Zebra Mussels

1
Zebra Mussels
2
What are Zebra Mussels?

• Scientific Name
• Dreissena polymorpha
• Zebra mussels are small shellfish (as small as a
  kidney bean)
• Although variable, most have a striped shell
  pattern
• Multiple color patterns
• Some of the zebra mussels have no stripes

3
Name Origin

• The species name of the zebra mussel scientific
  name polymorpha means many forms, like their
  color varieties
• Zebra mussels are members of the phylum Mollusca
  (mol-US-ka), or mollusks
• Mollusca is from the Latin word mollis, which
  means soft
• All slugs, snails, octopi, clams, and oysters are
  mollusks
• Mussels are bivalve mollusks
• Bivalves have two shells that are held together
  by a strong ligament

4
(No Transcript)
5
How quickly do they multiply?

• Each Zebra mussel is able to produce from thirty
  thousand to one million eggs each year
• All fertilized eggs develop quickly into
  free-swimming larvae called veligers
• Veligers are smaller than the period at the end
  of this sentence.
• Veligers feed on tiny phytoplankton (such as
  algae or small freshwater plants), and by
  drifting with water currents they can travel
  great distances

6
Veliger larvae of the Zebra Mussel photographed
using two different light sources.
7

• After three to four weeks, they must find
  something to attach to or die
• Once they have attached themselves, the veligers
  change from free-swimming larvae to anchored
  mussels
• However, 95 of veliger larvae do not survive
  this stage
• Young zebra mussels reach their sexual maturity
  during their first year

Zebra mussels attached to a flow meter in Lake
Michigan
8
Predators

• Zebra mussels have high nutritional value, and
  are consumed in large quantities by crayfish,
  waterfowl and muskrats
• Nutritional value changes seasonally, varying in
  protein and carbonate content
• Crayfish can have a significant impact on the
  densities of 1 to 5 mm long zebra mussels. An
  adult crayfish consumes an average of nearly 105
  zebra mussels everyday, or in all about 6000
  mussels in a season. Predation rates are
  significantly reduced at cooler water
  temperatures.
• Also, fishes of the carp and minnow Family
  (Cyprinidae) are known to consume zebra mussels

9
Where did zebra mussels originate?

• Zebra mussels originally came from the Black,
  Caspian and Aral Seas
• By the late 18th and early 19th centuries, zebra
  mussels spread to most of the major drainages of
  Europe
• This was due to the widespread construction of
  the canal system
• Zebra mussels were able to spread to Great
  Britain by the 1830s

10
Dispersal

• Adult Zebra mussels travel on boats, attached to
  the hull or other surface
• Larvae can travel in the ballast water of ships
• When a ship travels out into the open ocean, it
  needs to carry extra weight (ballast) in order to
  maintain an even keel (stability). Nowadays the
  most common form of ballast is water.
• The water that is used for the ballast (along
  with anything that is in it) is picked up in the
  homeport, carried with the ship, and then is
  dumped out as they prepare to load cargo
• So, wherever the ship goes, so does whatever else
  that is on it. An entire field of study, ballast
  ecology, developed during the 1990s.

11
Arrival in America

• Jonathan Bossenbroek, an ecologist at the
  University of Toledo, believes that the zebra
  mussel initially entered the United States in
  1988
• This was most likely through the ballast water
  from international cargo ships traversing the
  St. Lawrence Seaway
• Another possible mode of introduction is on
  anchors and chains, although this has not been
  proven
• Zebra mussels were first noticed in Lake Erie and
  Lake St. Clair since then they have spread
  throughout much of the Eastern United States and
  Canada

12
Lake St. Clair and Lake Erie were the first
recognized North American locations of the zebra
mussel
13
Where are they spreading?

• Since their release into Lake St. Clair and Lake
  Erie, zebra mussels have been found in all five
  Great Lakes
• They have even been spotted in the St. Lawrence
  River, the Finger Lakes region of New York, and
  the Mississippi River basin

• Many Division of Natural Resources officials are
  worried that the zebra mussels will make it up to
  Maine, since Vermont has been effected
• Zebra mussels are even pushing out west, having
  been found in Lake Powell and the Colorado River

14
Map of the zebra mussel sightings throughout the
United States up to April 2005. However, there
are now sightings of zebra mussels in California,
Colorado, Kansas, Oklahoma, and parts of Iowa
(the following site has an updated
map) http//nas.er.usgs.gov/taxgroup/mollusks/zeb
ramussel/zebramusseldistribution.asp
15
How can they move so quickly?

• Cargo shipping via the worlds waterways has
  increased greatly in the past 50 years thus
  increasing the chance for introductions via
  ballast water.
• Adult zebra mussels readily attach themselves to
  boats and can survive out of water by simply
  closing their shells tightly
• Since boats do not stay in one place, the zebra
  mussels that attach become mobile

16
Slow the spread

• In order to avoid spreading zebra mussels to new
  areas, agencies advise you to keep your boat
  clean
• The general recommendation is to keep the vessel
  out of water and dry for a minimum of 30 days
  after cleaning all equipment and draining all
  possible sources of standing water
• Quarantine times may be reduced due to local
  temperatures or relative humidities

17

• Recommended quarantine times when drying out a
  boat
• January - 51 Days
• February - 32 Days
• March - 21 Days
• April - 13 Days
• May - 8 Days
• June - 5 Days
• July - 5 Days
• August - 5 Days
• September - 5 Days
• October - 13 Days
• November - 21 Days
• December - 51 Days

• Zebra mussels can survive for a long time out of
  water
• In fact, adult zebra mussels can survive out of
  water for several days or weeks if the
  temperature is low and humidity is high

18
How are zebra mussels harming the marine life?

• Zebra mussels have been known to affect the
  natural ecosystems both directly and indirectly
• One of their most noticeable impacts is their
  feeding behavior
• Since zebra mussels are filter feeders, they take
  up everything in the water, about one gallon per
  day per mussel

• All particles within the water column of any
  infected area are removed or eaten by the mussels
• Non-digestible items are wrapped in mucus and
  spit out, falling to the ocean floor
• Whenever high densities occur, zebra mussels are
  capable rapidly clearing the water

19

• When lakes clear up, the light level increases,
  causing the aquatic plants to increase in both
  number and size
• This increase could be beneficial to some fish
  such as the northern pike and yellow perch
• However, this can cause problems for recreational
  boaters and swimmers
• There is also a possibility of increasing taste
  and odor problems with drinking water supplies,
  as zebra mussels can block water-intake pipes
  during a heavy rain event

20
What other harmful affects do zebra mussels
have?- remember, Everything is connected to
everything else

• Benthic macroinvertebrates (tiny invertebrates
  such as Diporeia) play a major role in the food
  chain and by cycling materials
• However, changes are occurring within the food
  web due to zebra mussels, including major
  changing within benthic macroinvertebrate
  populations
• Many fish species, like whitefish, feed on
  Diporeia, and when their numbers decline so do
  their predators

Diporeia
21

• One of the more drastic impacts of zebra mussels
  are their influence in causing the near
  extinction of native American unionid clams in
  Lake St. Clair
• Also found to be the case for the western basin
  of Lake Erie
• Zebra mussels will attach and build colonies on
  native species of clams, hindering movement and
  overall fitness

Zebra mussels attached to a native clam found
within the Great Lakes region
22
Interesting Zebra Mussel attachments

• Sometimes they even attach to one another
• Zebra mussels tend to colonize on just about
  anything, including native clams, boats, plants,
  and slow moving animals
• Zebra mussels have also been known to attach to
  trash that can be found in water bodies

Terrible waste of a good beer can
Zebra mussels attached to a crayfish (top) and a
snapping turtle (bottom)
23

• Since zebra mussels attach to water intakes,
  surrounding areas could go for days without any
  water
• Companies that use water to power their plants
  can have trouble keeping them up and running
• A number of plants in the Great Lakes regions are
  having trouble keeping the zebra mussels out of
  their water intake pipes

Zebra mussels encrusted inside water pipes
24
(No Transcript)
25

• The 100th Meridian Initiative represents the
  first comprehensive and strategically focused
  effort
• This effort is in cooperation with federal,
  state, tribal and provincial agencies that
  address potential pathways to prevent the
  westward spread of the zebra mussels
• Also works to stop other aquatic nuisance species

• Some of the goals of the 100th Meridian
  Initiative include
• Preventing the spread of zebra mussels and other
  alien species in the 100th meridian jurisdictions
  and westward
• Monitoring and controling zebra mussels and other
  alien species if detected in these areas
• Goals can be achieved by
• Information and education
• Voluntary boat inspections
• Monitoring
• Rapid response

26
This map shows the dividing line for the 100th
meridian the right side is where most of the
zebra mussel populations are found, and the left
side where populations are starting to appear
27
Why the big concern?

• If the zebra mussels do get past the dividing
  line, major problems can start in water systems
  throughout the west
• It could devastate water resource projects, raw
  water users, and also harm aquatic ecosystems
• When zebra mussels infest the headwater
  reservoirs, they are more than likely to inhabit
  and colonize thousands of canals used to
  transport water to millions of people
• Since water is very important for agriculture,
  the 100th meridian is worried that zebra mussels
  will get into the water system used for crops

28
Ways to Control the Problem

• Word of mouth is crucial to educating the public
• Information is being disseminated through
  numerous ways including print, electronic
  sources, news coverage, billboards, etc.
• As boaters move closer to the dividing line,
  information about the zebra mussels is more
  intense

• Trained personnel are stationed along 11 major
  highways to conduct voluntary boat inspections
  and boater surveys
• The 11 major highways are
• US2 I-40
• I-94 I-20
• US12 I-10
• I-90 I-44
• I-80
• I-70
• US54

29

• Boat inspections are taking place at weigh
  stations, highway rest areas/welcome centers,
  restaurants and service/motel complexes on
  interchanges
• Most inspections target boats and trailers
• Effective monitoring is important to ensure that
  zebra mussels are detected before they reach open
  waters

• Early detection of zebra mussels can decrease
  their potential impact on native resources,
  man-made structures, and the economy
• Waterways west of the 100th meridian will be
  assessed by federal and state agencies to
  determine their potential for zebra mussel
  infestation

30
One of many signs along the 100th meridian
emphasizing to boaters the potential spread of
exotic species. These are up at boating docks and
rest stops along highways
Boat inspections take place in many locations,
due to the zebra mussel being able to cling to
multiple surfaces
31
The Cost of Control- a series of examples

• For example, by 2001, Wisconsin Electric Power
  Company reported that they were spending 1.2
  million per year in control efforts
• In 2003, 12 North American nuclear plants
  infested with mussels spent on average 825,000
  per year each for control
• In Canada, Ontario Hydro has reported zebra
  mussel impacts of 376,000 annually per
  generating station (1994)
• The estimated annual cost of controlling zebra
  mussels in the Great Lakes is from 100 to 400
  million dollars (2004)
• The U.S. Fish and Wildlife Service estimates the
  potential economic impact to be at least five
  billion dollars over the next ten years to U.S.
  and Canadian water users within the Great Lakes
  region alone (2003)