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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because it still maintains a normal hydrograph with natural spring runoff flows. Early
April flows (April 1-15) at Steamboat Springs, Colorado, average 449 cfs and typically
have been between 400 and 600 cfs since 1911 (USGS 2003). Spring runoff usually
begins in mid May with long-term peaks averaging 1,734 cfs, (range: 700 to 3400 cfs).

The main channel is constantly reshaped and redirected because of natural runoff
cycles leading to naturally occurring oxbow channels. Over time these channels are cut
off with re-directed main channel flow to form side channels, backwaters, and eventually
sloughs and isolated ponds. According to Gurtin et al. (2003), backwaters are permanent
bodies of water that are connected to but physically distinct from the main channels or
side channels. Backwaters on the Yampa River typically. have emergent grassy
vegetation along the bank, sometimes extensive aquatic vegetation, and little or no flow.
In addition to backwaters, there are many oxbow lakes and gravel pit ponds located along
the river that are typically isolated, but periodically connect to the river during flood
events. In addition, some of these ponds have narrow outlets (a ditch, culvert, or small
stream) connecting them to the river. Isolated sections of the old river channel, old side
channels that have become backwaters, and off channel ponds are believed to be the
primary spawning habitat for northern pike in the Yampa River (Nesler 1995).
Additionally, large pike populations exist in Stagecoach Reservoir and Catamount
Reservoir, which are reservoirs built on the main stem of the Yampa River above
Steamboat Springs, and in Elkhead Reservoir.

Nesler (1995) identified the area around Craig and upstream as the major location
of suitable backwater pike spawning habitats. Backwaters below Craig were less
common and lacked abundant vegetation and usually became flowing side channels
during increased spring flow periods. Nesler (1995) also concluded that northern pike
found in threatened and endangered fish critical habitat areas below Craig originated in
the better spawning habitats upstream. Our study focused on the Yampa River between
Steamboat Springs and Craig (Figure 1). Primary backwaters studied were located at
river miles 174, 163.8, and 163.3. One gravel pit pond connected to the river at mile 197
was also included in our study. This latter site had a shallow marshy area connected to
the main pond, which in turn was connected to the river. Age-O northern pike were
collected at backwaters located at river miles 197.8, 197, 196.5, 174, 169.1, 163.8, 163.3,
155.3, 155, 154.4, 154.2, and 152.5. The backwater located at river mile 197.8 (Chuck
Lewis State Wildlife Area) had two distinct spawning areas denoted as site A and site B.
Sampling for age-O northern pike at the gravel pit pond took place at the area where
spawning adults were collected and also in the outlet stream connecting the gravel pit
pond with the Yampa River (river mile 196.5). Depth gage readings and detailed habitat
surveys took place at backwaters located at river miles 197.8 (A&B), 174, 169.1, 163.3,
155.3, 155, 154.2, and 152.5. Barriers were installed at sites located at river miles 197.8,
197, and 152.5.

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