In the Arctic, rivers often freeze all the way to the bottom each winter leaving fish with limited habitat where they can survive.
Return to Wildlife, Fish, and Habitats >> Fish and Aquatic Ecology
The number of fish living in Alaska’s Arctic rivers is thought to be capped by the availability of freshwater that does not freeze as ice creating overwintering habitat. This project is specifically focused on identifying places where young Dolly Varden char (Salvelinus malma; also called Arctic char or Iqalukpik) overwinter. Large springs in the Brooks Range are key spawning and overwintering habitat for adult char, but the smaller, younger fish may need to avoid these areas so that hungry adults do not eat them. At the same time, char cannot survive in the ocean’s cold winter temperatures. Thus, we expect that young fish seek out deeper pools or areas with small springs in the lower reaches of the river that provide pockets of overwintering habitat separated by long stretches where the river is frozen to the bottom. We will visit areas that might provide pockets of overwinter habitat in the Canning River in late winter (April) to record fish presence/absence with minnow traps, small mesh nets, hook and line sampling, and an underwater video camera. By identifying the specific places where young Dolly Varden char overwinter, managers will have more information on locations important to the population of Dolly Varden char in making decisions on human activities in and around the river.
All photo credits below: Randy J. Brown, USFWS. Public domain.
Below are other science projects associated with this project.
Fish and Aquatic Ecology
Condition of Forage Fish in Prince William Sound During the Marine Heatwave
Arctic Lake Food Webs
Ecosystem Shifts in Arctic Seas
Lake Trout Biochronologies as Long-term Climate and Productivity Indicators in Alaska Lake Ecosystems
Primary Production Sources and Bottom-up Limitations in Nearshore Ecosystems
Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Effect of Elodea spp. on Fish Performance Mediated Through Food Web Interactions
Sockeye Salmon Migrating at the Northern Edge of Their Distribution
Nearshore Fish Surveys in the Beaufort Sea
Assessing heat stress in migrating Yukon River Chinook Salmon
- Overview
In the Arctic, rivers often freeze all the way to the bottom each winter leaving fish with limited habitat where they can survive.
Return to Wildlife, Fish, and Habitats >> Fish and Aquatic Ecology
The number of fish living in Alaska’s Arctic rivers is thought to be capped by the availability of freshwater that does not freeze as ice creating overwintering habitat. This project is specifically focused on identifying places where young Dolly Varden char (Salvelinus malma; also called Arctic char or Iqalukpik) overwinter. Large springs in the Brooks Range are key spawning and overwintering habitat for adult char, but the smaller, younger fish may need to avoid these areas so that hungry adults do not eat them. At the same time, char cannot survive in the ocean’s cold winter temperatures. Thus, we expect that young fish seek out deeper pools or areas with small springs in the lower reaches of the river that provide pockets of overwintering habitat separated by long stretches where the river is frozen to the bottom. We will visit areas that might provide pockets of overwinter habitat in the Canning River in late winter (April) to record fish presence/absence with minnow traps, small mesh nets, hook and line sampling, and an underwater video camera. By identifying the specific places where young Dolly Varden char overwinter, managers will have more information on locations important to the population of Dolly Varden char in making decisions on human activities in and around the river.
In the Arctic, rivers are often thought to freeze completely during winter. Since fish need liquid water to survive, there are few places where they can live. Fish usually inhabit deep river channels and areas where springwater enters a stream. However, this video shows that winter habitat occurs in places we didn't expect, below the ice in the delta of a shallow river. Vanessa von Biela, USGS (Public domain.) All photo credits below: Randy J. Brown, USFWS. Public domain.
Sources/Usage: Public Domain.Canning River with Brooks Range in the background.
Sources/Usage: Public Domain.Michael Carey and Vanessa von Biela on the Canning River.
Sources/Usage: Public Domain.Canning River with bars.
Sources/Usage: Public Domain.Canning River with bars.
Sources/Usage: Public Domain.Vanessa von Biela with cut bank at Canning River.
Sources/Usage: Public Domain.Hole in the ice from an auger.
Sources/Usage: Public Domain.Lowering minnow trap to fish.
Sources/Usage: Public Domain.Minnow trap in icehole. - Science
Below are other science projects associated with this project.
Fish and Aquatic Ecology
Fish and aquatic habitats in Alaska support important commercial, sport, and subsistence fisheries and provide forage fish that support wildlife populations. The USGS Alaska Science Center conducts interdisciplinary research to inform local, state, federal, and international policy makers regarding conservation of fish, aquatic species, and their habitats. We work collaboratively with hydrologists...Condition of Forage Fish in Prince William Sound During the Marine Heatwave
Changes in the body condition of a key forage fish species, Pacific sand lance (Ammodytes personatus), are examined to understand how energy transfer to predators may have been disrupted during the recent marine heatwave in the North Pacific (late 2013 to mid 2016).Arctic Lake Food Webs
From 2011 to 2013 we investigated freshwater food webs of Arctic Coastal Plain lakes in Alaska to improve our understanding how Arctic freshwater food webs may respond to landscape change the warmer, drier future.Ecosystem Shifts in Arctic Seas
In addition to the direct effects of sea ice loss on walrus (Odobenus rosmarus divergens) and polar bears (Ursus maritimus) that use ice as a platform, the decline of Arctic sea ice is predicted to promote a fundamental ecosystem shift from benthic animals that forage on the sea floor to pelagic animals that forage near the sea surface.Lake Trout Biochronologies as Long-term Climate and Productivity Indicators in Alaska Lake Ecosystems
High latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments.Primary Production Sources and Bottom-up Limitations in Nearshore Ecosystems
Kelp forests are among the world’s most productive habitats, but recent evidence suggests that production is highly variable.Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Permafrost thaw is leading to a myriad of changes in physical and chemical conditions throughout the Arctic.Effect of Elodea spp. on Fish Performance Mediated Through Food Web Interactions
The potential for invasive species introductions in Arctic and Subarctic ecosystems is growing as climate change manifests and human activity increases in high latitudes.Sockeye Salmon Migrating at the Northern Edge of Their Distribution
The physiological challenge for anadromous fish to migrate upriver to spawn and complete their life cycle is influenced by river temperature.Nearshore Fish Surveys in the Beaufort Sea
Nearshore systems provide habitat to a unique community of marine and diadromous (lives in both fresh and saltwater) fish and support high fish abundance.Assessing heat stress in migrating Yukon River Chinook Salmon
We will examine evidence of heat stress in Yukon River Chinook salmon (Oncorhynchus tshawytscha) using heat shock proteins and gene expression. - Multimedia