7978

• UCREFRP Catalog Number: 7978
• Author: Tyus, H. M.
• Title: Chemoreception, Imprinting, and Propagation of Colorado Squawfish and Razorback Sucker
• USFW Year: 1992
• USFW - Doc Type: a Plan of Study
• Copyright Material: YES

1

t
i

INTRODUCTION

The Endangered Species Act (ESA) of 1973 provided new policy and funding to
Federal and State agencies involved in protection and recovery of endangered
animals and plants. However, little was known of the ecological requirements
of many endangered species, and wildlife management concepts were more
oriented toward sport hunting and fishing. In the American Southwest, progress
toward recovery of endangered Colorado River fishes has been constrained by a
pauc;ty of ;nformat;on on the;r life history requ;rements, the;r rar;ty, and
the harshness of the environments in which they live. In addition, current
habitat use information may only reflect marginal use because the species have
been in decline for many decades. Thus, caution must be used when interpreting
current habitat use data.

Under the ESA, recovery must be accomplished within an ecosystem context.
It is imperative that ecological aspects prevail in endangered species
management, and an understanding of biotic and abiotic factors limiting the
distribution and abundance of the target species be well understood and
incorporated into any management attempt. Because remaining populations of
endangered species are fully protected under the ESA, it is incumbent upon
management agencies to demonstrate that proposed management or recovery
actions will not further jeopardize the existence of a listed species.

This paper presents a recommended course of action for the study of
chemoreception and imprinting in Colorado squawfish and razorback sucker in
the upper Colorado River basin. We address the potential role of these
mechanisms in the life cycle of these fishes, and the application of this
knowledge to recovery plans. Study objectives include the following:

To determine the mechanism by which adult Colorado squawfish and razorback
sucker locate suitable spawning areas, and to evaluate the role of olfaction
in habitat selection.

To identify the roles of imprinting, learning, and genetic control on the
reproductive cycles of Colorado squawfish and razorback sucker.
To explore means by which new populations of Colorado squawfish and razorback
sucker may be established using innate behavioral mechanisms.

BACKGROUND:

Minnows and suckers belong to the Suborder Cyprinoidei. The fish family
Cypr;n;dae, or minnows, cons;sts of about 275 genera and over 1600 spec;es and
is the largest and most diverse in the world. The closely allied suckers,
family Catostomidae, consists of 12 genera and 58 species. Spawning migrations
occur in the Cyprinoidei and some of these are well-known in various parts of
the world. In North America, potamodromous migrations of catostomids to
specific spawning streams or reaches have been reported for many years (e.g.,
Dence et ale 1940, Dence 1948, Raney and Webster 1942). Similar migrations
have also been reported in Asia for various minnows (Nikolskii 1961, Breder
and Rosen 1966).

Several experiments have demonstrated that some minnows exhibit an
exquisite sense of smell and can detect minute quantities of dissolved
substances (Pfeiffer 1963, Kleerekoper 1969, Smith 1975). The use of chemical

10

-