8142

• UCREFRP Catalog Number: 8142
• Author: Horn, M. J.
• Title: Nutritional Limitation of Recruitment in the Razorback Sucker ‎(
• USFW Year: 1996.
• Copyright Material: NO

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(average 19.5 m), volume at full pool was 1.85 X 1012 m3 and mean turnover time for the

reservoir 68 d under normal operating criteria (Paulson et al. 1980). Annual reservoir

fluctuations are on the order of 3-5 vertical meters. Cold hypolimnetic water from Lake

Mead (12-13 oC) is delivered through Hoover Dam and in turn through Davis Dam for

downstream uses and power generation. This cold inflow often dominates the

temperature of Lake Mohave in winter and forms strong density currents in summer.

Compared with other Colorado River reservoirs (paulson et al. 1980), Lake Mohave is

mesotrophic in overall productivity (Priscu et al. 1981; Priscu 1982).

Yuma Cove (Figure 3) has a surface area of 0.85 to 2.1 ha depending on reservoir

level. It was originally isolated by a gravel spit formed by wave action and longshore

currents in Lake Mohave. The spit was enhanced and artificially stabilized with heavy

equipment in 1991 as part of razorback sucker recovery efforts. The cove averages 3.0 m

deep at full pool and remains connected to the reservoir by interflow through coarse

gravels of the spit (Marsh and Langhorst 1988).

Some chemical and biological data for the reservoir and Yuma Cove are

compared in Figures 4-6. Conductance in the cove is higher and more variable, patterns

are similar but temperatures may average 2.0oC higher, and dissolved oxygen tends to

remain as high or higher than in the reservoir during spring. The cove also tends to

average higher than the reservoir in plankton density, although species composition is
similar.