Limiting Factors



Columbia Estuary Province

Grays Subbasin 362

CHUM
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Artificial Propogation Straying Adult spawners Large numbers of stray chum spawning with indigenous populations pose serious genetic risks.
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 Diking Adults Agricultural practices have reduced floodplain function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Adults Agricultural practices have denuded riparian areas in the lower river.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Eggs, fry, adults Habitat diversity has decreased in the lower river because of artificially confined channels, loss of LWD, and denuded riparian areas.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization; Riparian Degradation Eggs Increased sediment is a factor in the lower river.
Water Quality Temperature -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation Eggs Increased water temperature is a factor in the lower river.
Water Quantity Increased Water Quantity -- Agricultural Practices; Forest Management Water: Runoff Coefficient Variation Fry High peak flows originate from upstream sources.
COASTAL CUTTHROAT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices Diking Juveniles, adults Agricultural practices have reduced floodplain function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Juveniles, adults Denuded riparian conditions lead to increased sediment and temperature, and lack of LWD.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Juveniles, adults Many reaches have been impacted by decreased habitat diversity.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization; Riparian Degradation Juveniles, adults Increased sediment is a problem in many reaches.
Water Quality Temperature -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles, adults Denuded riparian conditions lead to increased temperature.
Water Quantity Decreased Water Quantity; Increased Water Quantity -- Agricultural Practices; Forest Management; Urbanization Water: Runoff Coefficient Variation Juveniles, adults Peak flows have been exacerbated by land use and roads.
COHO
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Food Competition -- Artificial Propogation Intraspecific Interaction Summer parr Hatchery releases lead to competition with naturally produced juveniles.
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 Diking Juveniles Agricultural practices have reduced floodplain function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Juveniles Agricultural practices have denuded riparian areas in the lower river.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Juveniles Habitat diversity has decreased in the lower river because of artificially confined channels, loss of LWD, and denuded riparian areas.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Coho are subject to both ocean and freshwater harvest.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Summer parr Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization; Riparian Degradation Eggs, summer parr Increased sediment is a problem in many reaches.
Water Quality Temperature -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation Eggs, summer parr Increased water temperature is a factor in the lower river.
Water Quantity Increased Water Quantity -- Agricultural Practices; Forest Management Water: Runoff Coefficient Variation Juveniles High peak flows originate from upstream sources.
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.
Habitat Quantity and Quality Morphological Changes Freshwater-Floodplain Agricultural Practices Diking Adults Agricultural practices have reduced floodplain function.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices Diking; Filling; Riparian Degradation Adults Agricultural practices have denuded riparian areas in the lower river.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation Eggs, fry, adults Habitat diversity has decreased in the lower river because of artificially confined channels, loss of LWD, and denuded riparian areas.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Fall Chinook are subject to both ocean and freshwater harvest.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization; Riparian Degradation Eggs, adults Increased sediment is a problem in many reaches.
Water Quality Temperature -- Agricultural Practices; Forest Management; Urbanization Riparian Degradation Eggs, adults Increased water temperature is a factor in the lower river.
Water Quantity Increased Water Quantity -- Agricultural Practices; Forest Management Water: Runoff Coefficient Variation Fry High peak flows originate from upstream sources.
WINTER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Biological Viability Criteria Diversity -- Artificial Propogation Straying Adults Large numbers of stray steelhead spawning with indigenous populations pose serious genetic risks.
Food Competition -- Artificial Propogation Intraspecific Interaction Summer parr Hatchery releases lead to competition with naturally produced juveniles.
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 Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles Key habitat has been impacted by sedimentation and loss of LWD.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Forest Management; Agricultural Practices Diking; Filling; Riparian Degradation Juveniles Decreased channel stability is caused by the poor condition of riparian forests.
Instantaneous Mortality Predation -- Fishery Management Species Introduction Juveniles Non-native species introductions have lead to community shifts and predation issues.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Impervious Surfaces (Road Density); Sediment: Bank Destabilization; Sedimet: Upland Disturbance; Riparian Degradation All Key habitat has been impacted by sedimentation. Upper subbasin reaches suffer from increased sediment originating from timber harvest, roads, and naturally unstable soils.
Water Quantity Increased Water Quantity -- Agricultural Practices; Urbanization Impervious Surfaces (Road Density); Water: Runoff Coefficient Variation Summer parr High road densities in the South Fork watershed exacerbate peak flows.