Download Zebra mussel

Zebra Mussel
Zebra mussel, Dreissena polymorpha, has a D-shaped stripe-patterned shell and that is
why it is called “zebra” mussel. However, not all zebra mussel shells have this striped
pattern. Zebra mussel has a size of a fingernail and it can reach the maximum length of
two inches. The zebra mussel species is considered to be invasive in North America,
Spain and Sweden, but it is considered as a native species in Black and Caspian Sea. It is
classified as one of the most fertile animals. The female zebra mussel reproduces and
spreads very rapidly in water. It tends to produce about 30,000 to 1 million egg per year.
This species was first found in northern Italy in Lake Garda in 1973. Case studies have
shown that zebra mussels are destroying eco-systems. They are threatening and killing
the local population of freshwater mussels by competing with them for food. Also, they
are destroying harbours, boats and power plants. In US, it is estimated that it costs $5
billion to recover the damages caused by zebra mussels each year. From the ecological
point of view, zebra mussels are considered to be a filter-feeding species. They increase
water quality, clarity and visibility by reducing water pollution and resulting in increased
sunlight penetration and creating a better environment for fish to live in. They remove
particles such as food from water column and feces are deposited at the bottom of lakes
as pseudofeces. They get attached to things with their byssal threads which come out
from their umbo on the dorsal side that makes removal of mussels very hard. In fact,
zebra mussels have a great nutritional value in terms of protein and carbonate content.
Therefore, crayfish and waterfowl consume zebra mussels in large quantities and
muskrats consume mussels in small quantities.
Reference:
“Zebra mussel.” Wikipedia, the free encyclopedia. Retrieved July 15, 2008, from
http://en.wikipedia.org/wiki/Zebra_mussels