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

9

Production and Recruitment to Target Size

No reliable estimates are available for number of females involved

in spawning, number of ova produced, fertilization success, hatch,

or number of swim-up larvae produced in the Yuma Cove backwater.

Theoretical estimates could be derived on the basis of field and

hatchery data, but these could not realistically be extrapolated to

the situation at Yuma Cove. Further, estimates of juvenile

mortality rates also are unavailable (see below). However, samples

of razorback sucker were removed for genetic (mtDNA and allozyme)

analyses, which should provide a minimum estimate of the number of

females that produced the Yuma Cove fish. These last data will be

used to guide future propagation activities so that cove-reared

fish adequately reflect the genetic diversity of the adult

population in Lake Mohave.

Three independent, multiple census (Ricker 1975) estimates of

juvenile razorback sucker abundance were made using mark-recapture

data collected from 16 June to 29 July (Table 2). An "original

Schnable" estimate was 306 fish; a "modified Schnable" estimate was

276; and a "Schumacher-Eschmeyer" estimate was 329 fish (95%

confidence limits of 251-472 [t = 2.571, df = 5; Snedecor and

Cochran 1967) for the last estimate). The total number of fish

removed to Davis Cove during sampling subsequent to 22 July and

reclamation on 25 November was 296 individuals (298 total fish