7171

• UCREFRP Catalog Number: 7171
• Author: Meyer, C. W. and M. Moretti.
• Title: Fisheries Survey of the San Juan River, Utah 1987.
• USFW Year: 1988.
• USFW - Doc Type: Pub. No. 88-1,
• Copyright Material: NO

Introduction
- Colorado squawfish Pt chocheilus Lucius, humpback chub Gila
cypha, bonytail chub G. a egans, and razorback sucker Xyrauchen
texanus are endangered species in the Upper Colorado River Basin.
Colorado squawfish, humpback and bonytail chub are protected under the
Endangered Species Act, while the razorback sucker is a "candidate"
for listing. These fishes historically appear to have been restricted
to the mainstem Colorado River and large tributaries (Behnke and
~ Benson 1980, Holden and Wick 1982). Study of these fishes indicates
that they require the habitat found in these large lotic systems in
order to complete their life cycles (Miller et al. 1982). Human
activities most often identified with the decline in populations of
the endangered fishes include: 1) dam construction; 2) watershed
degradation and water withdrawal, and 3) introduction of exotic
species (Behnke and Benson 1980). Investigation of the impacts of
water resource development on endangered fishes has occurred through
consultation between U.S, Fish and Wildlife Service (FWS) and U,S.
Bureau of Reclamation (BOR), as called for in the Endangered Species
Act.
~ As a major tributary of the Colorado River, the San Juan River
historically supported populations of the endangered fishes (Evermann
and Rutter 1895, Jordan 1891, Sigler and Miller 1963, Holden and Wick
_ 1982, and Valdez and Clemmer 1982). Fish collections from the San
Juan River within the last several decades (Sigler and Miller 1963,
Sublette 1977, VTN 1978, and BLM 1981) indicate a limited size and
~ distribution of endangered fish populations. Investigation of the
impacts of water resource development on endangered fishes in the
Upper Colorado River Basin has largely excluded the San Juan River.
This was due to the limited amount of information regarding the status
of endangered fishes in the San Juan River. Also, human-caused
changes to the river were thought to make the presence of endangered
~ species unlikely. Water withdrawals have changed some of the natural
flow patterns, physical and chemical conditions of the San Juan River,
and human settlements have affected biological and chemical properties
of the river (U .S. Bureau of Reclamation 1982). More recently,
consultation between BOR and FWS on further water development
activities in the San Juan River Basin (Animas and LaPlata Rivers)
~ indicated a survey of the river was needed to assess the potential for
recovery of endangered fishes.
A cooperative agreement was established between BOR and the
States of New Mexico and Utah to study the San Juan River in 1987.
The New Mexico Department of Game and Fish studied the river from
~ Farmington, New Mexico to Four Corners, approximately 60 river miles
(RMI). Investigations in the transition zone between the river and
- Lake Powell from the confluence of Grand Gulch to Piute Farms Marina
on Lake Powell, approximately 16 RMI, were conducted by BOR. The Utah
Division of Wildlife Resources (UDWR) studied the river from Four
- Corners to the confluence of Grand Gulch, approximately 120 RMI. The
~ results of UDWR's and BOR's work are reported herein.
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