8123

• UCREFRP Catalog Number: 8123
• Author: Wydoski, R. S.
• Title: Coordinated Hatchery Facility Plan
• USFW Year: 1994.
• USFW - Doc Type: Need for Captive-Reared Endangered Fish and Propagation Facilities.
• Copyright Material: NO

Colorado squawfish Considered stable for most presumptive stocks. Upper
Colorado River stock (upstream from Westwater Canyon)
is very low in number. Presumptive stock in the
Gunnison River is extremely low and is declining.
The Redlands Irrigation Diversion Dam in Grand
Junction, Colorado prevents migration of squawfish
from the Colorado River into the Gunnison. This
species has been extirpated from the Colorado River
from the Highline Irrigation Diversion Dam upstream
to Rifle, Colorado.
E. Priorities for Captive Propagation Among Species and Among Presumptive
Stocks. Priorities among the endangered fish species were based on their
relative status and trends, particularly where the probability of
immediate extinction in the wild appeared high.
The razorback sucker was ranked number 1; bonytail - 2; humpback chub - 3;
and Colorado squawfish - 4 (Table 3). The number "1" indicates the
highest priority and the number "4" indicates the lowest priority for
either species or stocks. Assignment of priorities for stocks within
species was more difficult because all stocks may be important in the
recovery effort. Therefore, an overlap in priorities occurred among some
stocks within a species.
Immediate steps should be taken to maintain the species in refugia and
produce F, progeny as broodstocks to produce captive-reared fish for
research studies and potential future augmentation and restoration
stocking. This action can be viewed as a "life insurance policy to
prevent extinction of a species".
1. Razorback Sucker. The razorback sucker was assigned "Priority 1"
among the four endangered fishes because all stocks are declining
rapidly and little or no recruitment has been documented. The
razorback sucker is at risk of becoming extirpated in the Upper
Colorado River Basin due to the trend of declining adult fish numbers
and the lack of recruitment in most reaches of the Colorado and Green
river subbasins. The only exception to this statement is the stock in
the middle Green River between the confluence of the Duchesne and
Yampa rivers where small fish (< 475 mm) have been captured indicating
that this stock has some recruitment (Modde et al. 1993). However,
the razorback sucker is also a species with a high potential for
recovery among upper basin wild stocks. Therefore, the four stocks of
razorback sucker were assigned equal priorities (Priority 1) because
all presumptive stocks may be important in the recovery effort (Table
3). The Colorado River Fishery Project staff in Vernal, Utah has the
responsibility for developing an augmentation stocking plan for the
Green River subbasin during Fiscal Year 1994. The Colorado Division
of Wildlife will develop a similar plan for the Colorado River
downstream from Palisades, Colorado and restoration stocking plans for
the reach above Palisades and for the Gunnison River upstream of the
Redlands Irrigation Diversion Dam.
This species has exhibited a dramatic decline in both the Colorado and
Green Rivers. Razorback sucker captures from the upper Colorado River
(River Mile 152.8 to 185.1) between 1974 and 1991 declined from a high
14 a