8022

• UCREFRP Catalog Number: 8022
• Author: Muth, R. T., et al.
• Title: Reproduction and Early Life History of Razorback Sucker in the Green River, Utah and Colorado, 1992-1996.
• USFW Year: 1998.
• USFW - Doc Type: 34,
• Copyright Material: NO

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21 mm TL. Drift nets are most effective for capturing small fish larvae passively drifting with
water currents, and the maximum size of fish collected with light traps was limited by the
2- or 4-mm wide entry slits,

Razorback Sucker Captures

LarVal razorback suckers were captured in each year of sampling in the middle and lower
Green River. A total of 1,735 larVae (8-24 mm TL; mean, 12 mm TL) was collected from the
middle Green River and 440 (10-20 mm TL; mean, 13 mm TL) from the lower Green River
(Tables 1 and 2). Numbers captured per year ranged from 20 in 1992 to 1,217 in 1994 for the
middle Green River and from 5 in 1995 to 222 in 1996 for the lower Green River. Ofthe total
number collected from the middle Green River, 1,651 were caught by light traps, 69 by seines, 12
by drift nets, and 3 by dip nets, In the lower Green River, 415 razorback suckers were collected
by light traps and 25 by seines.
Sampling was concentrated in the Escalante, Jensen, and Ouray reaches of the middle
Green River, and in the San Rafael River confluence reach and particularly the middle Stillwater
Canyon reach of the lower Green River. The Escalante, Jensen, and Ouray reaches combined
produced over 99% of the total catch of larVal razorback suckers in the middle Green River
(Table 3). Among those three reaches, 711 razorback suckers were collected from the Jensen
reach (668 by light traps and 43 by seines), 700 were collected from the Escalante reach (661 by
light traps, 29 by seines, and 10 by drift nets), and 318 were collected from the Ouray reach (all
by light traps). Over 90% of all razorback suckers collected from the Escalante reach were
caught in Cliff Creek (the remainder were caught upstream near the Escalante spawning area);
83, 11, and 6% of those captured from the Jensen reach were in collections from Stewart Lake
Drain, backwaters in the Red Wash Launch area (approximately RK 480-481), or Sportsmans
Drain, respectively; and most larval razorback suckers caught in the Ouray reach were from
Greasewood Corral (85%) or the inlet to Old Charlie Wash (14%). Only six razorback sucker
larvae were caught in the Echo Park reach (four by light traps and two by drift nets), and none
was captured from the Island-Rainbow Park reach.

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