Assessment of Bull Trout Populations in the Yakima
Assessment of Bull Trout Populations in the Yakima River Watershed
Background l Bull trout listed as “threatened” under ESA on June 10, 1998. l Listed for Columbia & Klamath River DPS. l USFWS recognized distinct bull trout populations in the Yakima River sub-basin.
Current Populations l WDFW Salmonid Stock Inventory Report (1998) indicated 9 distinct bull trout populations in the Yakima sub-basin. l Current data suggests a minimum of 13 spawning populations
Current Populations l 7 populations isolated in upper basin reservoirs. l Minimum of 6 fluvial populations in the Yakima River system. l Redd count range: 4 redds for the weakest 233 redds for the healthiest.
Threats l Isolation by dams, water withdrawals, dewatered streams; water quality problems associated with agriculture, forestry, grazing, roads, mining; over harvest, poaching, non-native species, residential and commercial development activities.
Goal l Recover bull trout in the Mid Columbia Recovery Unit. l This proposal was tailored to compliment the NWPPC’s 2000 Fish & Wildlife program, the Yakima Sub-basin Plan and the Mid Columbia Recovery Plan.
Critical Information Gaps l Connections between populations in the fluvial system. l Lack of information in Cle Elum Lake drainage. l Genetic composition. l Movement (migration) patterns. l Adult summer / winter areas.
Critical Information Gaps l Juvenile rearing & downstream distribution. l Identification & quantification of habitat. l Distribution (presence/absence). l Abundance. l Spawning areas (new areas, refine current indexes).
Presence /Absence Surveys l AFS Protocol procedures for detecting bull trout (Peterson et al. 2001). l Backpack electro-fishing in small stream environments (NMFS Guidelines).
Population Abundance l Snorkel l Refine surveys to locate staging areas. or establish spawning index areas. l Extrapolate abundance from redd counts. l Mark-recapture estimates.
Radio Telemetry Studies l Trap post spawned bull trout. l Intercept bulls in main stem areas. l Radio tag. l Monitor migration / movement patterns. l Determine summer/wintering areas, prespawn staging areas & fidelity to spawning tributaries.
Juvenile Distribution Studies l Determine downstream distribution of early rearing juvenile bull trout via snorkeling procedures. l Migrant (smolt) screw traps on larger tributaries to monitor movement.
Habitat Correlations l Measure & correlate habitat & biotic attributes with the occurrence of juvenile bull trout (Dunham et al 2000). l Measure l Apply habitat in spawning areas. to other areas to determine potential spawning and rearing habitat.
Determine Genetic Composition l Collect tissue samples for micro-satellite DNA genetic analysis. l Tissue samples taken in conjunction with other fish handling activities.
Determine Limiting Factors l Data from this study. l Current data. l Historical or archived information. l Literature searches. l Compare life history requirements to measured conditions. l Incorporate limiting factors into existing databases.
Determine & Implement Management Actions l Synthesize data & limiting factors. l Generate management recommendations. l BPA Reports & other publications. l Information to MCRUT & others working to recover bull trout in the Columbia Basin. l Assist MCRUT with bull trout recovery.
Benefits “Columbia Connection” l Data on distribution, abundance, habitat and genetics will contribute to management, restoration and preservation of bull trout in the Columbia Basin. l Augments other assessment and recovery efforts in the Columbia Gorge & in the upper Columbia/Wenatchee system.
Benefits “Columbia Connection” l Consistent with and supports the vision of the NWPPC’s 2000 Columbia River Basin Fish & Wildlife Program, the Yakima Subbasin Plan, and the Mid Columbia Bull Trout Recovery Plan.
Benefits “Columbia Connection” l Objectives designed to facilitate the 2000 Program directives by resolving key uncertainties associated with resident fish losses. l Objectives can be measured and quantified. Information vital for implementing recovery in the Yakima arm of the Columbia basin.
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