[env-trinity] Modesto Bee: Study: Salmon don't want too much water

[Sari Sommarstrom]

Journal article:
http://www.tandfonline.com/doi/abs/10.1080/02755947.2016.1240120?journalCode
=ujfm20

 

Modesto Bee editorial, 1-19-17
http://www.modbee.com/opinion/editorials/article127580214.html

Study: Salmon don't want too much water 

One of FishBio's salmon-counting weirs on the Stanislaus River.

One of FishBio's salmon-counting weirs on the Stanislaus River. Jeff Jardine
jjardine at modbee.com 

By the Editorial Board

Salmon don't read memos or get emails from the state Department of Water
Resources, nor do they consult U.S. Fish and Wildlife Service instruction
manuals. So how can they possibly know when it's time to spawn? 

Over hundreds of thousands of years, salmon have learned to "read" signals
that nature provides and only they truly understand. Those signals tell them
when it's time to swim upstream. 

A group of FishBio scientists working on the Stanislaus River have crunched
11 years of meticulously kept data to better understand those signals.
FishBio concluded that, using "adaptive management" techniques, government
regulators often sent the wrong signals. In fact, their efforts were
sometimes counterproductive in helping salmon populations recover. 

Why? Because more water does not equal more fish. 

In a peer-reviewed study published this week, FishBio looked at river
conditions and flows from October through December, when the most salmon
were moving up the Stanislaus River. The scientists caution against jumping
to conclusions, but they say the state frequently releases too much water. 

Optimum flows to entice salmon to spawn are around 700 cubic feet per
second,  <http://www.tandfonline.com/doi/full/10.1080/02755947.2016.1240120>
says the study. That's roughly 5,100 gallons per second; a lot of water. But
it's far, far less than what the U.S. Bureau of Reclamation, which operates
New Melones Dam, usually releases.
<http://cdec.water.ca.gov/cgi-progs/selectQuery?station_id=GDW&sensor_num=8&
dur_code=D&start_date=2010-10-25&end_date=2010-12-31&geom=>  In 2010, the
bureau released at least three times that much for 14 straight days -
exceeding 10,000 cfs (15 times the optimum) for three days.

How much water is that? About 4.4 million gallons in a minute, enough in
three hours to flood Oakdale 3 feet deep. Over the course of these "spike"
flows, the bureau usually sent some 25,000 acre-feet of clear water to
attract salmon that often never came.

"If you hold (flows) up for more than a day or two, it's not providing any
benefit," said FishBio's Andrea Fuller, one of the authors with FishBio
partner Doug Demko and staffer Matthew Peterson. "If we didn't have the dams
in place, we'd have a very flashy system - the flows would spike up to a
high degree, then recede quickly. The volume of water we're putting down in
October wouldn't have happened in even the wettest years."

Does this mess with the salmon's internal signals? "Big time," Fuller said.

"What led to the study, (the bureau) started doing these (adaptive
management) releases in the 1990s and there was an agreement that there
would be an assessment to see how well they worked," Fuller said. "But that
was never done. We were left asking, 'How did you come up with the volumes
of water you think is needed?' 

"This finally gives us a study to see how the fish are responding." 

Those who still cling to the writ of "more water equals more fish" will
dispute FishBio's studies. But the prestigious
<http://www.tandfonline.com/toc/ujfm20/current> North American Journal of
Fisheries Management subjected it to review by three scientists not
associated with FishBio. It's solid. 

The study doesn't directly address the State Water Resources Control Board's
ongoing efforts to double the amount of water dedicated to environmental
purposes on the Stanislaus, Merced and Tuolumne rivers. But it does argue
that the state's "adaptive management" assumptions should be subjected to
close scrutiny. It should also convince the Bureau of Reclamation to reduce
the water it releases each fall, meaning more would be left behind the dam
in April and early May when juvenile salmon are trying to exit the river. 

FishBio's study contains some very important signals. Not for the salmon,
but for state and federal scientists. They should reconsider their positions
and base their demands on the facts they find on our rivers - not disputable
dogma.


Read more here:
http://www.modbee.com/opinion/editorials/article127580214.html#storylink=cpy

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www2.dcn.org/pipermail/env-trinity/attachments/20170124/69cb3823/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.jpg
Type: image/jpeg
Size: 35323 bytes
Desc: not available
URL: <http://www2.dcn.org/pipermail/env-trinity/attachments/20170124/69cb3823/attachment.jpg>