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

Trautman (1957) identified limited access to spawning areas as the main factor
leading to a decrease in northern pike populations in Lake Erie. Where backwater
spawning habitats have a single access point to the river, one possible approach for
managing northern pike populations may be restricting access to spawning sites. The
purpose of our study was to investigate northern pike spawning and nursery habitat in the
Yampa River to determine whether barriers to spawning habitat could be an effective
management technique for reducing northern pike numbers. To evaluate the
effectiveness of barriers, we determined the timing of spawning, assessed the abundance
and quality of spawning and nursery habitat, evaluated the effects of variable spring
runoff flows on spawning and nursery habitat, and determined recruitment levels of age-O
northern pike. Our evaluation of barriers included assessing the effectiveness of different
barrier designs and installation times, and determining the feasibility of installing barriers
throughout the study area.

Goal and Ob1ectives

Goal: to reduce spawning and reproduction by northern pike in Yampa River habitats,
effecting a reduction in the abundance of pike in critical habitat for endangered fishes
downstream.

Objectives:
1. To determine the feasibility and logistic requirements of using temporary
screening with low-cost materials to prevent access to these habitats by spring
spawning, adult northern pike on a reach-wide scale from Craig to Steamboat
Springs.
2. To implement exclusionary screening of potential pike spawning habitats on a
reach-wide scale and mechanically remove pike from any habitats where access
by pike to screened spawning habitats has been gained due to temporary screen
failure.
3. To monitor effectiveness of exclusionary screening of pike spawning habitats
using trend analysis of capture rates for northern pike during ongoing mechanical
removal efforts within critical habitat in the Yampa River downstream.
4. To evaluate and recommend design improvements in existing irrigation diversion
and return systems to reduce potential northern pike spawning habitat or facilitate
screening control.

Study site
The Yampa River is located in northwest Colorado and originates at an elevation
of 2,287 m. It joins the Green River in Dinosaur National Monument near the
ColoradolUtah border. The aquatic communities transition from coldwater to coolwater
between Hayden (River mile 170) and Craig (River mile 139), Colorado, and from
coolwater to warmwater between Craig and Duffy Mountain (River mile 118), Colorado
(Nesler 1995). The Yampa River is a unique stream in the upper Colorado River basin

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