(upbeat new age music) - They're tiny, highly carnivorous predatory zooplankton.

They're, you know, a really devastating invasive species and not that many people know about them.

Spiny water fleas are an invasive zooplankton that have been in Minnesota since at least the 1990s, in terms of our inland lakes.

It, it is from Europe and Eurasia.

It came in on the Great Lakes shipping industry through the channels and got to our harbor in Lake Superior and has spread inland since.

And they're really disruptive to aquatic food webs because they eat a lot of the native zooplankton that are really important for baby perch and walleye.

But then on the other hand, spiny water fleas are almost basically inedible for other small fish because they have a long barbed tail spine.

So it's high energetic cost for a fish to eat that, even if they can fit it into their mouth.

One study looked at how zebra mussels and spiny water flea were affecting yellow perch and walleye in what we know as Minnesota's nine large walleye lakes Mille Lacs Kabetogama, Rainy, the the big popular walleye lakes.

And they looked at the food webs of those lakes and they also had 35 years of Minnesota DNR fall staining surveys.

What they found was that in lakes that had zebra mussels and spiny water flea, walleye growth was 25% smaller going into their first winter.

So that's because these baby fish in their first year, they are mostly eating zooplankton and they can't eat spiny water fleas.

The family of native plankton that eats a lot of phytoplankton is they're called Daphnia.

And those are really important parts of a lot of our upper Midwest aquatic food webs because they are grazers, they are eating all the algae that keep our, keeps our lake in balance and slows down those algae blooms.

I do really appreciate being out on a lake with a healthy ecosystem and seeing the fish that are present and knowing that spiny water fleas dramatically destabilize that and can lead to major algae blooms is just kind of scary.

Spiny Water flea only actually lives one season, but they form these resting eggs that can, they drop down into the sediment when the water starts to get cold, and we're going into winter, and those eggs will typically hatch out the next spring or summer.

Or if conditions are unfavorable, they'll just stay in the sediment up to three to five years and they'll hatch out when conditions are good.

They have explosive reproductive rates so they can, we're talking about exponential growth, so very high impact species.

The even scarier thing is that there are no control options at this point and not even really anything in the research pipeline.

So the only thing we can do is prevent further spread and try to get a better handle on where they currently are.

We have a protocol that's available on our website that anybody can download, teaches people how to do the sampling.

This is our basic setup.

If, if you're interested in doing spiny water flea surveillance monitoring.

The most important thing and the most specialized tool is this plankton net.

And this is used to do what we call a vertical plankton tow.

And you get on your boat or canoe, you wanna find the deepest part of the lake.

This has some weights at the bottom to keep it vertical in the water column.

And you just lower this all the way to the bottom and slowly pull it back up.

And so what this is doing is taking in this big volume of water, you're dragging it through and you're getting a little snapshot of the tiny organisms that live in the water column.

You pull it up, you shake it out, and then all the little critters are gonna be either at this collection cup or along the side.

And then you can open up your little drain hole here.

And then what we do is we just rinse it down with water from the lake.

And so this is just drawing all the critters that are caught up on the walls down into the bottom until this is fully dry.

Then you're basically just going through your sample to see if you caught anything.

Spiny water fleas are gonna be pretty visible.

That's, that's one of the things that makes this surveillance approach very achievable for volunteers is you don't need specialized equipment, you don't need a microscope, you don't have to send your sample to a lab.

If you do find spiny water fleas, take pictures with your smartphone and also save some samples in a jar in isopropyl alcohol and get those to your local D-N-R-A-I-S specialist.

(slightly ominous jumpy music) They have been found in 23 lakes.

There was one new detection found last summer, but other than that we had no new discoveries in infestation since 2016.

What we suspect, based on some other research projects that shows that spiny water fleas have a really low detectability, like they can be kind of occurring in the background or evading traditional monitoring methods for a long time.

So we think that they are probably in a lot more lakes.

We have connected water bodies where a population hasn't been documented, but it's downstream from a confirmed infestation.

So the DNR considers it infested.

There are currently 67 listed infested water bodies in Minnesota.

They live and reproduce in lakes.

They can be in larger rivers.

I believe that they are in the Rainy River.

They don't really live and reside in a creek.

There are a number of infested lakes in the Arrowhead region and they're really in some of the most popular northern Minnesota fishing lakes.

Some of those really high profile lakes that are very popular for fishing.

And that kind of makes it even scarier because we have a lot of people coming and going from those lakes to fish.

And our research shows that spiny water fleas spread on fishing gear, stopping the spread is actually pretty easy.

It's just a matter of, you know, following that clean drain dry mantra.

And with spiny water flea, dry is the really key element because they do desiccate and die quickly.

And so we tell people you wanna like leave your fishing gear out and for out in the sun for at least a day before you're moving and then wiping down your monofilament.

The fishing pole eyelets is really important 'cause as you are dragging your line through the water, either reeling it in or particularly if you're using a down rigger, spiny water fleas will, they'll catch their tail spine on the fishing line and then more and more sort of catch on each other.

What that will look like is you'll just see sort of this weird gelatinous glob.

You know, it might look like any other sort of lake goop that you get on your fishing line.

But if you look closely this, it could be spiny water flea, you should be brushing that off or wiping it off with a towel.

And the other thing is really making sure all your residual water is cleaned out with hot water or fully dried.

So things like bait buckets, bilges, live wells, those are high risk areas 'cause spiny water fleas could survive in a very small amount of residual water.

If you go to a lake and if you know that spiny water fleas are there, hopefully you know we can improve the signage.

We can inform the boat inspectors and and remind people that cleaning their fishing gear is really important at this site.

We have chemicals that can kill zooplankton.

The problem is we don't have any chemicals that are spiny water flea specific.

So a chemical treatment using the available formulations would kill all the zooplankton, which is sort of a non-starter.

In really dense situations, you could have up to a hundred spiny water fleas in a cubic meter of water and you know, methods that would hypothetically be developed that could capture them.

The problem is making that species specific.

You would risk, you know, filtering out or sucking up so many native phytoplankton and zooplankton that you could do potentially a lot more harm than good.

It's a big challenge.

I could see potential genetic methods sometime long into the future being an option, but, but we haven't even done any genome work on spiny water fleas, so it's a ways out.

I think we should have some hope that research advances might give us some solutions to control them just 'cause we don't have anything in our back pocket right now, you know, doesn't mean that limiting the spread right now isn't super important.

I mean that's, that's always priority number one is to prevent future spread