(blues guitar music) - [Bret] Invasive carp are moving up the Mississippi River and knocking on Minnesota's southern door.

To track their movement and behavior, the Minnesota DNR has tagged three invasive carp, including Billy Bighead.

He was netted on the St. Croix River seven years ago and has evaded his captors ever since.

(blues guitar music) - Our tagged bighead, or we nicknamed him Billy, is a little bit of a legend at the DNR.

The fish was tagged in July of 2017, and since then we have been trying to recapture this fish.

His tag expires next February, so February of 2024.

And we have tried to throw every new piece of researched sampling at this fish that we possibly can.

Sampling's just kind of a broad term that we use to, it encompasses gill nets, commercial seines, beach seines, electro fishing, all the different things that we can do to target these fish and potentially remove these fish.

This tag goes off every 30 to 90 seconds for the last almost seven years now.

As of last spring, we had over 700,000 detections on this one fish.

One of the VPS arrays that we've had out here showed Billy just constantly hanging out in this spot for most of one winter.

So, and they're at 56 feet right there.

We need to get in closer, so I don't think he's sitting in there.

So I think we can go in there, at least start getting 'em and get a directional on 'em that way.

We'll go out there and try to net this fish and this fish just will disappear.

He'll be gone.

We won't be able to get a single detection on this fish and all of a sudden he's three miles downstream.

Had to go out and get a specialized net to sample deep water habitat because this fish would try to dive around our other nets and get down to like, 74 feet.

And it's not that the fish likes to do that, he's trying to avoid us.

Like, this fish definitely, I'm sure is laughing at us as it's watched us for the last six and a half, seven years now, try to net him again.

We always joke that he is a party fish.

'Cause you know, 4th of July comes, Memorial Day comes, that fish is tucked up tight in Anderson Bay, and as soon as we're back Monday, Tuesday, that fish is gone.

(blues guitar music) There is evidence there to suggest that these fish will associate certain activities like, such as netting, with like the sound of commercial fishermen pounding on the side of the boat, with the fact that they had surgery last time they were caught.

So they kind of have a tendency to panic in large groups and then therefore escape, and try to do everything in their power.

Or, I mean we've even had this fish hide behind trees as we're trying to detect 'em.

Of the three invasive carp that we have in Minnesota, bighead carp tend to get the biggest.

We don't have a lot of those.

Those usually come first with the invasion front and then silver carp come in after that.

And silver carp, the ones that jump.

Following these fish around, we've learn about new habitats that they like to be in and oftentimes we can sample that area where that fish actually is, and potentially remove other species, mainly silver carp.

We start by deploying the the purse seine, and we set that out using two commercial fishing boats.

And once that purse seine is completely closed up, then we can start pulling it like a traditional beach seine.

Our invasive carp program started in 2012, started with LCCMR funding and since then we've branched out and really tried to focus on new and innovative techniques.

Telemetry involves surgically implanting a hydroacoustic tag, that's about the size of your thumb, into a fish.

We just flip the fish over on a surgery cooler that's especially made.

You just cut open the fish, you carefully implant this tag, you suture the fish back up, and then you hold it in the water for a little while to make sure that it recovers adequately before you release it.

We have a whole network of receivers throughout Minnesota's waters that help us detect these individual tags.

- [Bret] The DNR has tagged almost 300 fish on the Minnesota, St. Croix, and Mississippi Rivers, including native species like muskie, sturgeon and big mouth buffalo.

- One of the key ones is paddlefish.

And we can actually watch paddlefish movement and oftentimes it's closely associated if there's invasive carp moving upstream.

The paddlefish are often moving upstream at the same time or very similar timing.

Right now in Minnesota, most of our invasive carp are centraled around anywhere from pool eight down La Crosse, all the way up to about Winona areas.

All of those fish have been moving upstream since they were introduced or accidentally introduced in the 1970s down in Arkansas.

We had a high water event in 2019.

We had a whole bunch of fish move up and we had this large capture of 50 or so in pool eight in La Crosse, - [Participant] It's a big seine haul, they got a whole pile of 'em here.

We've already pulled out five silvers and three grass carp.

- These fish continually move up with each high water event that we have.

That's what they're looking for, for not only food, but also for for reproduction, to spawn.

We do not actually have a confirmed sampling report saying that they have spawned in Minnesota.

The biggest problem with invasive carp is that where they land in the food chain, they eat the bottom, they eat algae, they eat, phytoplankton and zooplankton, so they're eating what everything else needs at some point in their life to survive.

Everyone always thinks that walleye are one of the top predators.

Well, they start out as small fry.

They can't eat minnows on day five of their existence.

They need that small phytoplankton, zooplankton to survive.

- [Bret] Agencies use several different methods to remove carp.

- [Kayla] Netting is probably the the best way, and that's what's been proven down south in high-density populations, is that commercial fishing tends to be the easiest way to remove these fish.

- [Bret] On November 30th, the DNR pulled a record 331 invasive carp from the Mississippi River's pool six, including 289 silver carp.

The capture was made possible by partnering with Wisconsin DNR staff to track tagged invasive carp.

The Minnesota DNR is also working with the U.S. Geological Survey to deploy floating gill nets and an underwater speaker system that can drive silver carp over the nets.

- [Kayla] We irritate them to the point that they jump, kind of like boat motors downstream.

- [Bret] The system was developed in Columbia, Missouri, and tested on the Mississippi last October.

Six silver and one grass carp were captured and tagged pool six and eight.

- We also do use electro fishing.

We actually take out a specialized boat that allows us to put electricity down into the water from anodes.

We can use it to not only sample fish and collect fish, we'll have two netters on the bow of the boat scooping up fish, but we can also use it to drive fish.

So we don't have to use high electricity with invasive carp all the time.

(blues guitar music) Bow fishing is one of the ways that citizens can partake in the removal of invasive carp.

Downstream of here where there's a higher-density population, it's one of the ways that people can go out and actually make a sport of it to get these things out of our system.

We don't see a lot of pressure up here for that quite yet, mostly because we don't have a high enough density population.

We had a work plan that was originally established in, I think it was 2011, to pretty much get all of our options for what to do on the table, and then we'll start analyzing that so that we find the best options for Minnesota.

So all of our partnering agencies, Fish and Wildlife Service, USGS, even Wisconsin DNR and Iowa DNR, they're all working on the same network.

We'll start comparing all the different methods, combination of methods, figure out which one's most cost effective, and then we'll actually write our action plan for Minnesota.

If we don't do anything about invasive carp, a leisurely cruise on the St. Croix, you might have to, if you go out there, you might have to put shields up like, acrylic shields on the front of your boat.

There's a lot of boats downstream that have chain link fence around their console, so that the driver of the boat doesn't get knocked outta the boat as they're driving downstream..

I mean the, these fish will break bones, they'll give you concussions, they'll do damage to your boat.

There's always going to be that opinion that the whole thing is a lost cause.

They're already here, they're gonna be established in the next, who knows how many years, who cares, right?

Well, I don't know about you, but I'm doing this for my children's children's children.

I'm doing it for yours.

Why give up on something so great that we have here in Minnesota?