 78, which included instream flow incremental methodology (IFIM) transects established by the Nebraska Game and Parks Commission at RM 69. Forage fish were sampled weekly, using pre - positioned electrofishing grids placed along 100 -meter transects. Quantitative measurements of depth, current velocity, cover and substrate were collected for 10 species of fish and 18 invertebrate taxa. Using similar methods, Holland and Peters Draft Baseline Report — Pallid Sturgeon Section 17