Restoring to zero

Banff National Park

Aerial view of Upper, middle and lower Devon Lakes
© C. Pacas, Parks Canada

When thousands of brook trout (Salvalinus fontinalis) were stocked into Banff National Park's Devon Lakes in the 1960s, the hope was to lure anglers with the new stock. Who could foresee that the brook trout would begin to change the ecosystem at its most basic level and migrate into the surrounding rivers, crowding out native species such as the bull trout (Salvelinus confluentus) .

Tough competition

Brook trout have changed the lakes by feeding on certain invertebrate species that were not eaten by other predators. As they began to move out of the lakes, located in the northwest corner of the park, they also began out-competing native species for food and habitat.

"Brook trout operate differently from bull trout," says Charlie Pacas, aquatic specialist with the Banff field unit. "They mature at a younger age, so that when they move into the system, they're producing a lot more progeny in the time it takes the bull trout to get to the same stage." That raises concerns about what's called hybridization, or the potential loss of native bull trout genes when the two species interbreed. The bull trout has been listed as a species of special concern in Alberta.

Parks staff helps recovery

For several years, Banff staff have been working to ease the threat posed to the bull trout and its habitat by removing brook trout from the Devon Lakes and, ultimately, the Upper Clearwater River .

Since 1915, nearly 40 million non-native fish and eggs have been released into Banff National Park's watersheds. In 2002, a team of Aquatic Specialists began removing non-native Brook trout from Banff's Devon Lakes.

Restoring to Zero


Since 1915, nearly 40 million non-native fish and eggs have been released into Banff National Park's watersheds. They have significantly altered aquatic ecosystems. In 2002, a team of Aquatic Specialists began removing non-native Brook trout from Banff's Devon Lakes. The Devon Lakes are in the most remote region of Banff National Park. The fish were never supposed to be here.

Restoring to Zero.

All the parks in the mountains particularly had non-native fish stocked.

Fish in these lakes provided opportunities for people to come up to an incredible alpine environment and come fishing.

No one really realized the impact that the stocking would have.

Art Laurenson - Resource Conservation Specialist, Banff National Park Putting trout in these lakes is like putting a pyrana in your fishtank.

It's weird that people would put fish into lakes where they don't belong.

Monika Vittnova, Devon Lakes Restoration Field Technician The Brook trout eventually outcompeted the cutthroat trout and became the only species of fish in the two lakes.

And what happens is that fish do end up swimming downstream and so these fish started moving all the way through the system, populating the Clearwater river system.

The last lakes that were stocked in Banff were in 1988 and they would have been roadside-type lakes.

In about 1972, I think the warning signs were being read by many of the fisheries biologists at that time.

They realized that it was time to stop.

Charlie Pacas, Banff National Park Aquatic specialist It's like any landscape or ecosystem in the world that suffers from introduced species, it changes.

We've done restoration for years in parks and it just seems so much more natural on a terrestrial level because we as humans relate a lot better to that, but if you walked into one of these parks and you saw gazelles and zebras running around, you'd be al And you walk in here and you look in the aquatic systems and it's pretty much what you've got.

You've got top predators that aren't supposed to be there.

And it dramatcially changes the ecosystem. And because we're terrestrial beings, we don't really see that as a problem.

Barb Johnson - Waterton Lakes National Park We're hoping to try and restore a lot of the aquatic systems across the Mountain Parks - across parks in general - to their historically natural state.

We've had close to 2 km of gill nets in the lakes, fishing initially just through the summertimes in 2002 to 2005 and then we put nets in and they just stayed in the water continuously.

I'm pretty confident that we've eradicated all of the fish in the lake.

The thing about it is you look at these lakes and you think 1547 fish have been removed from the lakes since 2002.

There are only two ways that people say, if you look at the literature, that you can actually get rid of fish successfully.

One of them is through piscicides - or fish toxins.

Our original plan at the Devon Lakes was to deploy a fish toxin called Rotenone into the headwaters of the Clearwater.

By deploying this we would eliminate the last of the fish that were found in the river.

We decided not to use it even though the Rotenone is pretty much selective for fish, it does also impact the invertebrates that are found in the river and we were concerned that they may not return back to reference levels or back to their historical conditions in a short period of time.

And the other way they say to be able to successfully get rid of fish is dewatering.

We're putting in aquadams at the outlets of the upper Devon Lake and the middle Devon Lake.

The reason that we're doing that is that we're trying to stem the amount of water leaving theses lakes.

With the dams going across, basically stopping the flows will reduce the amount of water in the Clearwater river, which will give us an opportunity to get into those remaining aproximately 4 km of river and electrofish the remaining Brooktrout out of the stream.

We ended up putting in an aquadam and initially we got it filled up to about the 5 foot level, which was max and then all of a sudden the aquadam deflated.

They provided us with another aquadam - they flew it in the next morning. And we got it filled up by quarter to 10 and… It's hooped. It blew exactly around the same height as the other one.

What do they think the problem was?

Well its plastic is just weak. Weakness in the plastic.

That's all she wrote?

That's all she wrote. So today's going to be a cleanup day and we won't be continuing on with the dam.

What's going to happen with the rest of the project?

It'll still continue. We'll do it no matter what, but this was supposed to be the thing that would help out at the other end of the electrofishing.

Adios. See ya Frank. Thanks Frank.

Devon Lakes Tent Camp - 80 kilometers north of the Banff townsite We've broken the river off into 100m reaches putting in block nets at every 100m.

The fence essentially stops any kind of mevement or fish passage through or within the stream and the pvc is weighted down so there's no way that fish can actually swim underneath it.

We've split our electrofishers into four groups of two. You electrofish a reach twice if you don't catch fish.

If catch a fish, then you go back in and you electrofish until you do two successive passes without catching any fish.

At about the 4 km mark, there's a barrier waterfall, so fish can actually flow over the barrier waterfall but they can't make it back.

We'll be going right up to just below the barrier right at the outlet of the lower Devon Lake.

In about 9 or 10 days time we'll have removed all of the fish there.

Hey I'm Alex and I'm Jimmy: and together we're the Brook Trout task force. And we're going electrofishing. That's right!

140 days of electro-fishing since 2002 3616 fish caught There's always a halo over Charlie.

…Devon Lakes portable Devon Lakes, good morning.

How are you folks today?

I think everybody's doing good. We've got a little bit of snow falling now.

We're going to be working on the river and we're all back at the same location tonight.

We're kind of hoping for a little bit better weather.

So, lousy day. So we've had to rethink how we're going to get today done.

I'm thinking that we'll use the weather day to help Art, Monika and Ray out initially in the morning to move block nets.

I think it's probably snowed almost every year that we've been here.

In fact I can't recall a time where we haven't had snow. On some occassions we've had up to a meter of snow.

Having a good day?

Great day. Last day of summer, it's great. Best weather. Ever.

Well guess what? We're almost done.

We've come up to the base of the Lower Devon Lake, so the outlet of the Lower Devon Lake is probably about 40 m up.

We have a barrier waterfall here, so fish can't make it upstream from the barrier waterfall.

We've fish right to this point. There is still three other teams on the river, but they are probably about 10 - 15 minutes away from being done.

And so far, that is the number of Brookies that we have got, so ...

How does it feel to be done?

Excellent. You know, satisfying, we're happy.

We're done!

Let's go have lunch.

Not everything worked out as well as we hoped, but we put in 130,000 seconds of electrofishing effort into the creek and we didn't catch any fish, so with last last year's capture of 1 fish and zero this year, I'm feeling pretty confident that we've taken care of all the fish in the upper clearwater.

One of the biggest concerns we have as biologists or people in general is climate change.

That's going to be a huge stress on our natural systems.

Any creatures that have evolved over eons to survive in a system with all the different parts.

If there's something that can survive and adapt in time to still be able to be there, with a stressor as big as climate change or others, it's probably the native community of plants and animals that was there originally.

I think visitors to this area probably would expect that this area is in a very pristine-type state.

I'm not sure whether that's just a feeling that people have that you know, they feel that it feels prestine here, it does not look like it's been touched; and you know we have been able to bring some of it back to that state.

This isn't a quick fix. It's something that you have to learn the system intricately.

Charlie's been here since 2001 and knows this place inside out.

And if you do want to fix something you do need to know as much as you possibly can about the system before you go tinkering.

One of the things I take back is, to go and learn your systems and then decide what the best way is to try to tackle what the challenges are and also, that it can be done.

I think its a pretty important message to take back is "Dont give up".

It is a huge challenge, especially when there is complexeties like tributaries and more than one lake and when the systems are complex like this, but it still can be done.

We say that national parks is kind of the last bastion of wilderness and natural protected areas in Canada.

If there's somewhere where things should be the way they were before we meddled them up, perhaps this is where that is. And this is one place where said this is our policy; this is what we are going to do here to the best of our ability.

How does it feel to be leaving today and going away from this, probably never coming back in the same way that you've been coming here?

It feels a little sad. But I feel quite happy that we did it. So… The invertebrate population is slaready rebounding to a more natural state as a result of the brook trout removal.

Downstream of the restoration site, non-native fish species have mixed with native Bull trout.

In 2010, Charlie and his crew returned one last time and caught no fish.

Downstream, they caught over 100 non-native fish in an afternoon.

To be continued… Okay, I want your head right in here. Right about there and that's where you go: Zero. Zero fish!

No fish I didn't see a fish, smell a fish or catch a fish. Zero fish Been skunked. Haven't seen a fish all week. Zero.

No fish!

Zero fish.

Nar fish in the brook Raymond, nar fish.

Not something I usually brag about, but got skunked. No fish.

It's mighty poor fishing around here, I'll tell ya.

No fish, no kill. Go Vegetarians!

Zero fish.

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