ancient waters give fish life in Arctic National Wildlife Refuge

When woolly mammoths still roamed Earth, rain and snow fell on the south side of Alaska’s Brooks Range. Those same ancient waters are just now entering frozen rivers on Alaska’s North Slope via perennial springs. And they hold the key to survival for salmon-sized Dolly Varden and several other species of fish in Arctic National Wildlife Refuge.

Clockwise from top: Alaska’s Brooks Range (USFWS/Katrina Liebich); Shublik Spring emerges from a mountainside in Arctic National Wildlife Refuge before flowing across tundra and into the Canning River. It flows at the same volume and temperature (~5.5ᵒC) all year, every year. Radio carbon dating indicates this ancient water was last exposed to the atmosphere 1,200 years ago; a Canning River Dolly Varden displays his vibrant spawning colors (USFWS/Randy Brown)

Uiññiq and I squeeze into the cockpit — me next to the pilot and her in back. We have enough gear for about two weeks, a cooler of food, and pizza leftovers from my stay in Fairbanks the night before. We’re headed some 300 miles north to the Canning River. It’s wild, remote, and demarks the western boundary of the iconic Arctic Refuge as it flows north across the coastal plain.

In a couple of hours, we’re into the Canning’s birthplace: the craggy, slate-colored peaks of the Brooks Range. Dipping down along its Marsh Fork, we watch it braid out below past muskox, bears, and small groups of caribou.

Clockwise from top: Canning River from the air; caribou moving up the braids; musk ox near camp (USFWS/Katrina Liebich)

The pilot cranks on something and we descend, landing between coolers marking a makeshift runway. After quickly unloading, the previous crew of two boards and we wave goodbye. The drone of the plane’s engines are soon replaced by the sound of water moving over rocks towards sea. We load the rafts and paddle our gear across the swift current to camp.

Camp. USFWS/Katrina Liebich

In this part of Alaska, fish might not be the first thing that comes to mind. Except for the occasional stray, Pacific salmon haven’t even gained a foothold this far north. Not many fish have. Continuous permafrost hundreds of feet thick surrounds rivers that freeze solid in winter for nearly their entire length. Marine waters become too cold under sea ice for many species. Here, suitable winter habitat (liquid freshwater) for Dolly Varden and other northern fish is a rare resource in high demand.

The Canning River in winter. An open channel starting at Shublik Spring (right) provides winter habitat for fish. USFWS/Randy Brown

Uiññiq and I are here to help fisheries biologist Randy Brown better understand this tough Arctic fish. Tracking Dollies to their overwintering areas allows us to identify the perennial water sources that support these populations during a season when unfrozen freshwaters are extraordinarily rare. We know that water from perennial springs during winter provides only about 5% of water available in summer. We also know free and consistent access to and availability of these springs is the only reason this river (and others in the Refuge) support any fish at all. These same rare waters may also be called on to support oil development if the “1002 Area” of the Arctic National Wildlife Refuge is ever opened to drilling.

Randy, a long-time Alaskan, left Santa Fe for Alaska at age 19 to live off the land. He’s worked as a fish biologist for the U.S. Fish and Wildlife Service for the past two decades. He’s based out of our Fairbanks Fish and Wildlife Conservation Office. Uiññiq Ahgeak, born and raised in Barrow, Alaska, is also a Service biologist. She began her career as an Eider Journey student in 2006 and is based in our Barrow Field Office. USFWS/Katrina Liebich

As the ice melts and flowing water fills the rivers again each spring, Dolly Varden find new-found freedom to move. They migrate to sea and disperse widely throughout the nearshore waters of the Beaufort Sea. Here, they’re caught along the coast from Barrow in the west to the Canadian border in the east. They’re the primary fish species harvested in some northern communities including Kaktovik. And they’re an added bonus for visitors. People travel here from all over the world to hunt, fish, and float the North Slope’s rivers and marvel at the nation’s northernmost refuge and its unique diversity of life.

A Canning River Dolly Varden. Like salmon, Dollies are anadromous, meaning they have the relatively rare ability among fish to move between fresh and saltwater. This physiological feat gives them the best of both worlds: safe freshwater nursery habitats and a seasonal smorgasbord of nutritionally-rich marine prey. The latter helps them reach their salmon-sized proportions. Unlike salmon, Dolly Varden don’t die after spawning and must find suitable refuge to spend the winter. USFWS/John Wenburg
Fall colors frame the Canning River. USFWS/Katrina Liebich

It’s August. The leaves on miniature windswept trees are all colored up like a spawning male Dolly. Uiññiq and I are ready to get to work. Our task: help Randy catch and radio tag Dolly Varden. We have two methods available to us: hook and line and, depending on our success (or lack thereof), gillnet.

Fishing for Dolly Varden. USFWS/Katrina Liebich

The radio tags are amazing little pieces of technology that will help Randy pinpoint the location of tagged fish. They’re mostly battery, with a little bit of electronics connected to a wire transmitter. Randy can pick up their signal from the air with an antennae when he flies at ~1,200 feet elevation. A radio station downstream records tagged fish as they migrate seaward in spring and back upriver in fall to spawn and overwinter. Randy’s programmed the tags to turn off in winter while the fish are holed up around the springs. Conserving battery life will let him collect three years of migration data.

A radio tag. The radio station downstream logs tagged fish as they pass by, the date and time, and their direction of travel. USFWS/Katrina Liebich

Uiññiq has a fish on and she lands it. It’s a male Dolly Varden. Randy already has his tagging surgery center set up and ready for the patient. It consists of a tub with an anesthetic bath, a cradle with padded sides, and two buckets. One bucket delivers anesthetic in the early part of the surgery. The other delivers river water directly to the fish’s gills later in the surgery. Randy quickly transfers the fish to a tote full of water and we carry it to the surgery center. After five minutes in the anesthetic bath, it’s ready to be radio tagged.

A Dolly is prepped to receive a radio tag. USFWS/Katrina Liebich

Over the years, Randy’s tagged thousands of Dolly Varden, Bering Cisco, and other fish species. In so doing, he’s acquired a huge wealth of knowledge about the fish inhabiting the northern corners of the state. And a very particular set of skills. Because of this, he’s frequently contacted for advice and help with everything from tagging and telemetry to whitefish behavior.

He quickly preps the fish and checks that all of his tools are in place. With the patient belly up in the padded cradle, Uiññiq gently slips a clear tube carrying a continuous flow of anesthetic and water under its operculum (the firm plate that protects the gills). The first and only incision is about an inch long. Through the tiny opening, Randy places a groove director parallel to the internal organs. Then he inserts a small needle just below the pelvic fin and into the groove director to prevent puncture. With the wire transmitter slid into the needle, the needle can come out. What’s left is a wire trailing behind the fish that’s long enough to transmit a signal. Randy slips the radio tag into the space between the internal organs and the body cavity wall. After quickly placing three sutures, he carries the fish several feet to the river. The anesthetic wears off and it starts to wiggle. After a few minutes it swims off to join over 200 other tagged Dolly Varden. For the next few years they’ll tell the story about where they go and what they need to survive. Stay tuned!

Canning River Dolly Varden are tagged and released. USFWS/Katrina Liebich

Katrina Liebich is based in Anchorage, Alaska and has served in her current position as Fisheries Outreach Coordinator in Alaska for the U.S. Fish & Wildlife Service since 2010.

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