8071

• UCREFRP Catalog Number: 8071
• Author: Horn, M. J. and P. C. Marsh.
• Title: Production of Razorback Sucker in a Backwater at Yuma Cove, Lake Mohave, Arizona and Nevada, 1992.
• USFW Year: 1993.
• USFW - Doc Type: Tempe, Arizona.
• Copyright Material: NO

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On each sampling date, all fishes were enumerated and measured.

Larval samples collected from 26 February through 22 April were

preserved for laboratory analyses, as were any mortalities. Adult

razorback suckers were measured, weighed, and scanned to determine

PIT tag identification number, then released into Lake Mohave.

RESULTS and DISCUSSION

Growth of Cove-produced Razorback Sucker

Early post-larval razorback suckers first appeared in samples

collected 26 February 1992; these averaged 11.0 rom TL (Table 1,

Figure 1) and were about 12 to 15 days post-fertilization (6 to 9

days post-hatch [Minckley and Gustafson 1982, Marsh 1985J). Mean

TL increased exponentially over succeeding months, and young fish

developed through the late post-larval stage into juveniles during

May. Length continued to increase until mid-July, when growth

slowed to essentially nil for about 2 weeks (Figure 1), presumably

as a result of mid-summer stresses associated with falling lake

level, increased temperatures, and reduced dissolved oxygen

(Figures 2-4). Growth resumed in early August and TL increased

approximately linearly through the final sampling in late November.

Average TL attained during the 9-rnonth post-hatch period was 35.4

cm (assuming linear growth: about 4 crn/month or 0.028 cm/day), with

the largest individual reaching 39.1 crn (Table 1, Figure 1).