9509

• UCREFRP Catalog Number: 9509
• Author: Hill, C. G.
• Title: Dynamics of Northern Pike Spawning and Nursery Habitat in the Yampa River, Colorado.
• USFW Year: 2004.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

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Catamount Reservoir into the Yampa River. Catamount Reservoir is located on the
Yampa River upstream of Steamboat Springs. Northern pike tagged during May 2003 as
part of another study were captured in the spill basin below Catamount Dam in June of
2003. Another reservoir, Stagecoach Reservoir, located 4.8 km upstream of Catamount
Reservoir, and Elkhead Reservoir located between Hayden and Craig, may also be
contributing northern pike to the Yampa River. We suspect that these reservoirs and the
numerous off channel ponds may actually be contributing more age-O and adult northern
pike to the Yampa River than any riverine backwater spawning habitats.

Evaluation of Barriers
Our intent was to design and evaluate a simple, low maintenance, low cost barrier
that would keep northern pike from entering their spawning ground. Unfortunately, no
barrier tested proved to be completely effective. Nylon seines were easy to install and
conformed nicely to a variety of channel shapes, however, they were subject to damage
from beavers and muskrats. Polyvinyl chloride coated poultry wire performed best of the
materials tested. The larger mesh size available in this material reduced build up of debris
and allowed adequate flows to pass while still thwarting beaver and muskrat damage.
While this wire fabric prevented direct damage to the barrier, it did not stop the animals
from burrowing under the structure and dislodging the sandbags anchoring the fencing in
place. Adding rebar posts in front of the sandbags and through the fencing under the
sandbags appeared to ensure the immobility of the sandbags. Installation of the wire
mesh type of material was labor intensive and achieving a good seal with the bottom of
the backwater was difficult.

Installation of barriers during low fall flows was easier and more convenient, but
the barriers were generally not able to withstand winter ice conditions. Early spring
installations got around some of the difficulties associated with ice formation, but were
not without their problems, the biggest being that barriers needed to be installed before
the ice melted. In our case we had to chip through ice that was 0.6-0.9 m thick in some
places.

Installation of barriers during the early spring in the Yampa River would need to
be done during a relatively narrow window of time before the water temperatures cue
northern pike spawning, especially considering that pike may begin moving into
spawning areas at very low water temperatures. In addition to difficulties with winter
freezing, beavers, and muskrats, the number of possible spawning habitats that would
need to be screened would make it prohibitive to install barriers in all of these sites
during the spring period before spawning begins. Considering the low number of age-O
northern pike we encountered in the river backwaters, a massive barrier building program
may not be logistically possible or economically feasible. While a majority of
landowners indicated a willingness to allow barriers to be built on their property, about
20% were opposed to such actions. If high quality backwaters could not be blocked
because landowner opposition, one would have to question the logic of blocking others.

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