6027

• UCREFRP Catalog Number: 6027
• Author: Tyus, H. M., R. L. Jones and L. A. Trinca.
• Title: Green River Rare and Endangered Fish Studies, 1982-85
• USFW Year: 1987.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

years, but fossils of Gila and Ptychocheilus similar to our existing native
fishes have been traced to the middle Pliocene, or about B million years ago.
METHODS
SPRING COLLECTIONS
Spring (April and May) collections were initiated in Green River in 1980
to implant radiotransmitters in adult Colorado squawfish. This work was later
expanded into a Spring Survey Program since it pcoved to be an effective means
of collecting life history, distribution, and abundance data on rare and
endangered fishes. Catch data (fish catch per hour electrofishing) from
spring surveys was collected April 15 - June 1 for each river stratum
(relatively homogeneous river reaches). Strata are defined as follows, with 0
RM (0 KM) calculated at the mouth of each river (Figure 2):
1. Green River
Stratum Length (km) Length (mi) Range (mi)
A 114 72 22- 93.9
B 59 37 94- 131.9
C 38 24 132- 156.9
D 86 54 157- 211.9
E 59 37 212- 249.9
F 112 70 250- 319.9
G 40 25 320- 345.0
2. Yampa River
Stratum Length (km) Length (mi) Range (mi)
8 53.0 33.0 91.0- 124.0
7 4.0 2.0 88.7- 91.0
6 47.7 29.9 58.8- 88.7
5 5.2. 3.2 55.6- 58.8
4 6.4 4.6 51.0- 55.6
3 9.6 6.0 45.0- 51.0
2 40.0 25.0 20.0- 45.0
1 32.0 20.0 0.0- 20.0
10