1108

• UCREFRP Catalog Number: 1108
• Author: Valdez, R. A.
• Title: Fisheries Biology And Rafting Annual Summary Report - 1987
• USFW Year: 1988.
• USFW - Doc Type: ‎(Contract no. 6-CS-40-03980)‎.
• Copyright Material: NO

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INTROOOCTIOO

This document is the Annual Summary Report for 1987 submitted to the Bureau of
Reclamation (BOR) in fulfillment of Contract No. 6-CS-40-03980, entitled
Fisheries Biology and Rafting. Eight progress reports were submitted during
the course of the investigation, one for each of eight sample trips. This is
the second of three scheduled Annual Summary Reports; the first Annual Summary
Report (Valdez 1987) is available from BIOjWEST, Inc.

Objectives
The objectives of this investigation are to:

1. Determine spawning locations of endangered fishes in Cataract Canyon,
2. Determine whether humpback chub populations exist in Cataract Canyon,
and
3. Describe to what extent BOR's operation of Lake Powell influences
nursery habitat of Colorado squawfish in the Gypsum Canyon area.

Background

This investigation was conducted as part of BOR's ongoing program on endangered
fishes of the upper Colorado River basin. That program is part of the respon-
sibili ty of federal agencies as prescribed by the Endangered Species Act of
1973, as amended, to protect and, where possible, promote the recovery of these
fi shes.

Since 1978, BOR, in conjunction with the u.S. Fish and wildlife Service (FWS),
has funded and conducted these studies to gain a better understanding of the
life history and living requirements of the endangered Colorado squawfish
(Ptychocheilus lucius), humpback chub (Gila cypha), and bonytail (Gila
elegans), as well as the federal candidate species razorback sucker (Xyrauchen
texanus). A major portion of this effort by BOR has been to fund the ongoing
Colorado River Fisheries Project (CRFP), being conducted by the FWS.

Generally, the investigations of CRFP have included all of the range of the
endangered fishes in the upper basin, except for some regions that are not part
of the sampling design, or require special equipment because they are difficult
to access and sample. One such area is Cataract Canyon, located between the
confluence of the Colorado and Green rivers, and upper Lake Powell (Figure 1).
Cataract Canyon is a 16-mile reach of whitewater within Canyonlands National
Park adrrdnistered by the National Park Service.

Attention was first drawn to the endangered fishes of upper Lake Powell in
April 1980, when 45 adult Colorado squawfish were captured near Gypsum Canyon
during a study by the utah Cooperative Fishery Research Unit (Persons et al.
1982, Valdez et al. 1982). The objective of the investigation was to assess
spawning success of striped bass in the portion of the Colorado River flowing
into Lake Powell. The squawfish were captured coincidentally in gill nets set

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