ZEBRA/QUAGGA MUSSEL(Dreissena
polymorpha)
|
Zebra Mussel |
Quagga Mussel |
ZEBRA
MUSSELS |
QUAGGA
MUSSELS |
|
Shell |
Triangular shape, byssal (ventral) side flat. Obvious ridge between side and bottom | Rounder sides, byssal side rounded. ridge lacking |
Color |
Variable colors and patterns, usually dark | Pale near hinge, dark concentric rings on the shell |
Byssal |
Large groove in middle of flat side; allows tight hold on rocks | Small byssal groove near the hinge |
Depth
in Lake |
3 to 98 feet (1-30 m), rarely found below 50 feet (15 m) | 3 to 351 feet (1-107 m), commonly found down to 98 feet (30 m) |
Temperature |
32° to 86°F (0° to 30°C) |
32° to 86°F (0° to 30°C) |
Tolerance |
54° to 68°F (12° to 20°C) preferred |
39° to 68°F (4° to 20°C) preferred |
Reproductivity
Temperature |
Young present at 57 ° to 68°F (14° to 20°C) | Young present as low as 46°F (8°C) |
SPREAD
Zebra mussels were introduced to North America from the ballast
water of a ship that traveled to the Great Lakes from the Ponto-Caspian
area. Since their discovery in Lake St. Clair in the mid 1980s they spread
quickly to all of the Great Lakes, and many other waterways including
the St. Lawrence Seaway and the Hudson, Illinois, Mississippi, Ohio, Arkansas,
and Tennessee rivers. The mobility of their veligers (plankton stage)
has enabled the zebra and quagga mussel to invade the Great Lakes as well
as the entire stretch of the Mississippi River. During this stage, they
can float in the water for up to four weeks before they settle and attach
to a solid surface. In addition, zebra mussels and quagga mussels can
hitchhike on boat hulls and trailers to other lakes if boaters are not
vigilant about cleaning.
2002 Distribution of Zebra Mussels
2005 Distribution of Quagga Mussels
IMPACTS
Zebra and quagga mussels are excellent filter feeders, removing large
amounts of plankton
and suspended particles from the water. By removing plankton, the mussels
decrease the food available for fish and other consumers. This food web
disruption, in turn, can cause great change to aquatic communities. Zebra
and quagga mussels can also accumulate high levels of contaminants within
their tissues, increasing wildlife exposure to contaminants through the
food chain. The zebra and quagga mussel can clog water intake structures,
such as pipes and screens, disrupting supplies of drinking, cooling, processing,
and irrigation water. Recreation-based industries become heavily impacted
by the mussels when docks, break walls, buoys, boats, and beaches become
heavily colonized.
PREVENTION AND CONTROL
Veligers may be carried in livewells,
bilge
water, or bait buckets. Adult mussels can easily attach themselves to
boat hulls and trailers. To prevent chances of introducing these species,
boaters should drain water from the motor, live well, bilge and transom
wells, and any other water from the boat and equipment while on land
before leaving any water body. Zebra and quagga mussels also cling to
vegetation, so great care should be taken to clean off all vegetation
from the boat, trailer, and motor before transporting it to another body
of water.
The European community, after two centuries of infestation, and the Great Lakes community, after years of infestation, haven't been able to develop a chemical toxicant for lake wide control that is not deadly to other aquatic life forms.
FOR MORE INFORMATION ON THE ZEBRA AND QUAGGA MUSSEL
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