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Salmon Recovery Aided by Water Flow Changes

Posted on behalf of Ben Sherman <Sherman@nasw.org>

Editor's Note: Ensuring the survival of migratory fish that spawn up stream
is an issue of increasing concern. Yesterday (3/16) NOAA’s
National Marine Fisheries Service announced that nine species of salmon in
the Puget Sound watershed would be listed as endangered or
threatened.  Dam operations, combining with heavy fishing pressure, are
making such fish increasingly candidates for listing on
threatened or endangered lists.  While such listings of endangered salmon
runs in the Pacific Northwest have generated a great deal of
attention, the issue is also being faced in the Great Lakes region. NOAA Sea
Grant research is showing that changes in water flow
management and dam water draw operations could provide significant payoffs.

Fish respond to natural water flow in Manistee River; economic benefits
could follow


Edward S. Rutherford, Assistant Research Scientist, Michigan Sea Grant,
University of Michigan
School of Natural Resources and Environment, (O) 734- 663-3554, E-Mail:

Michael Moore, Associate Professor of Natural Resource and Environmental
Michigan Sea Grant, University of Michigan School of Natural Resources and
(O) 734- 647-4337, E-mail: micmoore@umich.edu

Joyce Jakubiak, Editor, Michigan Sea Grant, University of Michigan,
(O) 734- 647-0766, E-Mail: jjakub@engin.umich.edu

Ben Sherman, National Sea Grant Media Relations (O) 202-662-7095, E-Mail:

ANN ARBOR, MI. For 80 years, water flow in western Michigan's Manistee River
fluctuated dramatically each day ? ranging from 10-year
floods to drought conditions. The variation was caused by hydropower dam
operations known as peak flow management, a practice that
permits the periodic release of large amounts of water. Studies have shown
that such erratic flows can cause aquatic organisms to
alternately become stranded or swept downstream, negatively impacting the
fish that rely on them for food.

On the Manistee, a major Lake Michigan tributary, relief came in 1989. Peak
flow management was abandoned in favor of a less disruptive
practice known as run-of-river flow management. Water was allowed to flow
naturally through the Tippy and Hodenpyl dams as a result of
terms specified in new hydropower licenses. Today, a decade later, the
change is beginning to pay off. Researchers at the University of
Michigan and Michigan State University, funded in part by NOAA’s Michigan
Sea Grant Program, have found that survival of young chinook
salmon in the Manistee has increased dramatically since the late 1980s in
response to a stable water flow.

"Natural reproduction is incredible now," says Sea Grant and University of
Michigan fisheries biologist Ed Rutherford. "It's gone from
virtually nothing to approximately 700,000 smolts annually."

Still, the switch to run-of-river flows hasn't solved everything. The
researchers found that although steelhead reproduction has also
increased, the fish had a lower survival rate than that of young chinook.
Rutherford suspects warm water temperatures may be the reason.
Steelhead spawn and rear in the tailwater of dams, he explains, where summer
water temperatures may be too warm. Many top-draw
dams pull the warmer surface water from above the dam, which then flows
downstream. Because steelheads remain in the stream longer
than salmon, Rutherford suspects they may be affected to a greater degree by
warm water temperatures.

Using electroshocking sampling techniques, Rutherford and colleagues
measured the abundance and diversity of fish in the Manistee over
a two-year period. They also used smolt traps to monitor the smolt run and
examined the scales and vertebra of adult fish to distinguish
wild salmon from those reared in hatcheries. (Salmon reared in hatcheries
make up the majority of the salmon caught in Lake Michigan.)
The researchers estimate that the greater numbers of chinook and steelhead
wild smolts surviving in the Manistee represent an 8.6 and
6.4 percent increase, respectively, in potential harvest available to
recreational anglers, as compared to the harvest during peak flow
regimes in the late 1980s.

The Bottom Line

The increase in chinook and steelhead is crucial information for the next
phase of the project to be completed this year. University of
Michigan economist Michael Moore, and colleagues Michigan State University
agricultural economists Frank Lupi and John Hoehn, will
use a state-of-the-art economic model of recreational fishing in Michigan to
translate the improved ecological changes into the dollars and
cents of economic benefits.

They already know one thing: sportfishing is big business. Chinook and
steelhead are two of five species of fish that make up the
salmonids group. Spending associated with recreational fishing for salmonids
in the Great Lakes is estimated to contribute $1 billion per
year to the economy, according to a Great Lakes Fisheries Commission Special
Economic Report. However, estimating the economic
benefit of improvements to the sport fishery can be tricky.

For instance, in the process of relicensing hydropower dams, the Federal
Energy Regulatory Commission (FERC) was required in 1986 to
consider the benefits of fish and wildlife protection, recreational
opportunities, and preservation of environmental quality. The problem,
explains Moore, is that FERC's method of analysis has historically
characterized costs and benefits only in terms of profits and losses to
the companies that own the dams. As part of the research, Moore and
colleagues reviewed FERC's analytical procedures.

"One of the things we found," says Moore, "is that FERC collects very little
information on benefits of improved ecosystem function and
recreational opportunities. They do an unbalanced analysis."

Incorporating comprehensive data on costs and benefits can have tangible
effects. For example, explained Moore, each hydropower
license contains a series of operating conditions. Specific operational
changes such as adding fish ladders or changing to run-of-river flow
scan be required if potential benefits are first recognized and quantified.
On the Manistee, new data on steelhead raises the question of
altering top-draw dam operations to bottom-draw to provide steelhead with
cooler water. In essence, Moore said, a full accounting of the
economic benefits might provide a basis for recommending operational

The economic model will balance these benefits against the costs of
run-of-river flows, which are measured in terms of lost hydropower
revenues from the change in flow management.

In the coming years, the economic approach may be relevant to more than just
the Manistee River as numerous dams in the Great Lakes
basin come up for relicensing.

Over the next two years, the researchers will continue their work on the Au
Sable and Muskegon rivers in order to create a scientific
evaluation framework that is generally applicable to Great Lakes
tributaries. From that work may just come a model case study for other
regions struggling with the conflicting goals behind sustainable ecosystem

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