Nuisance “Quagga” mussels found at Lake Pleasant
Quagga mussels have been discovered at multiple sites at Lake Pleasant, and state wildlife officials are requesting that boaters and other recreationists take simple steps to help prevent this Eastern European menace and other aquatic hitchhikers from spreading to other lakes.
On Dec. 17, small adult mussels were collected from a dry-docked boat that had been moored at Pleasant. A team of biologists from the Arizona Game and Fish Department also discovered mussels in the southern end of the lake from boat slips at the Lake Harbor Marina, at the Pleasant Harbor Marina boat launch, and the 10-lane boat ramp courtesy dock. Those invasive mollusks have been confirmed as quagga mussels.
Quagga mussels, which have caused millions of dollars in damage in the Great Lakes region, were first discovered at Lake Mead in January of this year. Since then, they have been confirmed in lakes Mohave and Havasu and their presence has been suspected, but not confirmed, at Lake Powell. This past fall, quagga mussels were discovered in a segment of the Central Arizona Project (CAP) Canal in Scottsdale. The CAP canal originates at Lake Havasu. Water from the CAP is used to fill Lake Pleasant.
Game and Fish Department officials are asking all boaters and anglers throughout the state to help fight the continuing spread of these and other invaders by routinely taking simple precautionary steps each time they visit a waterway anywhere in the state.
Before leaving a lake or other waterway, always:
- CLEAN the hull of your boat, remove all plant and animal material.
- DRAIN the water from the boat, livewell and the lower unit.
- DRY the boat, fishing gear, and equipment.
If you are a day user, please wait five days before launching your boat someplace else. This five-day waiting period will aid tremendously in killing those hidden hitchhikers on your boat, such as the microscopic quagga larvae. Also, it is a good idea to wash the hull of your boat with high-pressure water, either at the lake, if washers are available, or after leaving the waterway.
Visiting a self-help car wash that has high-pressure soapy water is an excellent idea either on your way home, or while on the way to the next lake – it can even help keep your boat looking new. Or, giving your boat a hot soapy bath when you get home can also help protect your investment and while also helping protect the next lake you visit.
Remember, many of these aquatic hitchhikers can harm your boat as well. These invaders will attach themselves to boats and can cause damage to boat motors if they block the flow of cooling water through the engine.
If you are moving a boat that has been moored on a mussel-positive lake, please take at least one of these extra precautions:
- Power wash the hull so that it is clean “to the touch”
- Bilge decontamination that consists of either a 140-degree hot water flush of the bilge spaces OR
- A household vinegar flush of the bilge spaces, OR
- A 27-day desiccation period where the boat is removed from the waterway and allowed to dry out; all through-hull fittings and bilge plugs must be opened to the air with no residual lake water allowed to remain standing in the bilge spaces; if, for any reason, water cannot drain or standing water remains in the bilge, it must be treated with heated water or vinegar solution.
Quagga mussels do not pose a known threat to human health. Biologists are concerned that quagga mussels may cause ecological shifts in the lakes they invade, with consequences to valued wildlife resources.
Because these invasive mussels attach to hard surfaces like concrete and pipes, they will affect canals, aqueducts, water intakes and dams, resulting in increased maintenance costs for those facilities.
For more information, click here or visit ww.100thmeridian.org.
Frequently
Asked Questions
What
are quagga or zebra mussels?
| Zebra
mussels (Dreissena polymorpha)
are small, freshwater bi-valve mollusks
(relatives to clams and oysters) that
are triangular in shape with an obvious
ridge between the side and bottom.
The zebra mussel gets its name from
the black- (or dark brown) and white-striped
markings that appear on its shell. |
| |
|
Where
did quagga or zebra mussels come from?
Quagga
mussels are native to the Dneiper River
drainage of the Ukraine. Zebra mussels
are native to the Caspian, Black, and
Azov seas of Eastern Europe. These exotic
mussels were first discovered in the United
States in Lake Saint Clair, Michigan,
in 1988 and are believed to have been
introduced in 1986 through ballast water
discharge from ocean-going ships. Since
their initial discovery, zebra mussels
have spread rapidly throughout the Great
Lakes and Mississippi River Basin states
and other watersheds throughout the eastern
and central United States. Quagga mussels
have not spread as extensively.
How
did these invasive mussels get to Lake
Mead?
These
invasive mussels in Lake Mead are 1,000
miles farther west than any other known
colony of zebra mussels. The primary
method of overland dispersal of these
mussels is through human-related activities.
Given their ability to attach to hard
surfaces and survive out of water, many
infestations have occurred by adult mussels
hitching rides on watercraft. The microscopic
larvae also can be transported in bilges,
ballast water, live wells, or any other
equipment that holds water.
What
do they eat?
They are primarily algae feeders.
They feed by filtering up to a liter of
water per day through a siphon.
Why
should we be concerned about these mussels?
These
mussels are filter feeders that consume
large portions of the microscopic plants
and animals that form the base of the
food web. The removal of significant amounts
of phytoplankton from the water can cause
a shift in native species and a disruption
of the ecological balance of the lake.
These
mussels often settle in massive colonies
that can block water intake and affect
municipal water supply and agricultural
irrigation and power plant operation.
In the United States, Congressional
researchers estimated that zebra mussels
alone cost the power industry $3.1 billion
in the 1993-1999 period, with their impact
on industries, businesses, and communities
more than $5 billion.
Mussels
were only found in one area of Lake Mead.
How can that become a problem?
These
invasive mussels can live for three to
five years and can release 30,000 to 40,000
fertilized eggs in a breeding cycle and
one million fertilized eggs in a year.
Do
these mussels have any predators?
These mussels do not have many
natural predators in North America, but
it has been documented that several species
of fish and diving ducks have been known
to eat them.
What
can I do to help?
It is up to each of us to take
extra precautions to stop the spread of
mussels or any other invasive species.
The following actions should be taken
with any equipment used in potentially
infested waters:
-
All
equipment (e.g., dive gear, boats,
trailers, motors, etc.) should be
visually and tactically (by feel)
inspected for the presence of zebra
mussels prior to and after use in
any water body. Additionally, any
vegetation attached to this equipment
must be removed and left at the site
of origin.
-
Remove
all sediment and gritty organic materials;
these could actually be zebra mussel
veligers (juveniles).
-
Clean
and scrub boat hulls, motors, anchors
and trailers. Then hose equipment
with hot (140° F) and/or high-pressure
water. Bilges, live wells, and
any other compartments that could
hold water should be drained at the
site of origin, and, if possible,
flushed with disinfectant or hot water.
All boat equipment should be allowed
to remain completely dry for at least
24 hours before being used again.
-
Thoroughly
clean all equipment in a saltwater
bath (1/2 cup per gallon) or with
warm tap water (104 ° F). Ensure
that all equipment remains completely
dry for at least 24 hours before being
used again. Pay special attention
to those areas and equipment that
can hold water.
-
Take
similar precautions with waders, bait
buckets, and other equipment that
can hold water or comes into contact
with water.
Map
of Lake Mead
Zebra
mussels were found at Las Vegas Boat Harbor
and Lake Mead Marina on 1/6/07. See anchor
icons above.
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