the invasive mussel project (imp) peter wimberger and lyle rudensey
TRANSCRIPT
The Invasive Mussel Project(IMP)
Peter Wimberger and Lyle Rudensey
Genetics and Exotic Mussels
• Marine Invasive Species• Blue Mussels and the Species
Problem• Blue Mussels on the West Coast and
Puget Sound• Genetic Monitoring of
the Mediterranean Blue Mussel
European Green Crab
Asian Copepod
Spartina or Cordgrass
Manila Clams
Ciona – a tunicate
Where do they come from?
Shipping – ballast water Aquaculture
Why are they a problem?
• Take over space/ outcompete natives• Introduce Disease• Economic Impacts ($100 billion/year!)• Impact Endangered and Threatened Species• Predators• Hybridize with native species
SPECIES CONCEPTS
Biological Species ConceptReproductive Isolation is key, but what about hybrids?
Morphological Species ConceptSpecies differ consistently in formConcept that is most used
In practice –Species are: a) groups of individuals or
populations that are reproductively isolated from each other or b) groups that for the most part retain their genetic identity over most of their range.
A little mussel historyLamy – 1936
Described group of species including Mytilus edulis, M. galloprovincialis and M. trossulus (our native species)
Soot Ryen – 1955Lumped all species together as subspecies
and races of M.edulis
Numerous workers – early 1990s Resurrect earlier 3 species as result of genetic work
Mytilus edulis – north Atlantic (both coasts)
Mytilus galloprovincialis – Mediterranean and Atlantic to England
Mytilus trossulus – “Our” native – Pacificcoast and NW Atlantic
All species can hybridize
Mediterranean blue mussels introducedto Pacific coast early 20th century through
ballast water.
Now used extensively in aquaculture (meatier, grows quickly, disease resistant)
Taken over southern Californian coastline, established in SF Bay, increasingly common in Washington and BC
More Mussel History
Blue Mussels are Sibling Species - very tough to tell apart
trossulus gallos hybrids
Genetics can do the trick!
PCR – Polymerase Chain Reaction
Way of making LOTS of specific piece of DNA
Revolutionized molecular biology– Nobel Prize ‘92
How does PCR work?
PCR Genetic Markers
Now, a number of genes w/ unique alleles in the three species
Byssal Thread Protein variants
M. edulis 180 bp M. trossulus 168 bpM. galloprov. 126 bp
PCR Gel
Mt Hybrid Mg
168 bp 128 bp
We know little about spread of gallo mussels in Puget Sound/WA
• First documented 1979
• Small surveys documented presence of gallos and hybrids in Puget Sound and Strait of Juan de Fuca in past 10 years
• Culture of gallos spreading including to SJI
• We have found hybrids throughout Puget Sound
Aquaculture will increase
Potential ecological impact - unknown
• In southern California, gallo now only mussel in intertidal
• In South Africa, gallo mussels have taken over parts of intertidal and altered community structure
• Here - ? Behooves us to know where it is and determine potential ecological effects
First question: where are gallos?
Location Trossulus Gallo Hybrids
Totten Inlet 27 12 25
Tacoma 36 0 19
South Sound
41 1 1
PS Totals 136 18 70
Second question: Can we find morphological characters to distinguish
the two species and hybrids?
Length Width
And Height (not pictured)
0
10
20
30
40
50
60H
eig
ht
(mm
)
0 20 40 60 80 100 120 140 160Length (mm)
T/G
T
G
Take-home messages
•Genetics provides a reliable way of distinguishing mussel species and hybrids
•Shape isn’t a reliable indicator of species identity
•Even though you can’t tell a book by its cover, size does matter – mussels over 65 mm are probably gallos or hybrids.
IMP participants (IMPS) can monitor and measure mussels near their schools and contributeto a growing database.