1. Coldwater Streams Chapter 18

2. Coldwater Streams
Game fish - predominantly salmonids
Salmon, trout

3. Coldwater Streams
Anadromous type 1 - use streams only for spawning, move out immediately after emergence
Chum, pink, sockeye

4. Coldwater Streams
Anadromous type 2 - spend 1 or more years in stream before leaving
Chinook, coho, Atlantic salmon
Anadromous trout (some races of rainbow, cutthroat, brown, brook)

5. Coldwater Streams Residents - spend entire life in stream
Bull, rainbow, cutthroat, brown, brook
Brown is only species not native to North America

6. Coldwater Streams - sustain spawning and rearing
Physical conditions
Water temperature <22°C
Dissolved oxygen >8 ppm
Stream size - greatest abundance, diversity in 4th-5th order streams
Stream gradient - best %
Hydrograph -variable

7. Other Fish Species Low diversity in west, higher diversity in east
Cyprinids - minnows - Notropis

8. Other Fish Species
Cyprinids - dace
Rhinichthys, Phoxinus

9. Other Fish Species
Cyprinids - chubs - Semotilus

10. Other Fish Species
Catostomids - suckers - Catostomus

11. Other Fish Species
Cottids - sculpins - Cottus

12. Other Fish Species
Darters - Etheostoma

13. Salmonid Characteristics
Territoriality
Agonistic behavior
Dominance hierarchy
Focal points
Probability of use curves

16. Salmonid Characteristics
Growth
Suboptimal temperature
Limited food and space
Initial year mm, decline in following years to mm/year

17. Salmonid Characteristics
Mortality - 50% or more annually
Density-dependent factors
Intraspecific competition - starvation

18. Salmonid Characteristics
Density-independent factors
Spring floods
High summer temperatures

19. Salmonid Characteristics
Density-independent factors
Predation
Birds
Mammals
Fish

20. Salmonid Characteristics
Density-independent factors
Overwinter mortality
Starvation
Predation - low
Physical injury - ice

21. Salmonid Characteristics
Higher mortality among males
Longevity years

22. Angling Mortality

23. Salmonid Characteristics
Reproduction
Sexual maturity
Age or size
Fall spawners
Brown, brook
Spring spawners
Rainbow, cutthroat

24. Salmonid Characteristics
Redd - spawning bed
Water velocity
Depth
Substrate

25. Salmonid Characteristics
Eggs develop in gravel until hatching
Emergence - early or late spring

26. Stream Species Composition
Most streams influenced by past introductions
Brook, brown, rainbow
Competition for resources
Brook trout replace cutthroat trout
Brown, rainbow replace brook trout

27. Annual Production Similar in single- or mixed-species streams
Softwater streams kg/hectare
Hardwater streams kg/hectare

28. Management Historical Introductions followed by maintenance stocking
Current
Habitat restoration, management
Restoring species
Special regulations