"Declines
in steelhead abundance have been caused by sharply reduced ocean survivals combined
with impaired freshwater habitat capability. Wild stocks in most systems will
not recover unless their freshwater productivity can be significantly increased
to compensate for reductions in marine survival", Lill (2002).
A
broad range of restoration activities may be used to increase freshwater productivity
ranging from a single application of slow release fertilizer to a large scale
channel reconstruction and complexing program. The level of intervention is dependant
on several factors including the severity of population decline and the capacity
of a stock to rebuild naturally (stock productivity).
In
order to determine the restoration options available in a particular watershed
it is important to understand the habitat limitations and the specific life history
pattern in a given watershed. The average age at spawning in the Greater Georgia
Basin is four, two years in the freshwater environment and two years in the marine
environment. With the longest freshwater residency of any of the pacific salmonids
(between one and five years) it becomes clear that degradation of the freshwater
environment has the most serious impact on steelhead trout populations.
The
following life cycle diagram depicts the steelheads life history. It should be
noted that the steelhead trout display the most plasticity of any species of pacific
salmonids with life histories ranging from two to eight years, depending on the
stock.