7346

• UCREFRP Catalog Number: 7346
• Author: Wick, E. J. and J. A. Hawkins.
• Title: Colorado Squawfish Winter Habitat Study, Yampa River, Colorado 1986-1988.
• USFW Year: 1989.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

1
ME'IHDDS
Fish collections '
Fish collections for transmitter implantation in Winter 1, were made on
five occasions and were completed by the end of October. Fish were collected '
by trammel net, experimental gill net, electrofishing boat, and hook and line
as described in Wick et al. (1985). Netting was conducted from canoe or 18-
foot, flat-bottomed boat powered by an 80-horsepower, Mercury outboard

equipped with a jet shoe. All fish collected were identified and enumerated- '
Catch-per-unit-time was recorded for netting and electrofishing samples. All
Colorado squawfish captured were weighed to the nearest 10 to 50 grams and
measured to the nearest millimeter. Colorado squawfish were tagged with '
orange Orlin tags supplied by USFWS. Previously tagged Colorado squawfish
(recaptures) retained their original tags.
For the 1987 fall study, eight Colorado squawfish originally implanted in

1986 were radiotracked. In addition, one fish was implanted September 9 at ,
Maybell RMI 80.8, and three were implanted September 11, at Lily Park RU 53.2
for radiotracking. An additional six squawfish were implanted in October and

November 1987 for radiotracking during the 1987-1988 winter. Three fish were '
tagged in the Government Bridge study area, one at Maybell and two at Lily
Park.
Radiotelemetrv
Radiotransmitters (radiotags) used in the first year were supplied by

Custom Telemetry and Consulting. Frequencies ranged from 40.6614-40.7022 MRZ- '
Ten of twelve tags purchased were implanted, the remaining two were used as
test tags. Eight tags had a life expectancy of 18 months and were 4.5
centbmters (cam) in length and 1.8 cm in diameter. Four had life expectancies ,
of 24 months and were 6 cam in length and 1.6 em in diameter. Pulse rates
varied from 28 to 45 pulses per minute. All transmitters were pre-tested and
dipped in sterile, melted beeswax prior to shipping by the manufacturer. Upon '
receipt, all tags were starved and tested for 2 weeks prior to implantation.
Transmitters used in 1987-1988 were used from Smith Root Inc. These tags
had a life expectancy of 12-14 months, were 1.6 can in diameter, and ranged
from 6.0-8.5 cam in length. Frequencies ranged between 40.687-40.695 MHz with '
pulse rates of either 50 or 70 per minute. These transmitters were dipped in
melted beeswax prior to implantation.
t
t
d
e
a
Captured adult Colorado squawfish were held in live wells and implan '
capture sites or they were transported by boat to the implantation site, which
was less than 1.5 miles from the capture site. They were anesthetized with a
solution of tricaine methanosulfate (NS 222) and surgically implanted with

radi atYansmi tters according to procedures described by Tyus and McAda (1984). '
Fish were held 10-30 minutes until they recovered from the anesthetic and
released at or near their capture location.
Receivers from three different manufacturers Were used during the study;
Advanced Telen try System's (ATS) procgzwmaable scanning receiver, Smith Root's
Model RF40, and Custom Telemetry and Consulting's Model CE-12. Fish were
tracked by boat when the main river charnel was free of ice using 18-foot '
flat-bottomed jetboat or canoe. Once ice formed on the main channel, a foams'-
8