October 23, 2013 at 2:50 am #715MikeKeymaster
Posted on Sun, Jun. 19, 2005
Agencies mount strategy against Delta fish die-off
By Mike Taugher
CONTRA COSTA TIMES
Scientists are planning triage over the next four months to examine
possible explanations for a widespread population crash among Delta
fish and food organisms.
The initial research effort is not expected to solve the mysterious
ecological crisis, but is designed instead to shorten a dauntingly
long list of suspects so that a more focused probe can begin next
Details of the $2 million research plan were forwarded to Rep. George
Miller, D-Martinez, who last month demanded to know why scientists
involved with the CalFed water project did not warn of the developing
crisis and what they plan to do about it.
In response to a May 1 report in the Contra Costa Times, Miller and
15 other congressional representatives challenged state and federal
agencies, saying that recent developments appear to belie a key
assumption at the heart of California water policy — that more water
can be delivered to farms and cities without further damaging the
“We agree that the apparent fish declines demand immediate and
comprehensive study and response,” the agencies wrote back to
Miller, “however, we must emphasize that this is a new issue, not an
old problem that has been neglected.”
The ecological crisis is surfacing 10 years into an ambitious effort
to tackle California’s thorniest and most politically divisive water
issues by embarking on a comprehensive effort to restore ecosystems,
boost water supplies, improve water quality and address the Delta’s
The sprawling program, called CalFed, has spent $3 billion in local,
state and federal money since 2000, but the bond funds that have kept
it afloat will begin running out in the next couple of years.
There is no plan to stabilize CalFed’s finances, and an ecological
collapse in the Delta threatens to undermine the very promise CalFed
made — that more water can be delivered to the Central Valley and
Southern California at the same time ecosystems are restored.
Meanwhile, plans to increase the capacity of Delta pumps are
continuing, though they have been delayed several times, and water
managers are continuing to issue 25-year water contract renewals to
Central Valley farm districts that lock in obligations to provide
large amounts of water from the Delta.
“The data suggest that the wheels have come off the wagon and they’re
running down the field full speed,” Miller said.
The agencies wrote to Miller that they needed three years of data
before they could draw conclusions about recent ecological trends.
When they analyzed the data in January, the agencies confirmed a
widespread, unexplained and rapid decline in the Delta’s open-water
fish populations. The agencies say that they acted promptly after
that to bring the information to government managers and scientists.
The analyses showed the population of Delta smelt, a little 2 1/2-
inch fish that is seen as indicative of the overall health of the
Delta, is at its lowest level ever. Tiny copepods, the key food
source for small open-water fish species, are in rapid decline, too.
Previously common threadfin shad also are disappearing.
The declines cannot be explained by the weather — snow and rain
patterns have been moderate — and the crash is occurring across all
of the dominant pelagic, or open-water, fish species.
“Something has changed in the estuary to cause new conditions that
are unlike our past experiences,” the agencies wrote.
Tina Swanson, a senior scientist at the Bay Institute, said that for
years there have been clues that a crisis was coming, but momentum to
advance plans to move more water from the Delta overrode concerns
about the Delta’s health.
“There was unwillingness among some agency managers and staff to
recognize the chronically low numbers,” she said. “There was probably
a sincere hope that this was a normal fluctuation. But they didn’t
want to see. And if they saw, they didn’t want to talk about it,
particularly at the same time CalFed was trying to increase exports
from the Delta.”
The science plan notes that, “While several of these declining
species … have shown evidence of a long-term decline, there appears
to have been a precipitous ‘step-change’ to very low abundance during
It is unknown whether the drop and the surprise with which it caught
water and wildlife agencies was due to CalFed decisions or actions.
But in the meantime, scientists are hoping to find some solid clues
to help them explain and correct the Delta’s decline before it
The prime suspects fall into three broad categories: toxins from
Central Valley pesticides, in-Delta spraying of aquatic weeds and
other sources; invasive species that are dramatically changing the
Delta ecosystem; and pumps that send trillions of gallons each year
to the Central Valley and Southern California. Those pumps have been
running at near-record levels the last two years.
Scientists say it is most likely that more than one suspect is to
For example, a blue-green algae called mycrocystis aeruginosa has
become more abundant in the Delta in recent years and is now growing
in clumps that are unlike what had been seen before. Mycrocystis
produces cancer-causing toxins, and one scientist said there is some
information to suggest that the way it grows might be affected by a
certain class of pesticide that has become popular on California
farms. Those pesticides, pyrethroids, are themselves more toxic to
fish than the organophosphate pesticides they are replacing.
Another possibility is that attempts to reduce pumping’s effects on
fish have had the unintended effect of undermining the aquatic
ecosystem. Ten years ago, the timing of water deliveries was moved
from the spring, when pumping can destroy migrating juvenile salmon
and resident fish near the pumps, to later in the year. That shift
led water managers to release water from upstream dams later in the
The result is that water in the summer now flows through the Delta
quicker and phytoplankton, which forms the basis of the aquatic food
web, has less time to bloom.
“We have no shortage of possible explanations,” said Bruce Herbold, a
fisheries biologist at the U.S. Environmental Protection Agency who
is a member of the team of scientists designing the investigation
into the Delta fish crash.
The plan calls for two dozen actions, including new studies, stepped
up monitoring efforts and more thorough analysis of existing data.
Researchers plan to examine fish livers for toxins, collect
information about microcystis and examine the use and toxicity of
herbicides used by the state Department of Boating and Waterways to
control nuisance plants.
“In my view, some of this work should have been done long ago,” said
Herbold said the research effort is set back somewhat because for
years CalFed focused less on the aquatic environment and more on
improving water supplies and restoring wetlands and salmon habitat.
“It’s been a frustrating experience to get CalFed to take on water
quality really as a serious issue in the same way it was taking on
ecosystem restoration and water supply,” Herbold said.
“Now, we’re looking at it (but) we’ve spent most of CalFed’s money,”
The forum ‘Strange Animal Deaths’ is closed to new topics and replies.