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Pygmy whitefish benefit from restoration efforts that improve stream habitat in the CRMW upstream of Chester Morse Lake. These actions include removing human-caused barriers to pygmy whitefish movement, decommissioning many forest roads that deliver sediment to streams, improving maintenance of other roads to reduce fine sediment inputs, and adding large woody debris (LWD) to enhance instream habitat.
Measuring Success for Protecting Watershed Habitats
We document all our efforts in preventing or containing toxic spills, in preventing and suppressing fire, and in the amount of invasive plants controlled or removed.
View more information on habitat protection metrics.
Measuring Success for Aquatic and Riparian Habitat Restoration
We measure the additional miles of stream accessible to bull trout as a result of removing artificial fish passage barriers, amount of sediment reduction in streams as a result of stream bank stabilization, and number and location of LWD replacement projects within and adjacent to streams that flow into Chester Morse Lake. Bank stabilization at road crossings has been implemented at the Rex River, which has important pygmy whitefish spawning habitat.
See aquatic and riparian habitat restoration metrics.
Measuring Success for Road Decommissioning and Improvements
We document the amount and location of roads that are decommissioned or improved, and estimate the reduction in the amount of sediment delivered to streams that flow into Chester Morse Lake.
See road decommissioning metrics.
Annual Pygmy Whitefish Spawning Surveys
The status of pygmy whitefish in the watershed was monitored by conducting annual spawning surveys from 2001 to 2011. Spawning surveys documented the approximate number of spawning fish, as well as their temporal and spatial distribution in the upper Cedar River and Rex River.
View pygmy whitefish spawning metrics.
View Bull Trout and Pygmy Whitefish Spawning Survey Protocol (pdf).
Pygmy Whitefish Mark-Recapture Study
From 2006 to 2011 a study of the spatial and temporal patterns of pygmy whitefish spawning in the Cedar and Rex rivers was conducted using PIT (passive integrated transponder) tags implanted in a total of 3,012 fish. In general the fish spawned in a narrow lineal section of river habitat within a two-week period in late fall. One fish returned five times to spawn and another was detected six years after tagging, demonstrating that pygmy whitefish spawn in multiple years and can live to at least nine years of age.
For more information on the unique characteristics of riverine spawning pygmy whitefish, view the presentation (pdf) at the American Fisheries Society Conference in September 2011. Scientific results of the study can be found in:
Bull Trout, Rainbow Trout and Pygmy Whitefish Acoustic Telemetry Studies
SPU biologists followed the vertical and horizontal movements of bull trout, rainbow trout and pygmy whitefish in Chester Morse Lake. Acoustic tags were surgically implanted in fish and send data, including date and time stamps, to a hydrophone array in the lake.
View Acoustic Telemetry Study Progress Presentation 2007 (pdf).
See slideshow of research on pygmy whitefish.
Pygmy Whitefish Timing to Hatch Study
Very little is known about the early life history of pygmy whitefish. An HCP project was completed that documented the length of time it took for pygmy whitefish eggs to hatch in natural river conditions. In 2012 the results were published in Northwest Science:
Pygmy Whitefish Body Morphology Study
The body width and depth of individual spawning pygmy whitefish was measured during field sampling in order to better understand body morphology of the species. These data help SPU managers consider screening requirements for engineering projects in Chester Morse Lake.
See Pygmy Whitefish Body Morphology Report 2007 (pdf).
University of Washington and SPU scientists are collecting data to create a bioenergetics model (pdf) that will better explain species interactions, dietary needs, and distribution of all fish species in Chester Morse Lake. Several components of the study include: diet analysis, acoustic surveys of Chester Morse Lake to document fish distribution through the year, and food resource availability through the year in the lake.
Chester Morse Lake Temperature Modeling
Portland State University and SPU scientists collected data from 2005 through 2008 to create a temperature model for Chester Morse Lake. The model helps predict how temperature regimes could change through the year at any given depth, based on various management scenarios of the reservoir. The model will help interpret the behavior of bull trout, rainbow trout, and pygmy whitefish observed in the acoustic telemetry study. View the Chester Morse Lake Temperature Modeling Project Description (pdf) and Temperature and Fish Habitat Model of Chester Morse Lake (pdf).