7063

• UCREFRP Catalog Number: 7063
• Author: Berry, C. R., Jr.
• Title: Homing Instinct of Colorado Squawfish as Determined by Olfactory Response.
• USFW Year: 1984b.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

test their response periodically until mature. One group of 500
fry will be exposed to morpholine from hatch to one month of age,
approximately the time spent in the Yampa River by wild, recently
hatched fry (Archer and Tyus 1984). Another group will be
treated similarly, but not exposed to morpholine, to serve as a
control. Morpholine is a heterocyclic amine that does not occur
in natural waters , is infinitely water-soluble, relative stable,
and is perceived at low thresholds by salmon (Wisby 1952). Fish
will be tested for morpholine recognition after growth to a
sufficient size for implanting EEG electrodes (probably at 18
months of age) and every 6 months therafter until mature. The
responses of the imprinted and nonimprinted specimens (12 fish
for each group) will be compared using a Mann-Whitney U test.
Squawfish mature at 5 to 7 years of age, a captive fish held
in optimum growing conditions might reach maturity at 3 years of
age (J. Valentine, Fishery Biologist, U. S. Fish and wildlife
Service, Salt Lake City, Utah, Personnal communication).
Imprinted fish need not be mature to recognize the imprinting
chemical (Dizon et al. 197.5), although mature, ripe fish elicit a
more pronounced response (Nara and Brown 1979).
EXPECTED RESULTS
Results from these tests will provide the best information
possible from available stocks of Colorado squawfish on ability
of the species to identify specific water by sense of smell and
presumably then to return to home waters in the wild. In
addition, information will be gained on the influence of age and
sexual maturity on olfactory recognition of home waters.
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