By Steve
Rubenstein
San Francisco Chronicle
February 9, 2008
Scuba
divers plunged into a reservoir south of San Jose on Friday to
hunt for a tiny, troublesome shellfish that is seeking, like
so many travelers from afar, to start a new life in the Bay
Area.
In this case, it's the dread zebra mussel, a native of Russia
and the scourge of fishermen, boaters and reservoir managers
everywhere.
Last month, the mussel turned up in San Justo Reservoir near
Hollister (San Benito County), sending a chill down the spine
of state game wardens and causing authorities to close the
reservoir to boaters. The discovery spurred the Department of
Fish and Game to dispatch divers to 10 South Bay reservoirs to
see if the mussel is muscling in on new territory.
The mussel, about the size of a dime, clumps together in large
colonies that can block reservoir valves and clog water pipes
as surely as plaque in the aorta. It began turning up in the
Great Lakes in the late 1980s and it has spread - most likely
by hitchhiking rides on private pleasure boats - to Lake Mead
on the Colorado River and to several bodies of water in
Southern California.
State Game Warden Patrick Foy, one of the divers, slipped into
his black wetsuit and hopped into the murky water of Calero
Reservoir near the boat ramp and pier. He spent about 10
minutes swimming alongside the pier, feeling the structure
with his bare hands to see if mussel colonies had begun to
take hold.
Water officials stood on the shore and waited nervously, like
patients awaiting test results from the lab, while Foy's air
bubbles made a neat trail on the surface of the reservoir on a
sparkling winter morning.
After 10 minutes, Foy emerged and said the news was good - for
now. There were no traces of zebra mussels in Calero Reservoir
and there were also no quagga mussels or New Zealand mud
snails, two other invasive critters that water officials fear,
too.
"It's pitch dark down there," Foy said. "The
water is 47 degrees. You're looking very, very hard for
something you don't want to find. It's kind of odd."
The two species of mussel and the snail have no natural
enemies in these parts, and are virtually unstoppable once
established. The only surefire way to eradicate them is to
drain the reservoir.
After the divers returned to dry land, other game wardens
unveiled their new publicity campaign - dubbed "Don't
Move a Mussel" - designed to educate boaters and anglers
about the problem and urging them to inspect and clean their
boats and gear whenever leaving the water.
Ominous posters with dire warnings are being posted on docks,
parking lots and park entrances. The posters urge boaters to
wait five days between launches into different bodies of fresh
water.
Were it not for the trouble it causes, the mud snail would be
something of an admirable organism. The pinhead-size critter
has survived through the ages because it can pass, undigested
and unharmed, through a fish's gut until it is expelled at the
other end. And the snail can reproduce asexually - which means
that its messy and unsatisfying life is a testament to the
tiny snail's will to survive.
As for the zebra mussel, in the Eastern United States it has
completely clogged 3-foot-wide intake pipes, ravaged entire
water systems, consumed vast quantities of plankton, starved
indigenous species and cost the power industry more than $3
billion. A single mussel can release up to 1 million eggs a
year.
Get
involved
There
is a lot you can do to help stop the spread of invasive
species like the quagga and zebra mussels and the New
Zealand mud snail. The mussels are voracious filter
feeders and can endanger native species.
--
Thoroughly clean all equipment you use in an infected
waterway, including fishing equipment, waders, boots, boats,
rafts and inner tubes. Pets should also be thoroughly
inspected for any hangers-on.
-- When possible, freeze or completely dry any wet gear.
-- Never transfer live fish or plants from one waterway to
another.
-- Spread the word about the problems with introducing
nonnative species to new areas.
-- If you frequently fish or visit various reservoirs or
waterways, use separate pieces of equipment. For example,
use a separate pair of waders at infected areas and store
those waders separately.
-- When cleaning your boat or other equipment, don't forget
about washing vehicles and trailer hitches.
For more information, go to www.dfg.ca.gov/quaggamussel/
E-mail
Steve Rubenstein at srubenstein@sfchronicle.com
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