Limiting Factors



Columbia Plateau Province

Columbia Lower Middle Subbasin

COHO
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Coho are subject to both ocean and freshwater harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass three or four mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian Juveniles Juvenile salmonids are being harvested by birds and fish predators at rates higher than prior to hydro-development.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals Juveniles Contaminant inputs from upstream land-use activities are often trapped in the reservoirs behind the dams.
Water Quality Temperature -- Water Management Water: Temperature and Gas alteration Juveniles High temperatures during upstream migration of salmonids limit productivity.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal, Channelization, Management Juveniles, adults Peak flows and frequent water level fluctuations have a deleterious and sometimes fatal effect on juvenile salmoinds. Fluctuations in flows can delay adult salmonid migrations.
FALL CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Fall Chinook are subject to both ocean and freshwater harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass three or four mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian Juveniles Juvenile salmonids are being harvested by birds and fish predators at rates higher than prior to hydro-development.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals Juveniles Contaminant inputs from upstream land-use activities are often trapped in the reservoirs behind the dams.
Water Quality Temperature -- Water Management Water: Temperature and Gas alteration Juveniles High temperatures during upstream migration of salmonids limit productivity.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal, Channelization, Management Juveniles, adults Peak flows and frequent water level fluctuations have a deleterious and sometimes fatal effect on juvenile salmoinds. Fluctuations in flows can delay adult salmonid migrations.
SUMMER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices; Urbanization Diking; Impervious Surfaces (Road Density); Riparian Degradation Juveniles Rock Creek Road and other structures in the Rock Creek watershed have altered the floodplain and confined the creek and tributaries.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices Diking; Filling; Wood/Structure Removal Juveniles Lack of habitat diversity (pools with cover) and lack of large woody debris in Rock Creek and its tributaries limit productivity.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass three or four mainstem dams during migration.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian Juveniles Juvenile salmonids are being harvested by birds and fish predators at rates higher than prior to hydro-development.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals Juveniles Contaminant inputs from upstream land-use activities are often trapped in the reservoirs behind the dams. Fluctuations in toxics have reduced native aquatic vegetation and fauna in lower sections of Rock Creek.
Water Quality Temperature -- Water Management Water: Temperature and Gas alteration Juveniles High temperatures during upstream migration of salmonids limit productivity. In Rock Creek, greater summer maxima and winter minima temperatures affect fish life histories. Fluctuations in water quality parameters (i.e., temperature, dissolved oxygen, and nutrients) have reduced native aquatic vegetation and fauna in lower sections of Rock Creek.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal, Channelization, Management Juveniles, adults Peak flows and frequent water level fluctuations have a deleterious and sometimes fatal effect on juvenile salmoinds. Fluctuations in flows can delay adult salmonid migrations.
WHITE STURGEON
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Dam or Hydropower Facility Management Migration Impediments Adults White sturgeon are unable to use existing fish ladders
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Dam or Hydropower Facility Management Water: Storage or Withdrawal Adult spawners Mainstem spawning habitat has been lost due to inundation by mainstem dams.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Sport and commercial harvest limit adult white sturgeon abundance.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Adults Operation of the hydro-facilities has disrupted the historical migration patterns of white sturgeon and resulted in fragmentation of habitat and populations.
Toxic Contaminants Water; Biota -- Pollution and Contamination Pollution: Biological Wastes, Fertilizer, & Pharmaceuticals Eggs, adults Sedimentation/contaminants may reduce adhesiveness of eggs. Contaminants also may affect survival, growth, and reproductive potential of white sturgeon adults.
Water Quality Temperature -- Water Management Water: Temperature and Gas alteration Eggs Elevated water temperature affects white sturgeon eggs.
Water Quantity Altered Flow Timing -- Dam or Hydropower Facility Management Water: Storage or Withdrawal, Channelization, Management Juveniles Lack of multi-day uniformality in flow, turbulence, and turbidity result in white sturgeon year-class failures.