Anglers Competing With Cormorants

  • The cormorant population is booming in the region, and some anglers say they're competing too hard with the birds for fish. (Photo courtesy of Steve Mortensen, Leech Lake Band of Ojibwe)

Anglers around the Great Lakes are eager for a summer of fishing. Everyone wants to catch the big one. But they’re getting some competition. It comes in the form of the double-crested cormorant. The big black birds with long necks are fish eaters. Cormorants were nearly wiped out by the now-banned pesticide, DDT, in the 1970’s. But now cormorants are back in big numbers. Some anglers feel there are too many cormorants now. And they say the birds are eating too many fish. The Great Lakes Radio Consortium’s Stephanie Hemphill reports on one experimental effort to control cormorants:

Transcript

Anglers around the Great Lakes are eager for a summer of fishing. Everyone wants to
catch the big one, but they’re getting some competition. It comes in the form of the
double-crested cormorant. The big black birds with long necks are fish eaters.
Cormorants were nearly wiped out by the now-banned pesticide, DDT, in the 1970’s. But
now cormorants are back in big numbers. Some anglers feel there are too many
cormorants now, and they say the birds are eating too many fish. The Great Lakes Radio
Consortium’s Stephanie Hemphill reports on one experimental effort to control
cormorants:


(sound of waves)


Robin Whaley often fishes here on Knife River. It’s the biggest spawning ground for
rainbow trout on the north shore of Lake Superior. But today she’s watching the
cormorants on Knife Island, a quarter-mile offshore.


The cormorant population is booming. About a hundred cormorants lived on the island
last year.


“I guess they’re just coming up into this area in the last few years and becoming a
problem, for degrading habitat and for eating little fish.”


Cormorants are native to this area, but they haven’t been around much in the last few
decades, because of poisoning from the pesticide DDT.


The Minnesota Department of Natural Resources stocks rainbow trout here. This year
they put 40,000 young fish into the river. Anglers like Robin Whaley hope the little fish
will grow big enough for them to catch someday.


The little fish face a lot of predators and hazards and the cormorants are one more threat.
Some people would like to reduce that threat. It’s illegal to kill cormorants. They’re
protected by law because they’re a migratory bird.


But a new federal rule says if they’re threatening a resource, people can fight back in a
different way.


Bill Paul runs the Agriculture Department’s Wildlife Services Program in Minnesota. He
sent workers onto Knife Island to try to keep the cormorants from nesting. Their methods
are experimental – but they’re pretty basic.


“We put up some flapping tarps in wind, a couple of yellow raincoat scarecrows, we also
put up ten flashing highway barricade lights, we also have a light siren device out there
that goes during the night.”


The workers also used special firecrackers shot by guns at passing birds to scare them
away.


They did this for two weeks during the cormorants’ nesting season. Bill Paul says even
with all that noise and commotion it wasn’t easy to scare them away.


“They seem to be fairly smart birds and real persistent at coming back to Knife Island.
So we’re uncertain yet whether our activities are actually going to keep them off there
long-term.”


As part of their study, researchers had permission to kill 25 cormorants to find out what
they’d been eating. They wanted to see how much of a threat the birds were to game fish
like the rainbow trout.


They found fish in the cormorants’ stomachs all right. But not the kind most people like
to catch and eat.


Don Schreiner supervises the Lake Superior fishery for the Minnesota DNR. He says
he’d need more than just a few samples to really know what the birds are eating.


“My guess is that cormorants are opportunists and if there’s a small silver fish out there
and he’s just hanging out and the cormorant has that available to eat, he’ll eat it. The
question becomes, is this a significant part of the population that they’re consuming, or
isn’t it?”


Despite the concerns of some anglers, researchers have been studying cormorants for
years, and so far they haven’t been able to prove the birds are harming wild fish
populations.


John Pastor is an ecologist at the University of Minnesota Duluth. He says the study at
Knife River won’t prove anything useful either.


He says it ignores the bigger picture. Pastor says you can’t just look at one predator and
come to any firm conclusions. There could be lots of reasons why there aren’t many
steelhead, or rainbow trout.


“Changes in land use. All the adult steelhead out there eating the young of the year
steelhead. Maybe it’s some pollutant in the lake. You never know. But it’s easy to fix on
the predator as the problem, because people see a cormorant dive down and come up with
a fish, and they say to themselves, I could have caught that fish.”


Pastor says even if the cormorants are eating lots of young rainbow trout, it doesn’t
necessarily mean the birds are hurting the overall trout population.


And even for an angler like Robin Whaley, the concern about the trout is mixed with a
feeling of respect for the cormorant.


“I admire the bird very much, but human beings, we’re in the business of controlling
habitats and populations, and this is just another case of that.”


For many anglers, the ultimate question in this competition between predators is simple.
It’s about who gets the trout – cormorants or humans.


For the Great Lakes Radio Consortium, I’m Stephanie Hemphill.

Related Links

Brighter Future for Native Trout

Anglers in Lake Superior are looking forward to the return of the coaster brook trout. The native trout was fished nearly to extinction in the early 1900s. New efforts to help the remaining populations rebound are attracting the interest of fisheries managers around the Great Lakes. The Great Lakes Radio Consortium’s Stephanie Hemphill has the story:

Transcript

Anglers in Lake Superior are looking forward to the return of the coaster brook trout. The native trout was fished nearly to extinction in the early 1900s. New efforts to help the remaining populations rebound are attracting the interest of fisheries managers around the Great Lakes. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:


The French River tumbles into Lake Superior about 15 miles from Duluth. It’s a popular fishing spot, and people are catching rainbow trout. Rainbows are not native to Lake Superior. The Minnesota Department of Natural Resources stocks them from the fish hatchery across the road.


People used to catch coaster brook trout here, but
there aren’t many of the fish around anymore.


“I haven’t seen one of those in years.”


“There aren’t any coaster brook trout. You’re dreaming.”


“‘You very seldom get them, but when you do they’re nice.’ Hemphill: ‘Why are they nice?’  ‘They’re so nice and clean, the colors are so beautiful.’ Hemphill: ‘Are they good eating?’ ‘Oh-h-h, there isn’t any better.'”


For a freshwater fish, coasters are colorful. Their sides are sprinkled with bright red dots. Their fins are edged with a bright white line. When they spawn, their bellies turn iridescent orange.


They hatch in rivers, and then swim downstream to grow up in the lake. They return to the river to spawn.


There used to be lots of coasters around Lake Superior, and in northern Lake Michigan and Lake Huron. They were a popular sport fish. In the 1850s, people came from all over to catch them. By the early 1900s coasters had practically disappeared.


Don Schreiner is the Department of Natural Resources fisheries supervisor in this part of Minnesota. He says coasters are fairly easy to catch. And that’s why they almost disappeared.


“There were no roads up here, people came in by boat, they came in by train. There’s accounts of people standing on the shore and on the riverbank and catching hundreds of brook trout.”


After the fishermen, lumberjacks came. They cut down the big trees that shaded the streams. They floated timber down the rivers, eroding the banks. Now these rivers are much more susceptible to flooding and sedimentation. The coaster brook trout need a rocky bottom, not a mud bottom, to spawn.


Then the state began stocking other fish here, so anglers would have something to catch. Pacific salmon, European brown trout. They compete with the few native brook trout that still survive in Lake Superior streams.


Some people want to try to restore the native brook trout. But others like to catch the big salmon, and the feisty rainbows. Don Schreiner says the DNR has to balance those competing demands.


“I think everybody cares about coaster brook trout as long as it doesn’t cost them anything personally. If I have to give up my favorite species in favor of a coaster brook trout, I might not be willing to do that. That’s the sort of thing we see.”


Angling restrictions imposed in the last few years have helped the trout. Schreiner says it’s possible they’ll bounce back, if people leave them alone, but improving the habitat is also key. That could take 50 years.


Some groups are trying to push things along a little faster.


The Red Cliff Tribal Fish Hatchery near Bayfield Wisconsin specializes in rearing coaster brook trout. Every year a million eggs are hatched here.


“Inside this building is where we keep our adult brood stock fish.”


Greg Fischer is the hatchery manager. He says they raise some fish for a year and a half before releasing them. Workers mark these fish to keep track of them in the wild.


“We have fin clipping parties where for several days we fin-clip each one of the fish, and when we’re stocking anywhere from 50 to 80,000 of these larger fish a year, that’s a lot of marking”


Some coasters from the hatchery might find a home at Whittlesey Creek near Ashland, Wisconsin. The U.S. Fish and Wildlife Service is turning Whittlesey Creek into a refuge for coaster brook trout.


Biologist Lee Newman says it’s a promising spot for spawning. Springs seep up through the gravel bottom. That provides the eggs with a constant flow of oxygen. Newman wants to plant eggs and very young fry directly over the springs. That’s what they did on the Grand Portage Chippewa reservation in Minnesota. And Newman says it worked there.


“We’ve captured pairs of adults that were radio tagged and captured on their spawning beds, and two years later catch the exact same pair on the exact same spawning beds, indicating that they are returning precisely to their home locations.”


Newman says when the fish are very young they can imprint on the chemistry of the stream, and find their way back years later.


Biologists still have a lot of questions about how to help the coaster brook trout. But right now, at least, its future looks a little brighter. For the Great Lakes Radio Consortium, I’m Stephanie Hemphill.