The Rapid Bioassessment (RBA) project provides data on
distribution and abundance of juvenile coho, steelhead
and cutthroat in MidCoast basins. The survey involves
snorkeling every 5th pool along the surveyed stream reach
and recording counts of juvenile fish observed. GIS coverages
of RBA data were obtained from the Siuslaw National Forest
office. We used GIS to intersect these coverages with
the 6th field coverage to produce the layers provided
in this assessment. As requested by the MCWC Tech Team,
we summarized two parameters from the Rapid Bioassessment
data:
coho per sq m, and
pool complexity.
Pool complexity is a visual estimate based on percent
of the pool surface area that has cover from wood, large
substrate, undercut banks, and overhanging vegetation.
Values for pool complexity can range from 1 to 5: 1 =
0% cover, 2 = 1-25% cover, 3 = 26-50% cover, 4 = 51-75%
cover, and 5 = >75% cover.
We averaged the 1998 and 1999 values of
coho
per sq m and
pool complexity
for each 6th field in a
summary
layer. We color-coded the 6th fields for coho density
and pool complexity. Average values were weighted by the
number of pools snorkeled in each year to normalize results.
We also summed the
number of pools
for each 6th field to indicate the extent of RBA data.
The 6th field rankings show which subbasins
have the highest average coho density and pool complexity.
When interpreting a 6th field's ranking, note the number
of pools snorkeled in that 6th field. The average coho density
or pool complexity for a 6th field may not be representative
of that entire 6th field if only a few of its pools were
snorkeled.
Please address questions or comments
to:
Dr. Ralph Garono
Principal Investigator
Earth Design Consultants, Inc.
rgarono@earthdesign.com
Laura Brophy
Principal Investigator
Green Point Consulting
brophyl@peak.org |
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