7610

• UCREFRP Catalog Number: 7610
• Author: Wick, E. J. and J. A. Hawkins.
• Title: Colorado Squawfish Winter Habitat Study, Yampa River, Colorado, 1986-1987
• USFW Year: 1987.
• USFW - Doc Type: Final Report Year 1.
• Copyright Material: NO

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Radiotracking
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Receivers from three different manufacturers were used during the study;
Advanced Telemetry System's (ATS) programmable scanning reciever, Smith Root's
Model RF40, and Custom Telemetry and Consulting's Model CE-12. Fish were
tracked by boat when the main river channel was free of ice using the 18 foot
flat-bottomed jetboat. Once ice formed on the main channel a four-wheel-drive
truck was used on ranch roads where possible. Otherwise fish were tracked on
foot between vehicle access points.
In order to maintain contact, the implanted fish were tracked in October
and November. Beginning December 1 and ending March 21 fish were tracked
systematically on a bi-weekly schedule (Table 1). The two groups of five fish
each [Government Bridge (Group A) and Maybell (Group B)] were alternated as
target and non-target groups on each trip. During each trip four fish from the
target group were monitored for 2.5 hours in each of the following 6-hr
periods: morning 0600-1200 hours (hrs), afternoon 1200-1800 hrs, evening 1800-
2400 hrs, and night 0000-0600 hrs. In addition a fifth fish from the target
group was observed for a full 24-hr period on each trip. During mid-winter on
trips 5 and 6 two fish were monitored for 24-hr periods. In addition, during
each bi-weekly trip all fish in the non-target group were monitored for at
least 30 minutes and usually.up to 2 hours if time permitted.
Fish were initially detected using 1/2 or 1/4 wave whip antennas mounted
on a boat or four-wheel-drive vehicle or hand carried. Once detected the fish
location was triangulated using Smith Root directional loop antennas according
to methods described by Tyus (1987). Survey flags were placed along the bank
marking each transect line. Transects were then checked every few minutes to
determine if the fish remained along the same transects and thus in the same
location. If a fish remained in the same location for 15 minutes it was given
a map location designation on both a field form and a habitat map depicting
key features and fish locations within the area. Target fish observed during
one of the four 6-hr periods would then be observed for an additional 2-3
hours in 5-20 minute intervals. Habitat measurements were performed on all
sites at which fish spent at least 30 minutes. Fish being tracked for the full
24-hr period were similarly observed until a preferred site location was
determined, then triangulation was conducted at least every hour to determine
if any major movement or location change occurred over the 24-hr period.

If more than one radiotagged squawfish was present in an area, data were •
gathered simultaneously on all fish present with the scheduled fish taking
priority.
During the observation period, data recorded on field data sheets
included radiotransmitter frequency, pulse rate, signal strength, weather, air
temperature, river mile location, habitat type, presence of ice cover, time of

each triangulation, actual contact duration, movement type, site location •
recorded on a habitat sketch (map 1D), and presence and distance from other
radiotagged fish.
Habitat type was divided into primary and specific habitat types. Primary
habitats were ; main channel, side channel and tributary stream. Specific
habitats included shoreline, eddy, embayment, run, backwater, pool, riffle,
and rapid (Appendix A).
Fish movement was designated as either stationary (S), active (A), local
(L) or moving (M). "Stationary" was used if no change in fish location could
be detected between or during fish observation periods. A fish was noted as
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