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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Introduction
Northern pike (Esox lucius) in North America are native to the Missouri River
drainage, the upper part of the Mississippi River drainage, parts of the Ohio River
drainage, Alaska, and Canada south of the Arctic Circle (Crossman 1978). Since 1850,
the distribution of northern pike has expanded beyond their native range and they are now
widespread throughout North America (Crossman 1978). The development of numerous
impoundments has provided the opportunity for many intentional and illegal
introductions (Fuller et al. 1999). The reason for most northern pike introductions has
been to create new sport fishing opportunities, but they have also been introduced to
control populations of abundant prey species (Mann 1996).

Introductions of northern pike in some areas have hampered fishery management
actions resulting in serious losses to local and regional economies. Previously productive
trout reservoirs in some areas have become so dominated by northern pike that stocked
trout no longer show up in angler creels (Bergersen 2001). Introductions of northern pike
in Lake Davis, California and south central Alaska pose a potential. threat to commercial
salmon fisheries near these areas. Northern pike escapement from impoundments to
downstream rivers that contain threatened and endangered fish adds an additional threat
to the recovery of threatened and endangered fish (Tyus and Beard 1990). Attempts to
eradicate northern pike from reservoirs and drainage basins have met with little success
(Bergersen 2001; California Department ofFish and Game 2000).

In contrast, northern pike populations within its native range are declining due to
loss of spawning and nursery habitat (Casselman and Lewis 1996). Typical northern pike
spawning habitats in rivers are marshy areas connected to rivers (Bry 1996). The timing
of spawning is highly variable throughout North America and has been noted to take
place anywhere from February to June (Billard 1996). Northern pike typically spawn at
water temperatures of 7.8 - 11.70 C soon after ice-out (Casselman and Lewis 1996;
Farrell 2001), but may enter spawning areas at temperatures as low as 0.6 - 4.40 C
(Franklin and Smith 1963). Individuals typically spawn over a period of 5 or 6 days, but
low temperatures can extend the spawning period to as many as 19 days (Franklin and
Smith 1963).

The Yampa River is home to the Colorado pikeminnow (Ptychocheilus lucius),
humpback chub (Gila cypha), bonytail (Gila elegans), and razorback sucker (Xyrauchen
texanus), which are currently listed as federally endangered species. As a relatively free-
flowing river, it is an important area for efforts to recover these endangered native fish.
The section of the Yampa River downstream of Craig, Colorado (river mile 139) has
been identified as critical habitat for threatened and endangered fish, and northern pike
and other nonnative fish inhabiting this reach have been identified as major predatory
threats to native fish (Nesler 1995). The northern pike's first arrival in the Yampa Valley
occurred with its stocking in Elkhead Reservoir, a reservoir located on a tributary stream
to the Yampa River. As early as 1979 northern pike escaped from Elkhead reservoir and
have proliferated in the Yampa River ever since (Tyus and Beard 1990).

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