Nearshore Habitat Use by Juvenile Chinook Salmon in Lentic ...

120
Chinook/100 m
100
80
60
40
20
sandy beach
steel wall
0
8-April
Survey dates
6-May
FIGURE 23.—Juvenile Chinook salmon abundance (number/100 m shoreline) at the Shuffleton Power
Plant Outflow (steel wall) and an adjacent sandy beach area, south Lake Washington (2003).
Discussion
We surveyed a variety of potential restoration sites in 2003. Because juvenile
Chinook salmon are concentrated in the south end of the lake, restoration projects in that
area would most likely be more beneficial than those in other areas of the lake. The
Shuffleton Power Plant Outflow is much closer to the mouth of the Cedar River than the
other sites and thus would probably be a better site for a restoration project. The habitat
at this site is highly degraded; there is little shallow water habitat or riparian vegetation
due to the steel wall. Both Beer Sheva Park and Rainier Beach Lake Park are relatively
close to the mouth of the Cedar River and good numbers of Chinook salmon appear to be
present and thus these sites would be good restoration sites. Chinook salmon were
abundant at the Beer Sheva Park boat ramps in 2002 and 2003 and therefore, there should
be several juvenile Chinook salmon in the area to use the mouth of Mapes Creek if it is
daylighted. The undeveloped section of Rainier Beach Lake Park appeared to have good
quality habitat due to its small gravel substrate and gentle slope. This site could be
improved, however, with some additional shoreline vegetation (e.g., willows Salix spp.)
to provide overhead cover as well as small woody debris for structural complexity.
Certainly, the marina shoreline could be improved with the removal of the armoring and
replacing it with small substrates and some riparian vegetation on a gentle sloping bank.
Seward Park has been surveyed for the past five years (2000 by USACOE and
2001-2004 by USFWS) and during that period the nearshore abundance of juvenile
Chinook salmon has been relatively low at all six sites. Even at the best location in
Seward Park (supplemental site S-1 in the southwest corner of other park), the abundance
of Chinook salmon in 2003 was 1.4 to 6 times lower than the undeveloped restoration
transect at the Rainier Beach Lake Park. Restoration projects in Seward Park will have a
positive effect on Chinook salmon habitat but the effect will most likely be small.
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