Photo: OBWB

Invasive mussels encrust a native mussel.

The Okanagan Basin Water Board is reminding residents and tourists not to move a mussel.

And, if you see mussels in local lakes, don't panic – it's almost certain they are not the invasive kind.

Following a call last week for additional resources to protect provincial waterways from invasive zebra and quagga mussels, some visitors to Beasley Park in Lake Country emailed Castanet to say their child had "pulled a good dozen mussels" from Wood Lake last weekend.

But, the water board's James Littley says: "It is unlikely that these would be invasive mussels, since there is regular testing in most water bodies in the Okanagan, and those tests have all been negative for invasives."

Littley notes there are key differences between native and invasive mussels.

Native mussels are large, usually several inches long, and will not be attached to anything. They may be partially buried in sand, but would come up easily if disturbed.

"All native mussels should be left alone, as many are endangered and protected," he says.

Invasive mussels, meanwhile, are small, only growing to about the size of a thumbnail, or a nickel. They also attach to objects using little hairs called byssal threads.

"They should still not be disturbed, but should definitely be reported. Basically, if it’s attached, it’s an invader and needs to be reported."

In either case, the rule should be "Don’t Move A Mussel!" says Littley.

As of July 5, 10 vessels entering B.C. were carrying adult invasive mussels this year.

If allowed to get a foothold, the mussels can clog waterworks, fowl beaches and threaten tourism. The OBWB says a mussel infestation would cost the Okanagan at least $42 million a year to manage.