7821

• UCREFRP Catalog Number: 7821
• Author: Hamilton, S. J., et al.
• Title: Evaluation Of Toxicity To Larval Razorback Sucker Of Selenium-Laden Food Organisms From Ouray NWR On The Green River, Utah.
• USFW Year: 1996.
• USFW - Doc Type: \
• Copyright Material: NO

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INTRODUCTION

Since the discovery of contaminated irrigation return waters in the San Joaquin Valley
of central California in 1982 (Ohlendorf et al. 1986, Saiki 1986), the Department of the
Interior (DOl) initiated a program to identify other areas in the western U. S. that have water
quality problems induced by irrigation drainage (Feltz et al. 1991). These investigations
focused on irrigation drainage facilities constructed by DOl, where the receiving water was a
national wildlife refuge, or had the potential to adversely impact migratory birds or
endangered species.

The middle Green River basin located in northeastern Utah was identified as one area
needing further study. The middle Green River basin provides sensitive habitats for two
endangered fish species, Colorado squawfish (Ptychocheilus lucius) and razorback sucker
(Xyrauchen texanus). Two other endangered species fish are also known residents of the
Green River, the humpback chub (Gila cvpha) and bony tail (Gila eleeans). The middle
Green River is defined as the drainage area consisting of the Green River and its tributaries
between Flaming Gorge Dam and the city of Green River, Utah (Figure 1).

Several researchers have documented low reproduction in razorback sucker in the
upper Colorado River basin (Lanigan and Tyus 1989, Tyus 1987. Wick et al. 1982). In
1991, young-of-year razorback sucker were positively identified in a collection from the
lower Green River near Hell Roaring Canyon (Gutermuth et al. 1994). In 1995, 28 juvenile
razorback sucker (74 to 125 mm) were collected in a wetland on the Ouray National Wildlife
Refuge (NWR) almost directly across the Green River from Sheppard Bottom (Modde 1996).
The major causes for the decline of endangered fishes in the upper Colorado River basin
include physical and water quality factors such as dams, which reduce water temperature,
decrease turbidity, alter seasonal and annual flow patterns, and reduce habitat for adult and
larval fish such as spawning bars and flooded bottomlands (USFWS 1987). In addition,
numerous introduced fish species have increased predation and competition (USFWS 1987,
Karp and Tyus 1990, Marsh and Brooks 1989, Ruppert et al. 1993). In certain situations,
predation by macro invertebrates on larval razorback sucker may be adversely affecting their
survival (Horn et al. 1994).

A DOl irrigation project near Jensen, Utah, returns drain water to Stewart Lake
Waterfowl Management Area and the Green River. Extensive irrigation outside the DOl
project influences water quality in Ashley Creek and the Duchesne River, tributaries of the
Green River downstream from Stewart Lake. Also downstream. the Ouray NWR uses
surface and groundwater from irrigation. Analysis of water, bottom sediments, and biota
collected from the middle Green River basin since 1986 have confirmed the presence of
boron, selenium, and zinc at concentrations that could be potentially harmful to fish and
wildlife (Stephens et al. 1988, 1992, Peltz and Waddell 1991, Waddell and Stanger 1992).

Based on the DOl studies in the middle Green River, the inorganic of principle
concern is selenium because of its propensity for food-chain bioaccumulation (Bennett et al.