By Ev Hoyt
Black Hills Flyfishers Treasurer
When Jack Erickson left for his new job assignment with GFP in Pierre, he handed off the Didymo
ball to Jeff Shearer, who took on Didymo at full speed and appears headed for a score. Jeff has
been involved with Rapid Creek Didymo from the “get-go”, as he was one of the GFP team
members who participated in the early stages of Rapid Creek Didymo research with EPA in 2005.
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Jeff was a member of the Black Hills delegation
attending the international Didymo conference in
Bozeman in May of 2006, which was hosted by
the American Fisheries Society and by Dr. Sarah
Spaulding of EPA and Leah Elwell of FFF. Other
members of the Black Hills delegation included
Jack Erickson of GFP, Steve Hirtzel of
USFS/BHNF, Aaron Larson of SDDENR, and Jim
Hawke and Ev Hoyt of BHFF. Nearly 100 Didymo
scientists from the United States, New Zealand,
British Columbia, Iceland, and the United
Kingdom were in attendance at the symposium to
share their research and information about
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Didymo, the “good algae gone bad.” You will recall that BHFF contributed $3,000 to the conference
organizers so that Dr. Barry Biggs of New Zealand, and Dr. Kelly of the United Kingdom could
attend and present their research papers to the assembly.
Jeff was a also one of the key presenters, as he shared his research from Rapid Creek which
showed the “circumstantial” link between Didymo and the decline in brown trout populations in
Rapid Creek below Pactola Dam, where Didymo is present in nuisance populations. Through his
analysis of the electroshocking population data over several years, Jeff demonstrated that although
the fish population showed substantial numbers of young-of-the year brown trout, there was a near
absence of brown trout in the two to four year age classes. In other words, the baby trout died off in
near-total numbers, probably because Didymo had nearly wiped out the aquatic insects important
to growth and survival of the young trout.
In a somewhat related presentation, Dr. Max Bothwell of British Columbia, shared his research with
stream enrichment projects which he had conducted on streams on Vancouver Island, BC, over a
fifteen year period. There, as the streams had become nutrient poor as a result of the decline in
salmon spawning runs, Didymo had become prevalent. Bothwell’s research showed that as a result
of the addition of phosphorus to those streams in the correct ratio to nitrogen, the steelhead smolt
in the enriched streams grew to nearly twice the size of those in the nutrient-poor streams
dominated by Didymo. As a result, the smolt were in much better condition as they migrated to the
ocean, and as they returned to the streams of Vancouver Island some years later. However,
Bothwell had not documented the effect of the nutrient enrichment project on the resident rainbow
and brown trout.
Jim Hawke and Ev Hoyt participated in the conference to share the effect of Didymo and declining
trout numbers from the perspective of the angling community, indicating that the impact of Didymo
had been disastrous in Rapid Creek.
During the conference, Hawke and Hoyt took the opportunity to discuss the Rapid Creek situation
at length with Dr. Bothwell, and at the conclusion of the conference Bothwell told Hawke, Hoyt and
Shearer that he would conduct an experiment on the Puntledge River in BC to determine the impact
of stream enrichment on the growth of Didymo. Shearer was to be the SDGFP representative in the
experiment, and BHFF offered to provide financial support to the project. Unfortunately, after
Bothwell had designed the experiment, BC Hydro scheduled flushing flows on the Puntledge,
causing Bothwell to abandon his plans for the enrichment project last summer.
Fortunately for BHFF and anglers in the Black Hills, that’s not the end of the story. We’re pleased
that Jeff Shearer now has the ball in his capable hands – working from the research done by
Bothwell in BC streams, and in consultation with Dr. Bothwell, Jeff has designed a stream
enrichment experiment for Rapid Creek in Pactola Basin in 2007. Jeff took the proposal public in a
presentation to interested residents at Johnson Siding in November, and his proposal received the
enthusiastic endorsement from those present. Jeff has now filed an application with DENR for a
permit to conduct the “stream enhancement project” in Pactola Basin throughout 2007. If the
application is contested by anyone, the application will go before the SD Board of Water
Management for hearing on the merits. If the application is contested in the DENR proceeding,
BHFF will file comments in support of the project and appear at the hearing to offer testimony in
support of the project.
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The plan for the stream enhancement project in
Pactola Basin is to enrich the phosphorus-poor
discharge from Pactola Lake by adding a time-
released fertilizer, keeping the critical
phosphorus-to-nitrogen ratio in the desired
range, so that the survival chances for young-of-
year brown trout will be improved – similar to the
Bothwell project in BC. Water chemistry, bug
communities, and the fishery will be closely
monitored during the project in order to document
the changes and results of the enrichment
process.
The enhancement project will impact Rapid Creek
from just below the USGS gaging station in
Pactola Basin to the footbridge near Placerville
Church Camp, about three kilometers
downstream. There is absolutely no danger to
any downstream user of Rapid Creek as the
water quality parameters during the enhancement
project are expected to be similar to those in
Rapid Creek in Rapid City.
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We applaud Jeff Shearer for “taking the bull by the horns” and designing a project for Rapid Creek.
We are not aware of any other Didymo project on the drawing board in the United States. We are
most appreciative of the support which Jeff has received from Dennis Unkenholz, GFP Fisheries
Program Administrator, and senior GFP staff in funding this Didymo research project. During their
December meeting, your BHFF Board authorized $5,000 in support of Jeff’s stream enhancement
project.
Way to go, Jeff! We’ll be interested in your reports concerning the results of your state-of-the-art
stream enhancement project in Pactola Basin. We’re confident that you’re on the right track!
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