Smelt die-offs in California – 04/27/2006

  • November 23, 2013 at 5:01 pm #1183

    Hi All

    Been very busy with AZ Demonstration, but this site need to keep
    going as it will prove to be an importatnt clue in the aerosol
    operation casualties.

    SNIP FROM BELOW~~director Inge Werner. “I ask, how difficult can
    this determination be?”~~

    Is it similar to the toxic lichen that killed hundred of ELK in WY?
    Is it the relentless algae blooms which have persisted for the past
    24 months?
    Is it the recent “Fish Jubilee” syndrome as was seen in the mid-
    Get busy people. All we need to do is ask the right questions and
    demand some answers. We don’t need to prove this or that, but we do
    need to be asking the questions and expecting some answers.

    SNIP~”can we identify what is causing the toxicity?” asked lab

    Delta Smelt’s Fate Worries Scientists
    The once-populous tiny fish is vanishing from the Sacramento-San
    Joaquin estuary. That may signal big trouble.
    By Bettina Boxall, Times Staff Writer
    April 17, 2006

    DAVIS, Calif. — Last summer, state fish and game workers dragged a
    net dozens of times through the milk-chocolate waters of the
    Sacramento-San Joaquin Delta, looking for a tiny, steely blue fish
    found nowhere else in the world. The catch, 17 delta smelt, was
    shockingly small.

    Never in the nearly five decades that the state has monitored smelt
    in the sprawling delta, where two of the state’s biggest rivers
    converge just east of San Francisco Bay, have their numbers been as
    dismal. So abundant a generation ago that fishermen used the
    translucent, finger-length fish for bait, the delta smelt population
    has plummeted from the millions to an estimated 100,000 or less —
    bringing it, some warn, to the brink of extinction.
    The smelt’s recent collapse, coupled with the decline of three other
    fish species that swim in the delta, has launched a multimillion-
    dollar scientific detective hunt for the reason.

    There is a sense of urgency because the smelt’s only home is one of
    California’s most important, if troubled, ecosystems. The hub of the
    state’s giant water system and a Bay Area playground, the delta is a
    vital link in the estuary chain that supports most of California’s
    commercial fish species.

    If the smelt is lost, it will be one more sign that the delta is too
    taxed to give Californians everything they demand of it.

    “The only way we’ll be able to save this estuary and the valuable
    resources it provides … is by figuring out what’s going wrong for
    this little fish,” said Tina Swanson, a senior scientist with the
    Bay Institute, which last month petitioned the federal government to
    upgrade the smelt’s protected status to endangered.

    Environmental safeguards in place for more than a decade have
    altered the operation of the big government water projects,
    sometimes even shutting down the enormous delta pumps that supply
    two out of three Californians. But that hasn’t been enough.

    “I think for delta smelt it’s looking pretty gloomy,” said UC Davis
    research ecologist Bill Bennett, who has spent much of the last
    decade studying the fish’s decline. The delta “is really not a good
    place for them to live anymore. It’s a very different aquarium these
    fish are in than it was 30 years ago.”

    The delta’s degradation started with the Gold Rush, when settlers
    drained its vast, rich tidal marshes for cropland and walled its
    meandering waterways with earthen levees. More recently, the
    estuary’s natural rhythms of flow and saltiness have been broken by
    upstream dams and delta water exports that rocketed after completion
    of the State Water Project in the late 1960s. Farm and urban runoff
    has brought a stew of pesticides and other contaminants, and an ever-
    expanding array of nonnative species competes for food and habitat.

    Yet scientists aren’t sure exactly what in that grim summary is
    pushing the smelt to the edge of survival.

    “Is it one more straw on the camel’s back or did something new creep
    in?” asked Bruce Herbold, a U.S. Environmental Protection Agency
    fish biologist who is helping coordinate the scientific sleuthing by
    a consortium of federal and state agencies.

    The smelt’s numbers began to plunge in the early 1980s. In 1993, the
    fish was listed as threatened under the Endangered Species Act. The
    Bay Institute and two other groups say the listing should now be
    changed to endangered.

    “Many of us watching the situation fully expected, because last year
    was a good water year, the numbers would be better,” said David
    Harlow, an assistant field supervisor with the U.S. Fish and
    Wildlife Service. “They aren’t.”

    Moreover, three other delta fish have also taken a dive since 2002:
    the native longfin smelt, young striped bass and — most surprising
    to biologists — the threadfin shad.

    “That blew everyone away because they had been doing wonderfully for
    years,” said Ted Sommer, a state Department of Water Resources
    environmental specialist.

    After a year of data-crunching, the science team suspects there is
    not one culprit, but many.

    Inevitably, any look at the delta turns to the mammoth government
    pumping operations in the south delta that fill the aqueducts
    carrying water to the vegetable fields of the San Joaquin Valley and
    the subdivisions of Southern California. The pumps are so powerful
    that they can reverse the natural flow in delta channels.

    In 2003, enough fresh water was sucked out of the delta to fill a
    lake the size of Los Angeles to a depth of nearly 22 feet. Delta
    water exports in the last five years have been among the highest on
    record, according to state figures, and the timing of exports has
    also changed. Less water is being pumped in the spring and more at
    other times of the year, particularly during winter, a shift that
    was intended to protect spawning female fish.

    “You can’t really deny that smelt have gone down while pumping has
    gone up, and the big crash took place when they changed the time of
    the pumping,” observed Peter Moyle, a UC Davis professor of
    fisheries biology who thinks the operation of the state and federal
    water projects “is clearly playing a major role.”

    Although screens steer fish from the pumps into collection tanks for
    transport back to the delta, the smelt are so small and fragile that
    many are sucked into the pump apparatus or don’t survive the tanks.
    The higher pumping rates, Moyle speculates, may be pulling water
    through the delta so quickly that it’s interfering with the
    production of beneficial algae and hurting the food web. And more
    fish may be dying at the pumps during the winter, before they can

    Moyle, whose work helped win the smelt endangered species
    protection, started studying the fish in the early 1970s.
    You’d go out there and do a 20-minute trawl for striped bass and
    you’d come back with a tub of fish that was mostly delta smelt,”
    Moyle recalled. “You know you’ve got them even before you see them.
    You get this waft of cucumbers” — their signature smell.

    So delicate it can die if held for an instant, the smelt remains
    somewhat mysterious. It lives for only a year, and scientists don’t
    even know exactly where in the delta it spawns — only one egg has
    been collected in the wild.

    The effect of the water projects extends beyond the pumps. Delta
    hydrology has been fundamentally altered by upstream dam releases
    that maintain a year-round supply of fresh water, disrupting the
    natural inflow pattern along with the balance of fresh and salt

    “It used to be salty in the summer and really fresh all the way down
    to Suisun Bay in the springtime, every year,” Herbold said. “And now
    it’s fresh all the time. It’s just stable. It’s the Mississippi

    That has made the delta a better home for exotic species, many of
    which were dumped into San Francisco Bay with ballast water emptied
    by ships from distant ports. Scientists have documented more than
    200 kinds of alien plants, fish and invertebrates. More arrive every
    year, making the bay-delta one of the most invaded estuaries in the

    For natives such as the smelt, that means more competition for food.
    And it means the food itself has changed.

    One invader in particular, an Asian clam known as the overbite clam
    for its mismatched shells, is a delta villain. Since its 1986
    discovery, the voracious eater has carpeted parts of Suisun Bay and
    marsh — an important fish nursery and one of the least altered parts
    of the delta.

    “It’s aliens, aliens, aliens, aliens — that’s what’s going on in the
    delta, this huge invasion and dominance of alien species,” said B.J.
    Miller, an environmental engineer who consults for major federal
    water contractors dependent on delta supplies. He argues that the
    focus on water exports is overblown.

    Scientists are also examining the effect of toxics. Pesticides,
    industrial pollutants, mercury from 1860s Sierra gold mining — all
    can be found in the delta. In recent years, Central Valley farmlands
    that drain into its waters have switched from a class of pesticides
    harmful to humans to pyrethroids, which are better for people but
    poisonous to aquatic organisms.

    At the Aquatic Toxicology Laboratory at the UC Davis School of
    Veterinary Medicine, researchers bathe amphipods, tiny crustaceans,
    in beakers of delta water for 10 days to see if they grow or die. In
    similar testing last year, 5% of the delta water samples were toxic
    to the creatures, a crucial part of the food chain.

    Using hatchery fish, the lab is about to conduct the same sort of
    experiment with striped bass and delta smelt. “Is the water toxic to
    aquatic organisms, and if it is, can we identify what is causing the
    toxicity?” asked lab director Inge Werner.

    At another Davis lab, pathobiologist David Ostrach has been studying
    striped bass since the late 1980s. A few years ago he found that
    eggs from females captured in the Sacramento River upstream from the
    delta were contaminated with chemicals such as PCBs and flame
    retardants that interfered with larval growth and development.

    “You have an animal that right at first feeding is set up to fail,”
    Ostrach said. “Those are fairly disturbing results.”

    But he can’t say if that sort of individual effect helps explain the
    recent tumble in overall fish numbers.

    The delta’s fish troubles, Ostrach suspects, are manifold.

    “I don’t believe they’re going to put their finger on any one
    thing,” he said of researchers. “It’s multiple things causing
    multiple problems.”

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