Dwarf least cisco (Coregonus sardinella) were the primary diet item found in stomachs of lake trout (Salvelinus namaycush) from Nutuvukti Lake. These fish, measured at about 90 mm (3.5 in) in length, were reproductively mature.
Sarah Laske, Ph.D.
Research Interests: Landscape ecology, community ecology, aquatic food webs, and the influence of extreme climates and hydrology on fish ecology
My research focuses primarily on three areas of fisheries research: aquatic food webs, community ecology, and effects of landscape processes and scale in Arctic and subarctic species and ecosystems. The rapidly changing climate in northern ecosystems is shifting the thermal landscape where species live, eliciting a biological response to that change. I am interested in how those changes will influence aquatic systems, including their species composition or diversity, trophic structure, or function. Often, however, there is little to no baseline information available, and study must begin with questions regarding species presence or assemblage composition. By using a suite of modeling tools, I can integrate data from individual fish, communities, and the environment in order to answer questions that are relevant to fishery managers, the public, and other stakeholder groups, while also adding to ecological understanding of high latitude ecosystems and communities.
Science and Products
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...
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.
Tracing Mercury Through Lake Food Webs
Mercury concentrations in fish likely reflect different energy sources in lake food webs. Species, populations, or individuals may contain higher and variable concentrations of mercury, which may relate directly to prey mercury content, diets of fish, and fish foraging strategies.
Does fish prey influence red-throated loon productivity?
This study will evaluate the nearshore marine feeding areas of breeding adult red-throated loons and assess the response of loon reproductive success to differences in the relative abundance, composition, and nutritional content of nearshore fish communities that vary in space and time.
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.
Arctic Coastal Plain Studies
The Arctic Coastal Plain (ACP) is a large region of low-lying, lake-rich land on the North Slope of Alaska. This region is underlain by thick ground ice, which is susceptible to erosion and thaw. These physical changes are likely to alter ecosystems by changing the availability of habitats and food resources upon which wildlife depends. Our studies on the ACP aim to understand the link between...
Filter Total Items: 32
Diet items
Dwarf least cisco (Coregonus sardinella) were the primary diet item found in stomachs of lake trout (Salvelinus namaycush) from Nutuvukti Lake. These fish, measured at about 90 mm (3.5 in) in length, were reproductively mature.
Jigging for lake trout
Biologists jig for lake trout (Salvelinus namaycush) on Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Thick smoke from wildfires in the Kobuk River and Koyukuk River valleys settled over the lake for a week during field sampling in August.
Biologists jig for lake trout (Salvelinus namaycush) on Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Thick smoke from wildfires in the Kobuk River and Koyukuk River valleys settled over the lake for a week during field sampling in August.
Aquatic plants
Emergent vegetation growing in the shallow water of Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Emergent vegetation provides habitat for aquatic insects and small fishes.
Emergent vegetation growing in the shallow water of Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Emergent vegetation provides habitat for aquatic insects and small fishes.
Lake trout from Chandler Lake
A field biologist landed this large 7 kg (15 lb) lake trout (Salvelinus namaycush) on the shore of Chandler Lake, Gates of the Arctic National Park. The lake trout was collected as part of a study investigating the biomagnification of mercury through lake food webs.
A field biologist landed this large 7 kg (15 lb) lake trout (Salvelinus namaycush) on the shore of Chandler Lake, Gates of the Arctic National Park. The lake trout was collected as part of a study investigating the biomagnification of mercury through lake food webs.
Algae collection
Algae collected from rocks in the littoral zone of Chandler Lake, Gates of the Arctic National Park. Algae samples are used to establish an energy baseline for the food web, as primary producers – organisms that produce their own food through photosynthesis – algae provide food to the lake’s benthic macroinvertebrates.
Algae collected from rocks in the littoral zone of Chandler Lake, Gates of the Arctic National Park. Algae samples are used to establish an energy baseline for the food web, as primary producers – organisms that produce their own food through photosynthesis – algae provide food to the lake’s benthic macroinvertebrates.
Chandler Lake fishing
The sampling team at Chandler Lake, Gates of the Arctic National Park, walk along the shoreline to a new angling location. While treated to beautiful views, field biologists fished for lake trout (Salvelinus namaycush) as part of a study investigating the biomagnification of mercury through lake food webs.
The sampling team at Chandler Lake, Gates of the Arctic National Park, walk along the shoreline to a new angling location. While treated to beautiful views, field biologists fished for lake trout (Salvelinus namaycush) as part of a study investigating the biomagnification of mercury through lake food webs.
Chelle Lake trout collection
A biologist samples lake trout (Salvelinus namaycush) tissues. This fish, captured in Chelle Lake within Wrangell-St. Elias National Park, is part of a study investigating the biomagnification of mercury through lake food webs. Mount Drum rises above the hills to the southeast.
A biologist samples lake trout (Salvelinus namaycush) tissues. This fish, captured in Chelle Lake within Wrangell-St. Elias National Park, is part of a study investigating the biomagnification of mercury through lake food webs. Mount Drum rises above the hills to the southeast.
Lake in Wrangell St. Elias National Park
Lake in Wrangell St. Elias National Park. This is part of a study examining mercury in lake food webs.
Lake in Wrangell St. Elias National Park. This is part of a study examining mercury in lake food webs.
Round whitefish in Wrangell St. Elias National Park
Round whitefish in Wrangell St. Elias National Park. Round whitefish (Prosopium cylindraceum) were collected as part of a study examining mercury in lake food webs.
Round whitefish in Wrangell St. Elias National Park. Round whitefish (Prosopium cylindraceum) were collected as part of a study examining mercury in lake food webs.
Longnose sucker in Wrangell St. Elias National Park
Longnose sucker in Wrangell St. Elias National Park. Longnose suckers (Catostomus catostomus) were collected as part of a study examining mercury in lake food webs.
Longnose sucker in Wrangell St. Elias National Park. Longnose suckers (Catostomus catostomus) were collected as part of a study examining mercury in lake food webs.
Fishing for lake trout in Wrangell St. Elias National Park
Fishing for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) and Ashley Stanek (USGS – ASC) angle for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs.
Fishing for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) and Ashley Stanek (USGS – ASC) angle for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs.
Burbot in Wrangell St. Elias National Park
Burbot in Wrangell St. Elias National Park. Burbot (Lota lota) were collected as part of a study examining mercury in lake food webs.
Burbot in Wrangell St. Elias National Park. Burbot (Lota lota) were collected as part of a study examining mercury in lake food webs.
Fyke net in Wrangell St. Elias National Park
Fyke net in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) adjusts a fyke net installed in a lake in Wrangell St. Elias National Park. Fyke nets are used to non-lethally capture fish.
Fyke net in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) adjusts a fyke net installed in a lake in Wrangell St. Elias National Park. Fyke nets are used to non-lethally capture fish.
Arctic grayling in Wrangell St. Elias National Park
Arctic grayling (Thymallus arcticus) in Wrangell St. Elias National Park. Arctic grayling were collected as part of a study examining mercury in lake food webs.
Arctic grayling (Thymallus arcticus) in Wrangell St. Elias National Park. Arctic grayling were collected as part of a study examining mercury in lake food webs.
Lake trout sampling
Lake trout with stomach contents in Wrangell St. Elias National Park. Dorsal muscle collection and stomach content analysis are used to evaluate biomagnification of mercury in Lake trout (Salvelinus namaycush). Stomach contents visible below the fish consist primarily of slimy sculpin (Cottus cognatus).
Lake trout with stomach contents in Wrangell St. Elias National Park. Dorsal muscle collection and stomach content analysis are used to evaluate biomagnification of mercury in Lake trout (Salvelinus namaycush). Stomach contents visible below the fish consist primarily of slimy sculpin (Cottus cognatus).
Collecting benthic macroinvertebrates
Collecting benthic macroinvertebrates in Wrangell St. Elias National Park. Sarah Laske (USGS – ASC) collects benthic macroinvertebrates using a kick net in a lake in Wrangell St. Elias National Park, Alaska, as part of a study examining mercury in lake food webs.
Collecting benthic macroinvertebrates in Wrangell St. Elias National Park. Sarah Laske (USGS – ASC) collects benthic macroinvertebrates using a kick net in a lake in Wrangell St. Elias National Park, Alaska, as part of a study examining mercury in lake food webs.
Collecting zooplankton in Wrangell St. Elias National Park
Sarah Laske (USGS - ASC) collects zooplankton from a lake using a plankton net in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs. Sam Graf (NPS - LACL) angles.
Sarah Laske (USGS - ASC) collects zooplankton from a lake using a plankton net in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs. Sam Graf (NPS - LACL) angles.
Lake trout otolith section
Cross section of a lake trout (Salvelinus namaycush) otolith collected from a fish in Lake Clark National Park. Otoliths, also known as 'earstones' are hard, calcium carbonate structures located directly behind the brain of bony fishes.
Cross section of a lake trout (Salvelinus namaycush) otolith collected from a fish in Lake Clark National Park. Otoliths, also known as 'earstones' are hard, calcium carbonate structures located directly behind the brain of bony fishes.
Filtering phytoplankton from lake water
Phytoplankton is filtered from lake water for analysis of mercury content. Photo courtesy of U.S. National Park Service, Public Domain.
Phytoplankton is filtered from lake water for analysis of mercury content. Photo courtesy of U.S. National Park Service, Public Domain.
Water collection, Alaska
Biologist collects water from a lake in Lake Clark National Park. Photo courtesy of U.S. National Park Service, Public Domain.
Biologist collects water from a lake in Lake Clark National Park. Photo courtesy of U.S. National Park Service, Public Domain.
Juvenile sockeye salmon, Alaska
Juvenile sockeye salmon (Oncorhynchus nerka) captured in Lake Clark National Park as part of a study examining mercury in lake food webs.
Juvenile sockeye salmon (Oncorhynchus nerka) captured in Lake Clark National Park as part of a study examining mercury in lake food webs.
Science and Products
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...
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.
Tracing Mercury Through Lake Food Webs
Mercury concentrations in fish likely reflect different energy sources in lake food webs. Species, populations, or individuals may contain higher and variable concentrations of mercury, which may relate directly to prey mercury content, diets of fish, and fish foraging strategies.
Does fish prey influence red-throated loon productivity?
This study will evaluate the nearshore marine feeding areas of breeding adult red-throated loons and assess the response of loon reproductive success to differences in the relative abundance, composition, and nutritional content of nearshore fish communities that vary in space and time.
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.
Arctic Coastal Plain Studies
The Arctic Coastal Plain (ACP) is a large region of low-lying, lake-rich land on the North Slope of Alaska. This region is underlain by thick ground ice, which is susceptible to erosion and thaw. These physical changes are likely to alter ecosystems by changing the availability of habitats and food resources upon which wildlife depends. Our studies on the ACP aim to understand the link between...
Filter Total Items: 32
Diet items
Dwarf least cisco (Coregonus sardinella) were the primary diet item found in stomachs of lake trout (Salvelinus namaycush) from Nutuvukti Lake. These fish, measured at about 90 mm (3.5 in) in length, were reproductively mature.
Dwarf least cisco (Coregonus sardinella) were the primary diet item found in stomachs of lake trout (Salvelinus namaycush) from Nutuvukti Lake. These fish, measured at about 90 mm (3.5 in) in length, were reproductively mature.
Jigging for lake trout
Biologists jig for lake trout (Salvelinus namaycush) on Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Thick smoke from wildfires in the Kobuk River and Koyukuk River valleys settled over the lake for a week during field sampling in August.
Biologists jig for lake trout (Salvelinus namaycush) on Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Thick smoke from wildfires in the Kobuk River and Koyukuk River valleys settled over the lake for a week during field sampling in August.
Aquatic plants
Emergent vegetation growing in the shallow water of Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Emergent vegetation provides habitat for aquatic insects and small fishes.
Emergent vegetation growing in the shallow water of Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Emergent vegetation provides habitat for aquatic insects and small fishes.
Lake trout from Chandler Lake
A field biologist landed this large 7 kg (15 lb) lake trout (Salvelinus namaycush) on the shore of Chandler Lake, Gates of the Arctic National Park. The lake trout was collected as part of a study investigating the biomagnification of mercury through lake food webs.
A field biologist landed this large 7 kg (15 lb) lake trout (Salvelinus namaycush) on the shore of Chandler Lake, Gates of the Arctic National Park. The lake trout was collected as part of a study investigating the biomagnification of mercury through lake food webs.
Algae collection
Algae collected from rocks in the littoral zone of Chandler Lake, Gates of the Arctic National Park. Algae samples are used to establish an energy baseline for the food web, as primary producers – organisms that produce their own food through photosynthesis – algae provide food to the lake’s benthic macroinvertebrates.
Algae collected from rocks in the littoral zone of Chandler Lake, Gates of the Arctic National Park. Algae samples are used to establish an energy baseline for the food web, as primary producers – organisms that produce their own food through photosynthesis – algae provide food to the lake’s benthic macroinvertebrates.
Chandler Lake fishing
The sampling team at Chandler Lake, Gates of the Arctic National Park, walk along the shoreline to a new angling location. While treated to beautiful views, field biologists fished for lake trout (Salvelinus namaycush) as part of a study investigating the biomagnification of mercury through lake food webs.
The sampling team at Chandler Lake, Gates of the Arctic National Park, walk along the shoreline to a new angling location. While treated to beautiful views, field biologists fished for lake trout (Salvelinus namaycush) as part of a study investigating the biomagnification of mercury through lake food webs.
Chelle Lake trout collection
A biologist samples lake trout (Salvelinus namaycush) tissues. This fish, captured in Chelle Lake within Wrangell-St. Elias National Park, is part of a study investigating the biomagnification of mercury through lake food webs. Mount Drum rises above the hills to the southeast.
A biologist samples lake trout (Salvelinus namaycush) tissues. This fish, captured in Chelle Lake within Wrangell-St. Elias National Park, is part of a study investigating the biomagnification of mercury through lake food webs. Mount Drum rises above the hills to the southeast.
Lake in Wrangell St. Elias National Park
Lake in Wrangell St. Elias National Park. This is part of a study examining mercury in lake food webs.
Lake in Wrangell St. Elias National Park. This is part of a study examining mercury in lake food webs.
Round whitefish in Wrangell St. Elias National Park
Round whitefish in Wrangell St. Elias National Park. Round whitefish (Prosopium cylindraceum) were collected as part of a study examining mercury in lake food webs.
Round whitefish in Wrangell St. Elias National Park. Round whitefish (Prosopium cylindraceum) were collected as part of a study examining mercury in lake food webs.
Longnose sucker in Wrangell St. Elias National Park
Longnose sucker in Wrangell St. Elias National Park. Longnose suckers (Catostomus catostomus) were collected as part of a study examining mercury in lake food webs.
Longnose sucker in Wrangell St. Elias National Park. Longnose suckers (Catostomus catostomus) were collected as part of a study examining mercury in lake food webs.
Fishing for lake trout in Wrangell St. Elias National Park
Fishing for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) and Ashley Stanek (USGS – ASC) angle for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs.
Fishing for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) and Ashley Stanek (USGS – ASC) angle for lake trout (Salvelinus namaycush) in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs.
Burbot in Wrangell St. Elias National Park
Burbot in Wrangell St. Elias National Park. Burbot (Lota lota) were collected as part of a study examining mercury in lake food webs.
Burbot in Wrangell St. Elias National Park. Burbot (Lota lota) were collected as part of a study examining mercury in lake food webs.
Fyke net in Wrangell St. Elias National Park
Fyke net in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) adjusts a fyke net installed in a lake in Wrangell St. Elias National Park. Fyke nets are used to non-lethally capture fish.
Fyke net in Wrangell St. Elias National Park. Sam Graf (NPS – LACL) adjusts a fyke net installed in a lake in Wrangell St. Elias National Park. Fyke nets are used to non-lethally capture fish.
Arctic grayling in Wrangell St. Elias National Park
Arctic grayling (Thymallus arcticus) in Wrangell St. Elias National Park. Arctic grayling were collected as part of a study examining mercury in lake food webs.
Arctic grayling (Thymallus arcticus) in Wrangell St. Elias National Park. Arctic grayling were collected as part of a study examining mercury in lake food webs.
Lake trout sampling
Lake trout with stomach contents in Wrangell St. Elias National Park. Dorsal muscle collection and stomach content analysis are used to evaluate biomagnification of mercury in Lake trout (Salvelinus namaycush). Stomach contents visible below the fish consist primarily of slimy sculpin (Cottus cognatus).
Lake trout with stomach contents in Wrangell St. Elias National Park. Dorsal muscle collection and stomach content analysis are used to evaluate biomagnification of mercury in Lake trout (Salvelinus namaycush). Stomach contents visible below the fish consist primarily of slimy sculpin (Cottus cognatus).
Collecting benthic macroinvertebrates
Collecting benthic macroinvertebrates in Wrangell St. Elias National Park. Sarah Laske (USGS – ASC) collects benthic macroinvertebrates using a kick net in a lake in Wrangell St. Elias National Park, Alaska, as part of a study examining mercury in lake food webs.
Collecting benthic macroinvertebrates in Wrangell St. Elias National Park. Sarah Laske (USGS – ASC) collects benthic macroinvertebrates using a kick net in a lake in Wrangell St. Elias National Park, Alaska, as part of a study examining mercury in lake food webs.
Collecting zooplankton in Wrangell St. Elias National Park
Sarah Laske (USGS - ASC) collects zooplankton from a lake using a plankton net in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs. Sam Graf (NPS - LACL) angles.
Sarah Laske (USGS - ASC) collects zooplankton from a lake using a plankton net in Wrangell St. Elias National Park as part of a study examining mercury in lake food webs. Sam Graf (NPS - LACL) angles.
Lake trout otolith section
Cross section of a lake trout (Salvelinus namaycush) otolith collected from a fish in Lake Clark National Park. Otoliths, also known as 'earstones' are hard, calcium carbonate structures located directly behind the brain of bony fishes.
Cross section of a lake trout (Salvelinus namaycush) otolith collected from a fish in Lake Clark National Park. Otoliths, also known as 'earstones' are hard, calcium carbonate structures located directly behind the brain of bony fishes.
Filtering phytoplankton from lake water
Phytoplankton is filtered from lake water for analysis of mercury content. Photo courtesy of U.S. National Park Service, Public Domain.
Phytoplankton is filtered from lake water for analysis of mercury content. Photo courtesy of U.S. National Park Service, Public Domain.
Water collection, Alaska
Biologist collects water from a lake in Lake Clark National Park. Photo courtesy of U.S. National Park Service, Public Domain.
Biologist collects water from a lake in Lake Clark National Park. Photo courtesy of U.S. National Park Service, Public Domain.
Juvenile sockeye salmon, Alaska
Juvenile sockeye salmon (Oncorhynchus nerka) captured in Lake Clark National Park as part of a study examining mercury in lake food webs.
Juvenile sockeye salmon (Oncorhynchus nerka) captured in Lake Clark National Park as part of a study examining mercury in lake food webs.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government