Pacific and Western Brook Lamprey
Coastal Oregon populations of Pacific lamprey Lampetra tridentata and western
brook lamprey L. richardsoni are considered depressed due to
habitat loss and passage problems (Close et al. 2002, Nawa 2003, ODFW
2006). Dam counts at Winchester, Bonneville, and Leaburg dams show a
dramatic decrease from historical levels (Kostow 2002, Nawa 2003, ODFW
2006). In 2003, eleven environmental groups petitioned the U.S. Fish and
Wildlife Service to list Pacific, western brook, river and Kern brook
lamprey as endangered in the Pacific Northwest and California (Nawa
2003). Even though the petition cited multiple reasons for habitat loss,
the U.S. Fish and Wildlife Service determined the petition did not
contain adequate information to warrant a listing (Federal Register, 69
(27 December 2004) 77158-77167). The Oregon Department of Fish and
Wildlife recently reviewed the status of western brook and Pacific
lamprey and found populations to be ‘at risk’ of extinction (ODFW 2006)
due to habitat loss, passage barriers and pollution. However data
necessary to conduct a thorough and detailed assessment are lacking.
Much of the data lacking are critical to the effective management and conservation of
Oregon’s coastal lamprey species. The Columbia River Basin Lamprey
Technical Workgroup (CRBLTW 2005) and members of Columbia River
Inter-Tribal Fish Commission (CRITFC 2004) have identified and
prioritized critical data gaps for Pacific lamprey, many of which also
apply to western brook lamprey. Among these are 1) methods to assess
distribution and abundance of all life stages and appropriate techniques
for monitoring population status; 2) population structure and
delineation; 3) population dynamics; 4) basic biology including
interspecific and community level relationships; 5) limiting factors and
threats including passage issues, and 6) habitat needs and requirements.
and Habitat Associations
In 2004 and 2005 the
Native Fish Investigation Project conducted a study to identify habitat
variables associated with spawning Pacific and western brook lamprey in
order to infer distribution throughout coastal Oregon. The objectives of
this study were to
1) Determine distribution of spawning
Pacific and western brook lamprey in the Smith River basin;
2) Describe redds of both species; and
3) Describe associations of spawning Pacific and western brook
lamprey in relation to habitat unit and reach scale habitat characteristics.
In general the results of the study show,
1) Reach scale habitat variables were
correlated with stream size and elevation and were the best descriptors of
2) Unit type and dominant substrate were
weakly associated with spawning lamprey; and
3) Other ecological factors (i.e.
presence of ammocetes, network distance from rearing or aestivation
sites) may have had a stronger influence than habitat structure.
See 2005 final report for complete results
and references cited above.
Freshwater Residence of Adult Pacific Lamprey
In 2006 we initiated a
study to continue the examination of the adult freshwater phase of the
Pacific lamprey life history by describing the duration, locations and
habitat use of aestivating lamprey. Adult Pacific lamprey re-enter
freshwater late April through June, aestivate 6-10 months, and spawn the
following spring. It is unknown where in the watershed lamprey
aestivate, what habitats they occupy during aestivation, and whether
they make another significant migration to the gravel beds before
spawning. Our study aims to better describe this life history trait and
to further describe habitat features associated with aestivation.
Description of this habitat can be used to better focus conservation
efforts for this species. Our approach is to implant radio tags at Smith
River Falls (Umpqua Basin) in 40 adult lampreys returning from the ocean
in the spring and track individuals throughout the following year using
radio telemetry. We will describe movement throughout the year, the
physical characteristics of Pacific lamprey over-winter habitats and
document the location relative to spawning grounds.
Annual Reports and Publications:
Gunckel, S.L, K.K. Jones, and S.E. Jacobs.
2009. Spawning distribution and habitat use of
adult Pacific and western brook lampreys in Smith River, Oregon.
Pages 173-190 in L. R Brown, S.D. Chase, M.G. Mesa, R.J. Beamish and P.B. Moyle, editors. Biology, management and
conservation of lampreys in North America. American Fisheries Society, Symposium 72, Bethesda, Maryland.
Gunckel, S.L., K.K. Jones, and S.E. Jacobs. 2006.
Spawning distribution and habitat use of adult Pacific and western brook lamprey in Smith River, Oregon. Oregon
Department of Fish and Wildlife, Information
Report 2006-1. Corvallis.
Oregon's Lampreys: Natural History, Status, and Analysis of Management Issues
Oregon Native Fish Status Report (2005)