7798

• UCREFRP Catalog Number: 7798
• Author: Richardson, S.
• Title: Conceptual Management Plan for Razorback Sucker Habitat Enhancement in Flooded Bottomlands, Escalante Ranch, Jensen, Utah.
• USFW Year: 1994.
• USFW - Doc Type: \
• Copyright Material: NO

Escalante Ranch may
young age classes
more commonly
earn dams and
ntly reduce high
easonally flooded
iting the
gtime congregations
undments and
of these habitats
ecent collections
water habitats
indicate that
ocities are
classes of

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The persistence of adult razorback suckers in the Green River
indicates that habitat conditions are adequate for this life
stage. Therefore, the greatest impact on the recovery of
razorback suckers will occur if the survival of larval and
subadult razorbacks can be improved. Due to the inability of
larval razorbacks to swim against strong currents, drifting
larvae would be better able to persist in habitats of low water
velocity. For this reason, flooded bottomlands and other off-
channel areas are believed to be important as nursery areas for
razorback suckers (Wydowski 1994). However, ertain conditions
must exist and certain factors must be presen in these areas if
they are to provide suitable habitat for larv I and juvenile fish
(Table 1).

Existing or developed off-channel habitats at
provide significant advantages for larval and
of razorback suckers. Off-channel habitat wa
available prior to the construction of mainst
channelization of the river system which curr
springtime flows (Bestgen 1990). Absence of
shorelines and bottomlands may be a factor Ii
recruitment of young razorback suckers. Spri
of razorback suckers found in off-channel imp
tributaries provide evidence of the importanc
(Tyus and Karp 1989). In addition, the only
of razorback sucker larvae have been in slack
(Moode and Irving 1994). Telemetry data also
backwaters and other areas of reduced flow ve
important over-wintering habitats for all age
razorback suckers (Valdez and Masslich 1991).

The importance of wetlands and flooded bottom ands lies in their
productivity. The main channel environment 0 the Upper Colorado
River Basin is very unproductive. Backwaters oxbow lakes,
flooded bottomlands and wetlands are the prod ctive areas in the
upper basin. Production in these areas can b from ten to
several hundred times greater than main chann I areas (Wydowski
1994). This productivity, when combined with warm water
temperatures characteristic of off-channel wa ers, allows young
fish to more rapidly reach a size when predat'on is no longer a
significant factor in survival. Growth of yo ng razorback
suckers in wetland/flooded bottomland habitat has been found to
be nearly four times that of fish in river ba kwater areas (Young
1993). Those larval and young razorback suck rs which do access
protected wetland or bottomland areas are not subject to the main
channel environment where predation and other factors increase
mortality. The development of wetlands, floo ed bottomlands and
rearing ponds at Escalante Ranch will create r enhance habitats
which provide refuge from strong river curren s, provide
protection from predators, promote warm water temperatures and
create rich planktonic and benthic food sourc s resultiD9 from
favorable water conditions'.

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