Skeena Steelhead Conservation Units

Summary

Purpose:  Steelhead Conservation Units were defined for the Skeena River using methodology consistent with the Wild Salmon Policy. The process combined  habitat , life history and molecular genetics knowledge

Habitat:    To maintain adaptive genetic diversity it is necessary to maintain a diversity of habitats. The diverse watersheds of the Skeena were grouped into terrestrial habitat types consistent with provincial land use planning procedures. The approach also has potential for assisting in achieving the habitat goals of the Wild Salmon Policy.

Aquatic Classification:    Skeena watersheds were classified into Regional hydrology groups. These watershed types, along with gradient, temperature,  nutrients, migration difficulty and distance from the ocean are thought to be the physical factors most relevant to the development of critical adaptive traits for salmonids

Life History   Steelhead have the most diverse life history of any of the salmonids. Their absolute dependency on a long period of freshwater rearing (generally 3-5 years) combined with a variable period in salt water (1-3 years with the option of repeat spawning) results in a complex variety of life history strategies. Previous studies (Cox-Rogers 1985) demonstrated clear, genetically-based life history differences among the Zymoetz, Bulkely/Morice, Kispiox, Babine and Sustut populations. This was a small subset of the total number of Skeena steelhead populations but together they accounted for a significant proportion of production and provided representation from lower, middle and upper tributaries.

Molecular Genetics. Molecular genetics provided new insights into relatedness and the degree of reproductive isolation among steelhead populations. Analysis of Skeena samples using methods consistent with those in the Wild Salmon Policy resulted in the definition of an absolute minimum of 6 main groups within the existing Freshwater Adaptive Zones as follows :(note that all populations were not included in the analysis due to sampling limitations): Lower Skeena (Zymoetz, Lakelse, KitsumKalum); the Middle Skeena subdivided into 3 groups; (Babine), (Kitsequecla/Suskwa) and (Bulkley, Morice/ Kitseguecla/Toboggan/Kispiox). The Upper Skeena subdivided into two groups   (Mosque/Kluatantan/Lower Sustut) and (Upper Sustut).

Final Conservation Units: Aggregating and analyzing the life history, habitat and molecular genetics data resulted in 11 steelhead Conservation Units.

Conclusion: The analysis provides support for the characterization of steelhead as a species rich in genetic variation as expressed by the complexity of life history types present and utilization of diverse habitat types. It again confirms the Skeena River as one of the few remaining naturally productive and diverse salmonid systems in the world

download file
http://skeenawatershedinitiative.com/libraryfiles/lib979.pdf
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author
Tautz, A.F.; Pollard, S.; Hooton, R.S.; Ptolemy, R.A.; Taylor, E.B.
publication year
2011
document type
report
subjects
conservation units
location
Skeena River Watershed
related species
steelhead