- [Michael] In terms of surveying for native freshwater mussels, that has been done before.

And you know, it's that idea that we really don't know what's in our inland lakes.

And so let's go out and let's just start surveying them.

- Efforts are underway to get a better understanding of what's in our inland waters before it's potentially too late.

Hi and welcome back to this edition of "Pressing Matters."

It was in the 1980s when researchers first became aware of zebra and quagga mussels in our Great Lakes.

Since their discovery, these invasive species have run rampant in the biggest bodies of water surrounding us, decimating some populations of native mussels and threatening the overall water ecology.

Now, scientists wanna learn about their presence in other bodies of water in Michigan, like lakes and streams, and raise awareness about just how destructive they can be and what you can do to help prevent them from spreading.

- Prevention, because once they're established, you know, they're there, and there's nothing we can do.

- [Stefanie] Michael Hillary, with the Michigan Department of Natural Resources is working on a project that might be long overdue.

- We have those plates out there right now looking at settlement of veligers, right, or juvenile zebra mussels.

You know, veliger settle on the plate, and then the juvenile zebra mussels grow.

As far as I'm aware, that's the first time this has been studied in Michigan inland Lakes.

- [Stefanie] Hillary and his team are looking for any signs or presence of invasive mussels in our inland lakes.

Here they're diving in Lake Cadillac.

Native freshwater mussels are critical for helping filter pollution out of the water and improve overall water quality.

They also stir up vital nutrients from the bottom and providing additional food sources for fish and other aquatic animals.

David Zanata, biologist with Central Michigan University, says the role native mussels play is critical.

- Incredibly important for the overall biodiversity of the ecosystem.

They show their pattern with water quality high diversities of native mussels.

And they also, unlike zebra mussels, because they burrow, they kind of cause a lot of nutrient cycling in the sediments themselves that zebra mussels don't really do because they don't burrow.

So, really important because it allows for carbon cycling and nutrient cycling to happen more readily in those river bottoms and allows for more aeration of that bottom that otherwise wouldn't happen.

- [Stefanie] Zebra mussels spread very quickly into the Great Lakes in the late '80s with the rise of the shipping industry when they hitch ride over from Eastern Europe.

They're very small compared to several of our larger native freshwater mussels.

Quagga mussels came a few years later, both capable of the same type of destruction.

- They reproduce really quickly.

Female we're laying over like a million veligers on spawning season, so a lot.

They're broadcast spawners and so they just free float, and they settle on the hard substrates.

And, you know, they have these byssal threads, which is just protein layer that they attach to things with, and they're quite strong.

And so, you know, they've been a problem.

- A zebra and quagga mussel's typical lifespan is two to three years.

The native mussels are relatively prolific as well, and can produce tens of thousands of larvae during a season even.

The native mussels have an extra step in their lifecycle that requires the parasitism of a host fish.

And sometimes that host is quite specific in what they use, and they use that host to move around.

But that extra step complicates things and makes them less prolific overall.

- [Stefanie] Once native mussel larvae find a host fish, they'll eventually go through a type of transformation and burrow into the soft bottom of the water.

Invasive mussel settle on hard surface, including native mussels, oftentimes right near the top, depriving them of food among other things.

- They will preferentially settle on that over other hard surfaces.

With a load of a few dozen to a few hundred, sometimes even heavy densities of a few thousand, within a few months, the native mussel isn't able to move, might tip over because of the heavy load of zebra, quagga mussels on them.

They're outcompeted for the food that is getting towards them, and they can't reproduce properly 'cause their larvae are perhaps getting eaten or are getting disrupted.

So they die out within a few months to a few years after a heavy zebra mussel infestation.

- [Stefanie] Both native and invasive mussel filter water.

But without the native mussels stirring up the sea floor, having clear water can actually lead to more problems, including large algae blooms.

- It's not really a positive thing.

Aesthetically, it might look positive because the water might appear clearer, but a lot of the nutrients and potentially pollutants that were out in the water column are now down in the sediment, and that becomes much more toxic, changes the ecosystem dramatically for other bottom dwelling organisms, fish, invertebrates.

And that changes the food webs that are available to the native fauna that might have been previously present.

- [Stefanie] Managing and removing invasive species already costs millions annually.

And without prevention and awareness, that price tag will likely keep going up.

- [Michael] And we're also spending millions of dollars a year trying to manage these, you know, and clean out pipes and things like that.

Cleaning off your boats, right?

Clean, drain, dry.

And so, you know, cleaning off your boats when you're moving from different water bodies that 'cause we still have inland lakes where we do not have invasive Dreissena, so zebra mussels and quagga mussels.

And that's important, you know, from a freshwater native mussel perspective, you know, because they do pose a threat to them.

- Now in Michigan, there are roughly 45 types of native mussel species.

Researchers tell us not only are invasive species threatening the health of the Great Lakes and inland bodies of water, but climate change will also continue to play a role in the changing ecosystems.

Now, just last month, a Canadian regulation targeting invasive species went into effect, but the new rule is blocking six US carriers from accessing Canadian ports in the Great Lakes.

The measure requires ships to install technology that filters water ships take on board, also known as ballast water, to account for changing cargo loads.

Canadian officials say this will reduce the spread of invasive species.

The six American ships built after 2008 are immediately affected by the law.

Now the president of the Lake Carriers Association says the six ships have applied for a five-year exemption from the policy.

- [Jim] American ships that aren't impacted yet to move some of that cargo.

But even if that is the case, it still impacts the economics of our fleet.

I would call it a regulatory embargo.

- A US Federal Commission is currently investigating the Canadian rule for unfair trade practices.

In a statement, Canada's transportation department told WCMU the law was quote, "non-discriminatory and in the public interest."

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