Extent of Anadromy in Bull Trout and Implications for Conservation of a Threatened Species

Brenkman, Samuel J.; Corbett, Stephen C.

doi:10.1577/m04-132.1

Cited by 43 publications

(42 citation statements)

References 14 publications

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“…In this study, the spatial extent of radio‐tagged fish annually increased after dam removal, and temporal movements were similar to those of anadromous Bull Trout in the nearby Hoh River, Washington (Brenkman and Corbett ). Elwha River Bull Trout typically moved upriver from June through September of each year and returned to the lower river and estuary; some fish made consecutive‐year spawning migrations.…”

Section: Discussionsupporting

confidence: 60%

Rapid Recolonization and Life History Responses of Bull Trout Following Dam Removal in Washington's Elwha River

Brenkman

Peters

Tabor

et al. 2019

N American J Fish Manag

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Connected river systems confer advantages upon migratory salmonids by facilitating greater life history expression and, ultimately, population persistence. In Washington's Elwha River, two impassable, century‐old hydroelectric dams were removed in the world's largest dam removal project. Dam removal restored access to 130 km of habitat and reconnected headwater, estuarine, and marine areas. We used multi‐year radiotelemetry data to characterize migratory patterns of federally threatened Bull Trout Salvelinus confluentus after dam removal. Bull Trout rapidly responded to barrier removal and were the first among the Pacific salmonids to move into the newly accessible headwaters. Spatial extent and mean distance traveled upriver increased annually, and adults reached the headwaters (64 km) within 3 years of dam removal. Telemetry data revealed that Bull Trout migrated between the river and its estuary (up to 168 km), and spawning migrations occurred in consecutive years. Relocations of Bull Trout in the tidal zone and the presence of bright, silvery colored adults were indicative of marine residence. Length at age of Bull Trout significantly increased after dam removal, and fish captured before and after dam removal were larger at similar ages in comparison with migratory populations throughout their range. We described the diet of Bull Trout captured in the river and estuary after dam removal. Bull Trout primarily consumed Pacific salmonids Oncorhynchus spp., Threespine Sticklebacks Gasterosteus aculeatus, and sculpins Cottus spp., and the prevalence of sculpins in their diet decreased from the estuary to upstream areas. As the length of Bull Trout increased, they progressively consumed larger prey items. In this historic dam removal project, Bull Trout were early and rapid recolonizers and displayed migrations throughout the reconnected river and its estuary. This study is among the first to evaluate Bull Trout responses to dam removal and establishes a baseline to assess future recovery of this threatened species in the Elwha River.

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Section: Discussionsupporting

confidence: 60%

Rapid Recolonization and Life History Responses of Bull Trout Following Dam Removal in Washington's Elwha River

Brenkman

Peters

Tabor

et al. 2019

N American J Fish Manag

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“…Thus, there may be important age or life-stage dependent patterns of migration, with variability in migratory behavior more complex than classic definitions based only on origins or destinations. In many cases, the actual "destination" of migration is not clear, as fish may use multiple habitats during migration (e.g., Brenkman and Corbett 2005), or change destinations among years (O'Brien 2001).…”

Section: Movementmentioning

confidence: 99%

Evolution, Ecology, and Conservation of Dolly Varden, White spotted Char, and Bull Trout

et al. 2008

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We review the ecology and conservation of three lesser‐known chars (genus Salvelinus): Dolly Varden (S. malma), white‐spotted char (S. leucomaenis), and bull trout (S. confluentus). Dolly Varden is distributed across the northern Pacific Rim and co‐occurs with bull trout and white‐spotted char at the southern extremes of its range. In contrast, bull trout and white‐spotted char are naturally isolated, with the former restricted to North America and the latter distributed in northeastern Asia. Though the range of Dolly Varden overlaps with the two other chars, it is most closely related to Arctic char (S. alpinus), whereas bull trout and white‐spotted char are sister taxa. Each species exhibits diverse life histories with respect to demographic characteristics, trophic ecology, and movement. This diversity appears to be tied to environmental variability (e.g., temperature, habitat connectivity), resource availability (e.g., food), and species interactions. Increasingly, these interactions involve nonnative species including nonnative salmonines and changes in food webs related to establishment of species such as Mysis shrimp in large lakes. As humans expand into the remote and pristine habitats that support these three chars, we encourage proactive consideration of the lessons learned where chars have already declined and internationally‐based research and conservation.

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“…vegetation classes made up more than 70% of the area used by bull trout. Our results will help managers identify specific nearshore areas that may require further protection to sustain the unique anadromous life history of bull trout.Bull trout Salvelinus confluentus commonly display migratory and nonmigratory life histories in freshwater habitats (Fraley and Shepard 1989;Thiesfeld et al 1996;Brenkman et al 2001Brenkman et al , 2007Brenkman and Corbett 2005;Mogen and Subject editor: Michelle Heupel,…”

mentioning

confidence: 99%

“…Bull trout Salvelinus confluentus commonly display migratory and nonmigratory life histories in freshwater habitats (Fraley and Shepard 1989;Thiesfeld et al 1996;Brenkman et al 2001Brenkman et al , 2007Brenkman and Corbett 2005;Mogen and Subject editor: Michelle Heupel,…”

mentioning

confidence: 99%

Marine Habitat Use by Anadromous Bull Trout from the Skagit River, Washington

et al. 2011

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Acoustic telemetry was used to describe fish positions and marine habitat use by tagged bull trout Salvelinus confluentus from the Skagit River, Washington. In March and April 2006, 20 fish were captured and tagged in the lower Skagit River, while 15 fish from the Swinomish Channel were tagged during May and June. Sixteen fish tagged in 2004 and 2005 were also detected during the study. Fish entered Skagit Bay from March to May and returned to the river from May to August. The saltwater residency for the 13 fish detected during the out‐migration and return migration ranged from 36 to 133 d (mean ± SD, 75 ± 22 d). Most bull trout were detected less than 14 km (8.5 ± 4.4 km) from the Skagit River, and several bay residents used the Swinomish Channel while migrating. The bull trout detected in the bay were associated with the shoreline (distance from shore, 0.32 ± 0.27 km) and occupied shallow‐water habitats (mean water column depth, <4.0 m). The modified‐minimum convex polygons (MMCPs) used to describe the habitats used by 14 bay fish showed that most areas were less than 1,000 ha. The mean length of the shoreline bordering the MMCPs was 2.8 km (range, 0.01–5.7 km) for bay fish and 0.6 km for 2 channel residents. Coastal deposits, low banks, and sediment bluffs were common shoreline classes found within the MMCPs of bay fish, while modified shoreline classes usually included concrete bulkheads and riprap. Mixed fines, mixed coarse sediments, and sand were common substrate classes found within MMCPs; green algae and eelgrass (Zostera sp.) vegetation classes made up more than 70% of the area used by bull trout. Our results will help managers identify specific nearshore areas that may require further protection to sustain the unique anadromous life history of bull trout. Received October 25, 2010; accepted May 5, 2011

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Extent of Anadromy in Bull Trout and Implications for Conservation of a Threatened Species

Cited by 43 publications

References 14 publications

Rapid Recolonization and Life History Responses of Bull Trout Following Dam Removal in Washington's Elwha River

Rapid Recolonization and Life History Responses of Bull Trout Following Dam Removal in Washington's Elwha River

Evolution, Ecology, and Conservation of Dolly Varden, White spotted Char, and Bull Trout

Marine Habitat Use by Anadromous Bull Trout from the Skagit River, Washington

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