7336

• UCREFRP Catalog Number: 7336
• Author: Valdez, R. A. and B. C. Nilson.
• Title: Radiotelemetry as a Means of Assessing Movement and Habitat Selection of Humpback Chub.
• USFW Year: 1982.
• USFW - Doc Type: Grand Junction, Colorado.
• Copyright Material: YES

"

,I
l
~

I.
i
I
I
j
J
i
1
f
I
j
i

,

This is the first known attempt at radiotelemetry with humpback
chub. Tyus et ale (1981) used the method to monitor major movements,
habitat preference and spawning of Colorado squawfish (Ptychocheilus
lucius) and razorback sucker (Xyrauchen texanus) in the Green River.
These investigations were funded primarily by the Bureau of Reclamation
as part of the CRFP (Miller et ale 1982).

MATERIALS AND METHODS

Eight humpback chub (280-366 mm TL) were equipped with internal fish
radio transmitters (Table 1). The fish were captured with the aid of a
220-V, DC electrofishing boat and held in the river in cotton mesh pens.
The fish were captured and equipped with the transmitters in two lots to
evaluate varying periods of physiological adjustment to implant proce-
dures and to the transmitters prior to spawning. The fish were held in
the pens and observed for 72 h for signs of stress or illness caused by
the implant and handling. Four fish (2 males, 2 females) were released
on 3 May 1981, and an additional four (2 males, 2 females) were released
on 30 May 1981. No adverse effects were noted in any of the fish at
release time.

SM-l Fish Modules (radio transmitters) made by AVM Instrument
Company (1979) were surgically implanted in the humpback chub according
to the procedures described by Bidgood (1980) and refined by Tyus et a!.
(1981) for use on Colorado squawfish and razorback sucker. The padlock-
shaped transmitters were 3.0 cm long, 1.2 cm in diameter, and weighed
about 4.5 g (0.6-1. 6% of .the live body weight of the fish). Each trans-
mitter was powered by a 1.3S-V mercury battery with a theoretical life of
90 days and an expected power range of 0.8-2.4 km, depending on
turbidity, conductivity, temperature and instream obstructions. The
smallest available transmitters were used in this investigation because
of the small and laterally-compressed body of the humpback chub. Those
transmitters used by Tyus et ale on squawfish and razorbacks were larger
(11.0 g) and more powerful (215 days).

Each transmitter was implanted surgically in the latero-posterior
portion of the abdominal cavity of the fish. Each fish was first
anesthetized in a mixture of MS222 (Tricaine Methane Sulfonate) and river
water in a laundry tub. The immobilized fish was placed on a wetted
measuring board and a lateral incision 2-3 cm long was made immediately
posterior and slightly dorsal to the insertion of the right pelvic fin.
The transmitter, previously activated and coated with melted bees wax was
inserted into the abdominal cavity. The incision was closed with three
equally-spaced separate surgical sutures using an FS-l surgical needle
and Ethilon black monofilament nylon thread (No. 000). The excess thread
was cut and the surgical knot coated with Krazy Glue™ to prevent it
from becoming untied. The body and gills of the fish were periodically
bathed during implantation with the anesthetic solution to prevent .
desiccation and enhance anesthesia. Surgical implantation usually lasted
2-3 min per fish. After the incision was closed, the fish was gently

I
I .

30