7799

• UCREFRP Catalog Number: 7799
• Author: Modde, T. and D. Irving.
• Title: Conceptual Management Plan for Habitat Enhancement In Old Charley Wash.
• USFW Year: 1994.
• USFW - Doc Type: \
• Copyright Material: NO

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1. determine whether razorback sucker adults will access Old Charley
Wash during flood stage through the fish access/water control
structure,

2. determine if larval razorback sucker can naturally access Old
Charley Wash,

3. determine the composition of, the sequence of appearance and
growth of larval fishes in Old Charley Wash,

4. determine the relative abundance and diet of potential predators
of underyearling razorback sucker in Old Charley Wash,

5. record temperature, dissolved oxygen, water elevation, and gross
estimates of zooplankton through time, in Old charley Wash,

6. monitor sizes, growth and composition of fishes accessing Old
Charley Wash during the spring and summer months,

7. evaluate the success of the newly constructed fish access
structure to collect adult and underyearling fishes when water is
drained in October, and -~.

8. determine the genetic diversity of any underyearllng razorback
sucker collected when draining the bottomland.

study Area:

Old Charley Wash, Ouray National Refuge

study Methods/Approach:

Larval fish will be collected with light traps from Old Charley Wash
coincident with razorback larval emergence. Spawning will be
determined by monitoring radio transmitter implanted razorback sucker.
Light traps will continue to be used to determine the sequence of
larval fishes into Old Charley Wash and evaluate fish composition
through time. If it appears that insufficient flooding occurs to
access emigrating razorback sucker larvae, additional larvae will be
collected with light traps from outside of Old Charley Wash and
transferred to the Wash after being marked with an otolith dye.
During the flood stage, the trap on the fish access structure will be
monitored to determine if adult razorback sucker will move through the
fish control structure.

Monthly fish collections will be made with and electroshocker to
determine the composition of larger fishes in the flooded bottomland.
Potential predators will be sacrificed and stomachs removed to
determine ration composition. Total lengths will be recorded from all
underyearling fish to determine growth rates. Temperature,
zooplankton volume, and dissolved oxygen and water elevation in the
bottomland (an adjacent river) will be determined at two week

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