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MetaData for Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
- Originator: Starcevich, S.J and S.E. Jacobs
- Publish Date: 2008
- Online Link: None
- BPA Project #:
- Agency: Oregon Department of Fish and Wildlife
- Name: Cedric Cooney
- Job Position: Natural Resources Data and Systems Manager
- Telephone: 503-947-6094
- E-Mail Address: firstname.lastname@example.org
- Abstract: Hood River bull trout are thought to exist as two independent reproductive units (USFWS
2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local
population is isolated above Clear Branch Dam, which provides limited downstream fish
passage during infrequent and sporadic periods of spill and no upstream passage. Bull trout in
this population inhabit Laurance Lake Reservoir and tributaries upstream of Clear Branch Dam.
The Hood River local population occurs in the mainstem Hood River and Middle Fork Hood
River downstream of the Clear Branch Dam and a small number of adult bull trout migrate each
year into the Hood River from the Columbia River (Figure 1). The status of both populations is
extremely precarious. The Clear Branch population is at risk of a random extinction event due
to low numbers, negative interactions with non-native smallmouth bass, isolation and limited
spawning habitat (USFWS, 1998). The Hood River population also appears to be small and is
threatened by passage barriers, unscreened irrigation systems, impaired water quality and
periodic siltation of spawning substrate by glacial outbursts.
Clear Branch bull trout spawn in Clear Branch and Pinnacle Creek. After rearing in
these two natal streams for an unknown time period, most are believed to migrate downstream
to Laurance Lake Reservoir. Clear Branch bull trout have been documented passing over the
dam spillway during high water events (Pribyl et al. 1996) and may provide a recruitment source
for the Hood River local population. Adult bull trout tagged at Powerdale Dam have been
observed at Coe Branch irrigation diversion and in a trap at the base of Clear Branch dam.
These fish may have been attempting to reach spawning areas located upstream of the dam.
However, the success of bull trout migrating downstream via the spillway or the possibility of
successfully navigating through the diversion network has never been determined. Depending
on the water year, the Middle Fork Irrigation District (MFID) may not spill at all, or the timing of
the spill may not coincide with the timing of downstream migration, which is currently unknown
(East Fork Hood River and Middle Fork Hood River Watershed analysis).
Smallmouth bass were discovered in Lake Laurance Reservoir in the 1990s. Creel
surveys have shown that large adult bass are caught occasionally in the reservoir and schools
of bass fry have been seen by district fish biologist (Rod French, ODFW, personal
communication), suggesting that they are spawning successfully. This illegal introduction poses
a potential threat to the Clear Branch bull trout population, but its magnitude is unknown
because the bass population size and degree of interaction between the two species are
unknown. Bull trout and smallmouth bass have significantly different temperature preferences
and tolerances, with bull trout being one of the most sensitive coldwater species and bass being
a warm water species. Lake Laurance, a relatively high-altitude reservoir at 890 m (2,920 feet),
does not provide ideal bass habitat so these two species may have largely non-overlapping
distributions or differing activity periods (Terry Shrader, ODFW warmwater fish biologist,
personal communication). However, based on past reservoir temperature data (Berger et al.
2005), there are periods in the reservoir when there is potential for bull trout and bass
interaction: periods when bull trout are susceptible to bass predation and when juvenile fish
might compete for resources.
Spawning activity of the Hood River local population has been observed in a few
locations within the Middle Fork of Hood River (Figure 1). Although consistent and extensive
spawning areas for this population are not known, some of the locations where juvenile rearing
or potential bull trout redds have been observed include the Middle Fork Hood River and some
of its tributaries: Bear Creek, Compass Creek and Coe Branch (USFWS 2004). However, Coe
Branch, Compass Creek, and the Middle Fork are glacial streams with a high volume of sand
and silt which may compromise spawning success. No bull trout spawning or rearing has been
observed on the East and West Forks of Hood River. The Middle Fork and mainstem Hood
River provide foraging, migration and overwintering habitat.
Hood River bull trout are also known to migrate into the Columbia River. Two bull trout
tagged at Powerdale Dam (RK 7.2 of mainstem Hood River) were recovered near Drano Lake in
Washington State; and one was captured 11 kilometers downstream of the confluence of the
Hood and Columbia Rivers (USFWS 2004). Every year (usually between May and July), adult
bull trout, presumably migrating upstream from the Columbia River, are captured and anchor tagged
at Powerdale Dam. Although some of these tagged fish have been observed upstream
(one in Coe Branch and three below Clear Branch dam), the spawning destination of fluvial
adults within the Hood River basin is largely unknown.
Dispersing juvenile bull trout and migrating adults in this local population are threatened
by flow diversions with inadequate screening and passage facilities. Several structures are
suspected to impede upstream migration or entrain juvenile and adult bull trout into irrigation
works (Pribyl et al. 1996, HRWG 1999). These structures include: the diversion at Clear Branch
Dam (passage and screening), Coe Branch (passage and screening), and the Farmers
Irrigation District diversion (screening) on the mainstem Hood River (HRWG 1999). However,
little research has been conducted to assess the impacts of these structures on migrating bull
Beyond a general knowledge of the distribution of Hood River bull trout and the nature of
anthropogenic factors that potentially restrict their life history and habitat connectivity, little is
known about this recovery unit. Baseline information about adult abundance is lacking for both
local populations, the potential of a source (Clear Branch) and sink (Hood River) relationship
between the two local populations has not been explored, and the migratory life history of adult
fish caught at Powerdale Dam is unknown. The degree to which irrigation and hydropower
diversions hamper connectivity within the Hood River basin is also poorly understood. Migratory
life histories have been viewed as key to species persistence (Rieman and McIntyre 1995;
Dunham and Rieman 1999), and understanding movement patterns and associated habitat
requirements are critical to maintaining those migratory forms (Muhlfeld and Morotz 2005;
Hostettler 2005). Gaining this information is also critical to evaluating bull trout recovery in the
Hood River Subbasin (Coccoli 2004).
The Oregon Department of Fish and Wildlife (ODFW) initiated a study in 2006 to
improve our understanding of the abundance, life history, and potential limiting factors of the bull
trout in this recovery unit. This report describes findings for the first two years of the study
(2006-2007). Specific study objectives for the first two years were:
1. Determine the migratory life history of Hood River bull trout and assess the potential
impacts of flow diversions and two new falls on the Middle Fork Hood River (scoured by
the November 2006 glacial outburst) on bull trout migrations.
2. Determine current distribution of bull trout reproduction and early rearing in historical and
potential bull trout streams in the Hood River Subbasin.
3. Determine the juvenile and adult life history the Clear Branch local population and develop
a statistically reliable and cost-effective protocol for monitoring the abundance of adult
Clear Branch bull trout.
4. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake Reservoir.
- Time Period of Content:
- Geographic Extent: Hood River
- Status: Final
- Use Constraints:
- Format: PDF File
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