We sat down with Randy Brown (a Fish Biologist in the U.S. Fish and Wildlife Service’s Fairbank Fish and Wildlife Conservation Office) to talk about North Slope Dolly Varden.
Randy, we know you’re based in Fairbanks and work the northern parts of Alaska. How do Dolly Varden fit into the fish community there, especially on the North Slope?
Dolly Varden are present in a lot of different river systems up here. They’re in the Yukon River but tend to get over-shadowed by salmon and whitefish. And a lot of the upper drainage Dolly Varden there are resident fish [they don’t migrate to sea] so they don’t grow very big. But up on the North Slope of Alaska, where there aren’t really any spawning populations of salmon, they’re the biggest of the salmonids.
In the eastern Arctic, Dolly Varden are able to eek out a living because they overwinter in rapid streams that flow really strongly during the summer and are rocky and fast. The whitefishes are not wild about that sort of a habitat. But Dollies do well in it, and they overwinter in perennial springs that create little oases of flowing water when the rivers themselves freeze completely in winter. The water that feeds the little springs comes from south of the Brooks Range from a large limestone region that’s really porous. It flows for hundreds or thousands of years underground and emerges in those northern rivers to create that unfrozen winter habitat. That’s what the Dolly Varden live in and Arctic Grayling live there with them.
As you get a little over to the west of that region and over to the Mackenzie River you also have some other species — like Burbot or Round Whitefish.
In terms of those big Dollies, they occur where the freshwater food choices aren’t so great but the ocean has abundant food. Let’s talk about that.
The Dolly Varden are big there — six pounds is not unusual and they get to be as heavy as 10 pounds. In basic form they look a lot like a salmon but they’re a char. And, as char, they’re adapted to some different life options. Anadromy is a strategy where the spawning takes place in freshwater and, at some point in life, the juveniles migrate out to sea to feed and then migrate back to spawn. Anadromous Dolly Varden usually have to make several trips to sea and back into freshwater before they become mature enough to spawn.
On the North Slope where the environment is so severe, the life history of these Dolly Varden is that they spawn in those perennial springs usually late summer or fall or early winter. It can vary a little bit, but those eggs incubate through the winter and they hatch the next spring. The young Dollies occupy those rivers for a few years — anywhere from 2–5 years. At some point they get triggered to migrate to sea and become anadromous. The reason they do this is because the food resources out in the ocean are so huge compared to those in the freshwater rivers.
Once they begin migrating to sea they don’t eat anymore in freshwater. It’s a really crazy phenomenon. Studies show the big adults are just not feeding in freshwater. Every once in a while one has an invertebrate in its stomach, but their primary feeding is for about a month or two when they’re out at sea during the summers.
The reason they don’t stay out at sea, like a salmon, is because the temperature of the Beaufort Sea and Arctic Ocean under ice is about -1.7 degrees Celsius. It’s too cold for them to be there — their body fluids cannot tolerate that. None of the salmonids can. And that’s one of the reasons why the salmon aren’t up there. Salmon don’t go back into freshwater on a yearly basis. They stay out in the ocean. And so they have to be down in warmer seas where they spend the winters. Whereas the Dolly Varden have this strategy where they migrate back into the freshwater for winter and then migrate back out to sea and they feed like crazy out there. Then they migrate back in the mid to late summer to spawn and overwinter in freshwater. (read more: Fish Fasts 20 Months for Chance at Love).
One of the curious things is that there are a few isolated places where Dolly Varden were able to get into during some point in history and they’ve developed into dwarf forms that are only be 4–6 inches long at maturity. They still have parr marks that only juveniles typically have. These dwarf forms are kind of like Desert Pupfish where you have these unique little isolated populations. One of the famous dwarf populations lives in Shublik Spring up on the North Slope.
It’s a spring that comes straight out of the ground at full flow and is about 5.5 degrees Celsius. It flows for less than a mile and then goes over a big waterfall into the Canning River. It flows like that all the time — summer and winter. These little Dolly Varden got up there and that whole population lives in that tiny stretch of stream. The other population of dwarf Dolly Varden is over in the Sadlerochit River. There’s a spring there that flows really warm — it’s always 13 degrees Celsius. It flows for quite a long ways before it gets cold enough to go into these big aufeis fields and then freezes as it flows along. The Jago is a good size river, but it doesn’t have a perennial spring that’ll support overwintering fish. So it doesn’t have any anadromous Dollies (read more: Ancient Waters Give Fish Life).
Arctic National Wildlife Refuge is a pretty special place. People don’t tend to think about the fish maybe as much as the caribou or the crazy diversity of birds that come here from all over the world to breed. If somebody wanted to go fish in Arctic Refuge, is that possible? Can you do a float? What do you need to think about to plan a trip like that?
If you’re going on the north side of Arctic Refuge you’d have to access it with an air carrier. There are a number of them in Fairbanks and Fort Yukon and Cold Foot that actually make a business of flying people into places like the Canning River, the Hula Hula, the Jago, or the Kongakut.
For someone who hasn’t seen Arctic Refuge and the area north of the Brooks Range, what’s it like?
It’s absolutely beautiful. There are a few cottonwood groves where the perennial springs are, but there aren’t forests in the typical sense. For the most part you have short little willows. You have open tundra landscapes and the great big rugged mountains of the Brooks Range.
A lot of the rivers have these big braided sections. The wild river courses come from break up in the spring when you have sheet-like masses of aufeis — layered ice that forms from the constantly flowing perennial spring water.
Those braids allow airplanes with big tires like Beavers or Super Cubs to have suitable gravely areas to land. They routinely land in the upper reaches of these rivers and drop people off with rafts so they can float downriver and then get picked up. With the Hula Hula River, some people raft all the way out to the Beaufort Sea and get picked up by boat from Kaktovik. There are a number of different ways to do it. It’s an absolutely spectacular landscape. Usually there are caribou around during the summer and there might be a grizzly bear or sheep up on the mountains. It’s wonderful.
Where can you find Dollies on the North Slope of Alaska?
Dolly Varden occupy a number of different streams up there. They’re up in the Anaktuvuk River flowing into the Coleville and down to the mouth. And that’s the farthest west we know that they exist. They have a big population there. And then you have the Sagavanirktok River that flows into the Beaufort sea in Prudhoe Bay. The Sagavanirktok is the only place with road accessible fishing — all the other streams require air travel.
The Canning River [the western boundary of Arctic Refuge] has a large population of Dolly Varden. The Hula Hula River has four big springs that support overwintering Dolly Varden and the Aichilik River, which is farther to the east, has one big spring supporting Dolly Varden. There are a few other streams that have smaller populations but they’re not really floated very much by adventurers.
The Kongakut River is probably the most ideal river if someone wanted to go fish Dolly Varden up there because it’s really clear. The Hula Hula on the other hand has glaciers that flow into it, so it stays relatively turbid—the Dollies are there but you can’t see them. The Canning river also has some glaciers in the upper drainage that feed some turbidity into it so it doesn’t get all-the-way clear like the Kongakut. If the Kongakut is raging from a storm it becomes turbid and but it’s usually pretty crystal clear and you can see these big Dolly Varden that congregate to spawn. They’re really brilliantly colored when they’re in spawning condition. They’re bright orange or red and they’ve got these big spots on them and they can be more than two feet long and weigh 5–10 pounds in that condition. They gather in these clusters and it’s like a pastel painting.
Is that coloration where they get their name from?
Yeah its actually from a book — Barnaby Rudge. Dolly Varden was a character in that book and she’s got these brightly colored jackets.
There’s a lot of individual variation around Alaska. Some fish get really bright almost pink or bright orange across their whole lower part of their body. Their light spots get bright orange with a light halo around them.
How do you tell the different char species apart?
The char are part of a group that have light spots on a dark background whereas the trout and salmon have dark spots on a lighter background so they can be recognized as different by that feature.
If you’re in Alaska you have four options: Dolly Varden, Arctic Char, Lake Trout, and anadromous Brook Trout down in Southeast Alaska.
Lake Trout mostly live in lakes but they aren’t completely confined to them. Sometimes they’ll go out through an a lake outlet stream and can be caught in the rivers at times. They get really old — 40 to 50 years or older.
Arctic char are really interesting. In Alaska they’re generally not anadromous. They look very similar to a Dolly Varden. I know in places where they both occur most people cannot tell the difference. There are morphological differences that make them unique. On the North Slope and in the Brooks Range area, Arctic Char are really confined to lakes and can get really old like Lake Trout. The Dolly Varden that are anadromous rarely get over 10 years old. They experience extreme mortality when they go to sea.
If you go to a lake and you catch a big char that isn’t a Lake Trout it’s an Arctic Char. Whereas if you’re in one of these rapid flowing rivers and you catch a big char it’s a Dolly Varden.
The males get a lower jaw when they’re in spawning condition that sticks way out in front of their upper jaw and curls up over the tip of their nose. It’s pretty crazy! The salmon on the other hand tend to have an upper jaw that curls around their lower jaw.
They appear to be very similar in form and behavior to salmon and trout — are they a good sport fish?
They are a great sportfish! These big Dolly Varden that come in from the sea are an exciting catch for anyone who hooks them. They fight like crazy. They jump in the air. They make runs up and down. They’re really a tough fish and they’re powerful.
There used to be a bounty on Dolly Varden in the early days. You’d get a payment if you turned in their tails because people were concerned Dollies were eating young trout and salmon.
That bounty on their tails was in Bristol Bay where there was concern in the sockeye fishery that the Dollies were eating too many Sockeye Salmon eggs. The bounty ultimately ended because an analysis of the tails they found that a lot of people were taking trout and sockeye tails and turning them in. The bottom line is Dolly Varden will eat eggs that are loose and drifting downriver but those are not going to live anyway. Dollies aren’t digging up redds to eat eggs.
So would salmon eggs be a good lure choice?
They’ll hit flies. They don’t eat when they’re in freshwater. There are different locations where they might not go to sea, like the Lake Iliamna area. There, they do eat in freshwater so they’re a little different than the North Slope Dollies. But the big anadromous Dolly Varden tend not to eat — it’s not an absolute like with salmon, who can’t eat due to their digestive system atrophying when they return to spawn.
But they all have that mechanism where they want to strike at things. Just like when you’re out fishing for Cohos or Sockeyes or Chinook — they’ll strike a lure, but they won’t actually be able to eat it. But it’s like an instinctive reaction. With the Dollies, there’s a debate if they won’t eat or they just can’t find enough to eat in freshwater. Because they’re so big and the rivers that they occupy aren’t so bountiful that they would have a lot to eat at that size. As juveniles they’ve got enough to eat but as adults it doesn’t work for them. But they will strike.
If someone were to fish for them, they’d want to get something maybe big and flashy — like a spinner — that might work well to entice a strike?
Yes. Streamer flies work. I’m not that much of a fly fisherman now. Once I started fishing gill nets and that kind of spoiled me. And mostly with work projects it’s been a catching efficiency issue and metal lures work well.
Fascinating stuff. Thank you so much, Randy. To all you fish fans out there: we hope you get out and enjoy All The Fish!
Thanks to our guest, Randy Brown. Interview by “Fish of the Week!” co-hosts Katrina Liebich and Guy Eroh. Compiled by Katrina Liebich, Digital Media Manager for the U.S. Fish and Wildlife Service’s External Affairs in Alaska.
In Alaska we are shared stewards of world renowned natural resources and our nation’s last true wild places. Our hope is that each generation has the opportunity to live with, live from, discover and enjoy the wildness of this awe-inspiring land and the people who love and depend on it.