7908

• UCREFRP Catalog Number: 7908
• Author: Valdez, R. A. and R. J. Ryel.
• Title: Life History and Ecology of the Humpback Chub ‎(
• USFW Year: 1995.
• Copyright Material: NO

20 . Executive Summary

Final Report

production can be enhanced in this area as a
way to establish a second spawning population
of humpback chub.

11. Develop and Implemeqt a Long-Term
Monitoring . Program: We concur with
recommendations in the Glen Canyon Dam
Final EIS to develop and implement a long-term
monitoring program. We utge Reclamation to
insure scientific input from present
investigators in development and
implementation of that program.

12. Develop a Temperature Model: Longitudinal
temperature characteristics of the Colorado
River need to be described by season, flow
magnitude, and ramping in order to understand
the effects of selective withdrawal. high spring
releases, and steady summer flows on
temperature and thus on fish assemblages in
both near shore and mainstem habitats.

13. Extend Critical Habitat Designation: We
recommend extending critical habitat of the
humpback chub in Grand Canyon by 10 mi
from Nautaloid Canyon (RM 34) upstream to
RM 24. This area of extension includes the
Fence Fault springs currently being occupied by
the 3D-Mile aggregation (40-60 adults) of
humpback chub. Post-larval chub were
captured in a warm spring in July 1994
indicating successful reproduction.

14. Identify Mainstem Flow Needs for 3D-Mile
Ag2fegation: The elevation of spring sources
and adjacent crevice cover may be critical to
successful spawning by humpback chub near
RM 30. The relationship of these elevations
and mainstem flow need to be described, as well
as flows at which the thermal plume is largest
and most stable for the fish.