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Use of Stream Habitat Surveys to Predict Rearing Capacity of Juvenile
Steelhead
Steven P. Cramer &
Nicklaus K. Ackerman
S.P. Cramer & Associates, Inc.600 NW Fariss Rd.Gresham, OR 97030www.spcramer.com
Today’s Topics
1. The Unit Characteristic Method: Helping Bridge the Gap in our
Understanding of Habitat and Fish
2. UCM Driving Functions and Justifications
3. Investigating the accuracy of UCMcapacity estimates
Today’s Topics
1. The Unit Characteristic Method: Helping Bridge the Gap in our
Understanding of Habitat and Fish
2. UCM Driving Functions and Justifications
3. Investigating the accuracy of UCMcapacity estimates
The UCM: Helping Bridge the Gap in our Understanding of Habitat and
Fish
Understanding stream capacity is important to fisheries management and conservation.
Stream capacity is related to availability of habitat resources.
The UCM uses relationships between steelhead rearing densities and habitat features, at the life stage that is most limiting to production, to determine a stream’s capacity.
Capacity BottleneckHabitat for summer rearing of parr is
typically limiting
Graph from Ward and Slaney 1993
Today’s Topics
1. The Unit Characteristic Method: Helping Bridge the Gap in our
Understanding of Habitat and Fish
2. UCM Driving Functions and Justifications
3. Investigating the accuracy of UCMcapacity estimates
Functions of the UCM
UnitComposition
Observed Parrdensities by unit
type
RawCapacity
Wood inPools
Boulders inRiffl es
Depth
I nvert.Production
Alkalinity
Turbidity
OverwinterSurvival(Cobble
I nterstices)
SmoltCapacity
Unit Reach Stream
%Fines
Standard Parr Densities• Represent the
capacity of unit types to hold parr.
•Based on observations from fully seeded coastal Oregon streams.
Steelhead
Pool
Glide RapidRiffl
ePoo
lGlide Rapi
dRiffl
e
Parr
/m2
0.00
0.04
0.08
0.12
0.16
0.20 Steelhead(19 Streams)
Cutthroat(30 Streams)
Cover J ohnson et al. 1993
Wood Complexity Rating
1 2 3 4
Parr
/poo
l
2
3
4
5
6
7
8
Wood:In pools and
glides
Boulders:A velocity refuge and
feeding station in riffles
Depth
Depth (m)
0.0 0.4 0.8 1.2 1.6 2.0Pa
rr/m
20.00
0.05
0.10
0.15
0.20
0.25Pools
Riffles
• Steelhead prefer greater depths in pools and riffles because depth is a form of cover.
• Within riffles, usage drops as depths exceed 1 meter because velocities in deep riffles begin to exceed parr preferences.
Food
Eff ects of Turbidity on Stream Production
NTU
0 20 40 60 80 100
% o
f Cle
ar W
ater
Pro
duc
tion
0.0
0.2
0.4
0.6
0.8
1.0
0.1m depth
0.3m depth
0.5m depth
E.
Fk.
W.
Fk.La
ke B
r.
• Riffles produce the drift invertebrates upon which juvenile salmonids feed.
•A stream must be composed of at least 50% riffle to produce enough food for steelhead.
• Turbidity reduces light penetration which in turn reduces primary production.
•Primary production is correlated to invertebrate production which is correlated to fish production.
Fine Sediments in the Substrate
• Fine sediments in the substrate reduce cover by filling in spaces in cobble, and also can reduce drift invertebrate production.
Fish
D
en
sity
% Fines
Graph taken from Bjornn and Reiser (1991)
Excessive Fines
Alkalinity
• Streams in different regions inherently produce different numbers of fish in part due to their geochemical makeup.
• Alkalinity has been shown in the literature to be directly correlated to fish production.
Overwinter Survival• Juvenile steelhead overwinter in the interstices of substrate.• Ample cobble relatively free of fines is crucial to overwinter survival.
Functions of the UCM
UnitComposition
Observed Parrdensities by unit
type
RawCapacity
Wood inPools
Boulders inRiffl es
Depth
I nvert.Production
Alkalinity
Turbidity
OverwinterSurvival(Cobble
I nterstices)
SmoltCapacity
Unit Reach Stream
%Fines
Today’s Topics
1. The Unit Characteristic Method: Helping Bridge the Gap in our Understanding of Habitat and Fish
2. UCM Driving Functions and Justifications
3. Investigating the accuracy of UCMcapacity estimates
Model ValidationCompare model estimates of capacity to
observed production in fully seeded basins.
Oregon
Test BasinsWatershed Area:
26-1,420km2
Anadromous Stream Length:660km
Years of Juvenile Monitoring:5-11
Average Smolt Production:2,100-26,000
Oregon
1991 1993 1995 1997 1999
Parr
(x1000)
0
5
10
15
20
25Tenmile Creek
Little North Fork Wilson River
1998 2000 2002 2004
Sm
olts
(x1000)
0
5
10
15
20
25
1991 1993 1995 1997 1999
Parr
(x1000)
0
2
4
6
8 Cummins Creek
1998 2000 2002 2004
Sm
olts
(x1000)
0
10
20
30
40
50Little Butte Creek
1994 1996 1998 2000 2002 2004
Sm
olts
(x1000)
0
10
20
30
40
50
60
70Hood River Trout Creek
1998 2000 2002 2004
Sm
olts
(x1000)
0
10
20
30
40
50
60
Catherine Creek
1997 1998 1999 2000 2001
Sm
olts
(x1000)
0
5
10
15
20
25
30
35
Catherine Creek not fully seeded
Observed Capacity (x1000)
0 10 20 30 40 50
UCM
Cap
acit
y Est
imat
e (
x1000)
0
10
20
30
40
50
1:1 (Obs = Exp)
Regression
Conclusions1. Model functions reflect relationships
known to exist between steelhead production and habitat.
2. The model incorporates data from standard habitat surveys. Subjectivity is minimized, data are widely available, and model simulations can be done quickly.
3. Testing of UCM predicted capacities indicates model results are typically within +/- 35% of observed capacity.
4. Among the test basins, the model tended to underestimate capacity in smaller basins, and overestimate in larger basins. We will add a channel width variable to account for this.
Additional Uses of UCM1. The UCM may be used to estimate
changes in capacity that result from habitat alterations.
2. The UCM can be used to examine how changes in low flow affect stream capacity. This use is soon to be tested and published.
3. The UCM may be used for other species. A spring Chinook model has been developed and applied, but has not yet been validated.