Joel -
Here's a link to my search results on zebra mussels:
<http://www.looksmart.com/r_search?l&inspanel&pin=021114x2587bed5772e69a3381&search=0&key=zebra+mussel>
You should be able to choose from a number of pictures to see whether
it was zebra mussels or something else the local called zebra snails.
We've been troubled by them here in the Great Lakes for a number of
years. My brother's done a fair amount of scientific research on them
and published in (tough to read) scientific journals.
Regards,
Roger Cotner
Grand Haven, Michigan
