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.

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To address this issue we have applied dendrochronology (tree-ring analysis) techniques to growth-increment widths in otoliths from lake trout (Salvelinus namaycush). We have developed a growth record for lake trout from the Chandler Lake system in Gates of the Arctic National Park and Preserve and are currently working on a similar effort in Lake Clark National Park. Sockeye salmon are a keystone species within Lake Clark National Park and Preserve, which was established “..to protect the watershed necessary for the perpetuation of the red [sockeye] salmon fishery in Bristol Bay.” Numerous lakes in Lake Clark National Park are important salmon nurseries that are sensitive to climate change, and increasing temperatures may lead to profound changes in productivity by altering the timing of ice break-up, the timing and duration of thermal stratification, and the timing and intensity of nutrient upwelling. Given that these high-latitude landscapes are among the most likely to experience rapid climate change in the coming decades, the relationships between lake biology and climate variability must be better quantified to forecast impacts on the productivity of sockeye salmon and resident fishes. To address the implications of climate variability in lakes for fish, we borrow from the tree-ring sciences to develop multidecadal chronologies from lake trout otoliths. Just as tree-ring data capture histories of climate and productivity in terrestrial systems, we propose that lake trout otolith data will provide analogous information for lake ecosystems. A particular strength of this study is that final trout chronologies will be exactly dated, allowing us to make high quality comparisons with direct observations of climate (instrumental records) and biology (salmon escapement). Thus, we are developing lake trout otolith chronologies in lake ecosystems of Lake Clark National Park and Preserve to i) quantify long-term effects of climate on growth, ii) evaluate the influence of marine-derived nutrient input from sockeye salmon returns, and iii) compare long-term rates of change in freshwater and terrestrial ecosystems using lake trout and tree-ring chronologies.

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
Winter Habitat of Juvenile Dolly Varden in the Canning River
Arctic Lake Food Webs
Ecosystem Shifts in Arctic Seas
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
Below are multimedia items associated with this project.
Below are publications associated with this project.
Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems
- Overview
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.
Sources/Usage: Public Domain. Visit Media to see details.A transverse cross-section of a sagittal otolith from a lake trout collected in April, 1989, from Chandler Lake, Alaska, USA. Decadal growth increments (1980, 1970, and 1960) are dotted.(Credit: Bryan A. Black, University of Texas. Public domain.) Return to Wildlife, Fish, and Habitats >> Fish and Aquatic Ecology
To address this issue we have applied dendrochronology (tree-ring analysis) techniques to growth-increment widths in otoliths from lake trout (Salvelinus namaycush). We have developed a growth record for lake trout from the Chandler Lake system in Gates of the Arctic National Park and Preserve and are currently working on a similar effort in Lake Clark National Park. Sockeye salmon are a keystone species within Lake Clark National Park and Preserve, which was established “..to protect the watershed necessary for the perpetuation of the red [sockeye] salmon fishery in Bristol Bay.” Numerous lakes in Lake Clark National Park are important salmon nurseries that are sensitive to climate change, and increasing temperatures may lead to profound changes in productivity by altering the timing of ice break-up, the timing and duration of thermal stratification, and the timing and intensity of nutrient upwelling. Given that these high-latitude landscapes are among the most likely to experience rapid climate change in the coming decades, the relationships between lake biology and climate variability must be better quantified to forecast impacts on the productivity of sockeye salmon and resident fishes. To address the implications of climate variability in lakes for fish, we borrow from the tree-ring sciences to develop multidecadal chronologies from lake trout otoliths. Just as tree-ring data capture histories of climate and productivity in terrestrial systems, we propose that lake trout otolith data will provide analogous information for lake ecosystems. A particular strength of this study is that final trout chronologies will be exactly dated, allowing us to make high quality comparisons with direct observations of climate (instrumental records) and biology (salmon escapement). Thus, we are developing lake trout otolith chronologies in lake ecosystems of Lake Clark National Park and Preserve to i) quantify long-term effects of climate on growth, ii) evaluate the influence of marine-derived nutrient input from sockeye salmon returns, and iii) compare long-term rates of change in freshwater and terrestrial ecosystems using lake trout and tree-ring chronologies.
Sources/Usage: Some content may have restrictions. Visit Media to see details.Spearman correlations between the lake trout master chronology and monthly mean air temperature and degree days from Bettles, AK. Degree days were calculated only for the months of April through October. Asterisk denotes significance at the p \ 0.01 level. Inset The relationship between the lake trout master chronology and mean August air temperature at Bettles, AK. r 2 = 0.32 (p = 0.005). There was no significant autocorrelation in the residuals; DW = 2.39 (p = 0.19). b Lake trout master chronology and August air temperature. Both time series are normalized to a mean of 0 and standard deviation of 1.(Credit: Bryan A. Black, University of Texas. Graphic used in publication) - 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).Winter Habitat of Juvenile Dolly Varden in the Canning River
In the Arctic, rivers often freeze all the way to the bottom each winter leaving fish with limited habitat where they can survive.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.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
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater 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. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake syAuthorsB.A. Black, Vanessa R. von Biela, Christian E. Zimmerman, Randy J. Brown