1 / 28

Coldwater Streams Chapter 18

Coldwater Streams Chapter 18. Coldwater Streams. Game fish - predominantly salmonids Salmon, trout. Coldwater Streams. Anadromous type 1 - use streams only for spawning, move out immediately after emergence Chum, pink, sockeye. Coldwater Streams.

aseyler
Download Presentation

Coldwater Streams Chapter 18

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Coldwater StreamsChapter 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 0.6-6.0% • 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

  14. Salmonid Characteristics • Growth • Suboptimal temperature • Limited food and space • Initial year - 100-150 mm, decline in following years to 20-40 mm/year

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

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

  17. Salmonid Characteristics • Density-independent factors • Predation • Birds • Mammals • Fish

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

  19. Salmonid Characteristics • Higher mortality among males • Longevity - 4-5 years

  20. Angling Mortality

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

  22. Salmonid Characteristics • Redd - spawning bed • Water velocity • Depth • Substrate

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

  24. 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

  25. Annual Production • Similar in single- or mixed-species streams • Softwater streams - 15-50 kg/hectare • Hardwater streams - 100 kg/hectare

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

More Related