Oregon Coast Coho Habitat Monitoring Design
Spatial Design
Temporal Design
Response Design
Inference Design
Evaluation Thresholds
References Methods Metadata
Spatial Design
The design is described in detail in Stevens (2002). The sampling is targeted at two spatial
scales: A GIS coverage of all anadromous fish distribution was used as a frame for inference to
Monitoring Areas. A GIS coverage of the available spawning and rearing habitat for coho
salmon was used to make inference for Populations. The coverages were based on USGS
1:25,000 topographic maps, modified by ODFW to correspond to the target population of
streams for each population. Data from the population-scale surveys (which fulfill Measurable
Criteria 6 in the State of Oregon Conservation Plan for the Oregon Coast Coho ESU) are
reported in the Summary and Explorer tools on this site. Additional data may be available via
download. Dependent populations and some independent populations are grouped together
spatially and sampled in aggregate to form 20 population sample frames, referred to as
population blocks. Generalized Random Tessellation Stratified designs (GRTS) achieve a
spatially-balanced random point distribution (Stevens, 1997; Stevens & Olsen, 1999; Stevens &
Olsen, 2003; Stevens and Olsen, 2004) and this approach was used.
Population units within each sampling block. A “+” indicates addition of adjacent dependent
populations to small independent population.
Sampling block
Population block
Type
Northern Coast
Necanicum +
Independent & Dependent
Nehalem
Independent
Tillamook
Independent
Nestucca
Independent
Neskowin +
Dependent
Central Coast
Salmon River, Devils Lake Independent & Dependent
Siletz
Independent
Yaquina
Independent
Alsea
Independent
Beaver Creek +
Independent & Dependent
Siuslaw & Umpqua Siuslaw
Independent
Lower Umpqua
Independent
Main Umpqua
Independent
North Umpqua
Independent
South Umpqua
Independent
South Central
Yachats +
Dependent
Lakes basins
Independent
Coos
Independent
Coquille
Independent
Sixes, Floras
Independent & Dependent
Temporal Design
Population blocks will be sampled once every 5 years starting in 2006, so that every population
will have been sampled by 2011. Sampling order will be randomly determined for each 5 year
period. To balance trend and status detection, 40% of sites within a population block will be
revisited every 5 years and 60% will be visited only once. Following the first 5 years of
population scale habitat surveys, sample size in each population block will be adjusted based
on sensitivity analyses of the habitat variables.
Response Design
Selected sites are visited during winter base flows (December - mid-March) and revisited during
summer low flow period (mid-June - September). Surveyors collect information on channel
size, flow, substrate composition, large wood, habitat complexity, and riparian characteristics.
For a full description of the field methods used to conduct the stream habitat surveys click here.
The Habitat Limiting Factors Model (HLFM version 7.0) is used to estimate the capacity of
aquatic habitat to support juvenile coho during the winter. The background, scientific basis, and
application of the HLFM are described in Reeves et al (1989), Nickelson et al. (1992),
Nickelson (1998), and Nickelson and Lawson (1998). Since the publications in 1998, two major
adjustments have been made to the model. The first (version 6) reduced the potential density
that large streams could support. The second modification (version 7) recognized the role that
large complex jams could play in providing refugia for juvenile coho during the winter,
effectively increasing the carrying capacity of a stream. The two adjustments to the model were
based on data collected during the studies referenced above, and ongoing studies within the
coastal coho ESU (e.g. Jepsen and Leader 2008) (T. Nickelson, personal communication).
Inference Design
The recommended estimator is the Horvitz-Thompson or π-estimator. Briefly, the estimator
weights the observation collected at si by the reciprocal of the inclusion density function π(si).
Annual status estimates are obtained from all sites visited in that year. The design selects
points on streams. Suppose point si falls on a stream segment with length li. The observation
collected represents an aggregate over the entire length of the segment. Thus, if the
observation is spawner count, then the entire segment is examined for spawners, and all
spawners in the segment are counted. Let yi be the aggregated observation. Then an estimator
of the total number of spawners over the entire stream network is
where n is the number of samples. Moreover, within an assessment unit, π(s) is constant, so,
letting
, the estimator becomes
.
Refer to epa.gov/nheerl/arm for R scripts (spsurvey library; function CDF.compute) to calculate
cumulative distribution functions, population estimates and confidence intervals.
An error estimate of the miles of high quality habitat in each population unit is based on the
95% confidence interval (C.I.) of the cumulative distribution function (cdf) for winter parr. The
point estimate of high quality miles and 95% C.I. is estimated at a value of 1850 parr/km on the
CDF.
Evaluation Thresholds
Goals for the amount of high quality habitat in each non-lake independent coho population in
the Oregon Coast Coho ESU.
References
Firman, J.C., and S.E. Jacobs. 2001. A survey design for integrated monitoring of salmonids. In Nishida,
T., P. J. Kailola and C. E. Hollingworth editors. First International Symposium on GIS in Fishery
Science.
Lawson, P.W., E.P. Bjorkstedt, M.W. Chilcote, C.W. Huntington, J.S. Mills, K.M.S. Moore, T.E.
Nickelson, G.H. Reeves, H.A. Stout, T.C. Wainwright, and L.A. Weitkamp. 2007. Identification
of historical populations of Coho salmon (Oncorhynchus kisutch) in the Oregon coast
evolutionarily significant unit. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-79, 129
p.
Oregon Coastal Restoration Initiative (OCSRI). 1997. The Oregon Plan: Oregon's Coastal Restoration
Initiative. Salem, Oregon.
Oregon Department of Fish and Wildlife. 2007. State of Oregon Conservation Plan for the Oregon Coast
Coho Evolutionarily Significant Unit, Appendix 2. Oregon Department of Fish and Wildlife,
Salem, Oregon.
Rodgers, J.D., K.K. Jones, A.G. Talabere, C.H. Stein, and E.H. Gilbert. 2005. Oregon Coast Coho
Habitat Assessment, 1998-2003. OPSW-ODFW-2005-5, Oregon Department of Fish and
Wildlife, Salem.
Stevens, D.L. 2002. Sampling design and statistical analysis methods for integrated biological and
physical monitoring of Oregon streams. OPSW-ODFW-2002-07, Oregon Department of Fish
and Wildlife, Portland, Oregon.
Thom, B. A., K. K. Jones, and C. S. Stein. 1998. An analysis of historic, current, and desired conditions
for streams in western Oregon. Section IV-ODFW pages 33-56 In The Oregon Plan for Salmon
and Watersheds 1998 Annual Report. (http://www.oregon-plan.org)
Wainwright, T. C., M. W. Chilcote, P. W. Lawson, T. Nickelson, C. W. Huntington, J. S. Mills, K. M. S.
Moore, G. H. Reeves, H. A. Stout, and L. A. Weitkamp. 2006. Biological recovery criteria for the
Oregon Coast coho salmon evolutionarily significant unit. Draft Report, January 2006.
(Available from T. C. Wainwright, NWFSC, Fish Ecology Division, Newport Research Station,
Newport, OR.)