7742

• UCREFRP Catalog Number: 7742
• Author: Gilpin, M.
• Title: A Population Viability Analysis of the Colorado Squawfish in the Upper Colorado River Basin
• USFW Year: 1993.
• USFW - Doc Type: A Report to the United States Fish and Wildlife Service, Denver, Colorado.
• Copyright Material: NO

Squawfish Population Viability Analysis --July 1993

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Figure 4.1. A schematic source/sink representation of the Upper Basin of
the Colorado River drainage.

4.4. Minimum Viable Length

A "local" population of the Colorado squawfish (if there be such) occupies
a length of river. Adults migrate to spawn. And fry drift far downstream,
where they grow and whence they return as subadults. How small (short) a
river stretch is required to maintain viability? And, perhaps more
important, what happens when part of the ri ver is turned into a reservoir
(a death trap for juveniles)? A schematic of the dynamics is given in
Figure 4.2. The computer model MVLength allows interactive treatment
of this effect. The internal dynamics are based partially on the results
from the demographic analysis, performed above. It must be understood
that this is a deterministic phenomenon.