Fish die-off in California – 06/19/2005

  • October 23, 2013 at 2:50 am #715

    Posted on Sun, Jun. 19, 2005
    Agencies mount strategy against Delta fish die-off
    By Mike Taugher

    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
    fragile levees.

    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,”
    he said.

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