Michael A. Litzow

Michael A. Litzow
University of Alaska Fairbanks · College of Fisheries and Ocean Sciences

PhD

About

59
Publications
7,993
Reads
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1,962
Citations
Citations since 2017
35 Research Items
940 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Additional affiliations
August 2009 - present
Farallon Institute for Advanced Ecosystem Research
Farallon Institute for Advanced Ecosystem Research
Position
  • Ecologist
August 2003 - August 2007
National Marine Fisheries Service
Position
  • Research Fisheries Biologist

Publications

Publications (59)
Article
Full-text available
The temperature-size rule predicts that climate warming will lead to faster growth rates for juvenile fishes but lower adult body size. Testing this prediction is central to understanding the effects of climate change on population dynamics. We use fisheries-independent data (1999-2019) to test predictions of age-specific climate effects on body si...
Article
Full-text available
Climate change makes fish stocks more vulnerable to recruitment failure, and early detection of these events is important for an effective management response. Here, we evaluate the value of larval and juvenile surveys, and a thermal spawning habitat index, for predicting recruitment in two economically important gadids, walleye pollock (Gadus chal...
Article
Full-text available
Ocean ecosystems are vulnerable to climate-driven perturbations, which are increasing in frequency and can have profound effects on marine social-ecological systems. Thus, there is an urgency to develop tools that can detect the response of ecosystem components to these perturbations as early as possible. We used Bayesian Dynamic Factor Analysis (D...
Article
Full-text available
Pacific salmon (Oncorhynchus spp.) are exposed to increased environmental change and multiple human stressors. To anticipate future impacts of global change and to improve sustainable resource management, it is critical to understand how wild salmon populations respond to stressors associated with human-caused changes such as climate warming and oc...
Article
Full-text available
Sustainability—maintaining catches within the historical range of socially and ecologically acceptable values—is key to fisheries success. Climate change may rapidly threaten sustainability, and recognizing these instances is important for effective climate adaptation. Here, we present one approach for evaluating changing sustainability under a cha...
Article
The Pacific cod (Gadus macrocephalus) fishery recently collapsed in the Gulf of Alaska after a series of marine heatwaves that began in 2014. To gauge the likelihood of population recovery following these extreme warming events, we investigate potential thermal stress on age-0 cohorts through a comprehensive analysis of juvenile cod abundance, cond...
Article
Full-text available
Plain Language Summary Novel climates, or combinations of climate conditions that have not been previously observed in a particular place, can cause surprising outcomes for ecosystem services like fisheries production. We found that during an extreme Gulf of Alaska warming event in 2014–2019, correlations changed between the Pacific Decadal Oscilla...
Article
The Gulf of Alaska experienced extreme temperatures during 2014-2019, including the four warmest years ever observed. The goal of this study is to evaluate the ecological consequences of that warming event, across multiple trophic levels and taxa. We tested for evidence that observed sea surface temperature (SST) anomalies were outside the envelope...
Article
Full-text available
The Gulf of Alaska experienced extreme temperatures during 2014-2019, including the four warmest years ever observed. The goal of this study is to evaluate the ecological consequences of that warming event, across multiple trophic levels and taxa. We tested for evidence that observed sea surface temperature (SST) anomalies were outside the envelope...
Article
Ecologists and oceanographers inform population and ecosystem management by identifying the physical drivers of ecological dynamics. However, different research communities use different analytical tools where, for example, physical oceanographers often apply rank‐reduction techniques (a.k.a. empirical orthogonal functions [EOF]) to identify indica...
Article
Climate change is likely to change the relationships between commonly used climate indices and underlying patterns of climate variability, but this complexity is rarely considered in studies using climate indices. Here, we show that the physical and ecological conditions mapping onto the Pacific Decadal Oscillation (PDO) index and North Pacific Gyr...
Article
Multivariate data reduction techniques are widely used to describe modes of variability in atmospheric and oceanographic conditions for the world’s oceans. Dominant modes of variability such as the Pacific Decadal Oscillation (PDO) are typically defined as a statistical summary of physical measurements, and include both principle components represe...
Article
We tested the hypothesis that ocean temperature effects on productivity for northeast Pacific pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum salmon (Oncorhynchus keta) changed after 1988–1989, coincident with a decline in Aleutian Low variance. Nonstationary temperature effects were tested with three different analytical meth...
Article
Full-text available
Common approaches for summarizing multivariate environmental or community data assume that relationships among variables are stationary over time, and this assumption is often not tested. Here we test the hypothesis that relationships among environmental and community time series are nonstationary in the Gulf of Alaska ecosystem (North Pacific Ocea...
Article
Full-text available
Studies of climate effects on ecology often account for non-stationarity in individual physical and biological variables, but rarely allow for non-stationary relationships among variables. Here, we show that non-stationary relationships among physical and biological variables are central to understanding climate effects on salmon (Onchorynchus spp....
Data
Detailed results for models that only include density dependence. Table of model selection values (AICc) comparing null models (constant productivity, or log(R/S) independent of spawners) to models that estimated density dependence via the Ricker stock-recruitment relationship. For each species, the best model and all models within 1 log-likelihood...
Data
Detailed results for models that only include effects of juvenile competition. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of juvenile competition. All models with juvenile competition included also include density dependence (the sockeye model...
Data
Detailed results for models that only include environmental covariates. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of environmental effects. All models that include environmental predictors also include density dependence (the sockeye models w...
Data
Detailed results for models that only include effects of predation and adult competition. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of predation or adult competition on wild salmon productivity. All models with predation or adult competition...
Data
Detailed results for models that only include effects of EVOS. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of the EVOS event (pulse, press, pulse/recovery with various lags). All models that include an EVOS impact also include density dependenc...
Article
Full-text available
The presence of early warning signals (EWS) for regime shifts was tested for in the Bering Sea demersal community during a 2006 to 2013 cold anomaly. During this cold period, community-wide recruitment and distribution patterns failed to reverse responses observed during the previous 2 to 4 decades of warming. These observations are consistent with...
Article
Full-text available
The Exxon Valdez oil spill occurred in March 1989 in Prince William Sound, Alaska, and was one of the worst environmental disasters on record in the United States. Despite long-term data collection over the nearly three decades since the spill, tremendous uncertainty remains as to how significantly the spill affected fishery resources. Pacific herr...
Data
Total estimated run size of wild chum in Prince William Sound. (TIFF)
Data
Detailed results for models that only include effects of EVOS. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of the EVOS event (pulse, press, pulse/recovery with various lags). All models that include an EVOS impact also include density dependenc...
Data
Detailed results for models that only include environmental covariates. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of environmental effects. All models that include environmental predictors also include density dependence (the sockeye models w...
Data
Detailed results for models that only include effects of juvenile competition. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of juvenile competition. All models with juvenile competition included also include density dependence (the sockeye model...
Data
Hatchery release trends for coho, sockeye, chum, and pink salmon, 1979–2014. (TIFF)
Data
Historic freshwater discharge into Prince William Sound, 1931–2010 (Royer 1982, IMS 2016). The dashed horizontal line represents the mean, and the dashed vertical lines represent the time period included in our analyses. (TIFF)
Data
Detailed results for models that only include effects of predation and adult competition. Table of model selection values (AICc) comparing models without covariates (i.e. models presented in S1 Table) to models that also estimate an impact of predation or adult competition on wild salmon productivity. All models with predation or adult competition...
Data
Residuals from a simple Ricker stock-recruit model fit separately to each population. Sockeye time series versus year and total pink salmon hatchery returns (neither covariate included in this model). Using the model selection described in main text and a model that integrates all three time series in the same analysis, the model with the inclusion...
Data
Total harvest of Unakwik District sockeye salmon. (TIFF)
Data
Detailed results for models that only include density dependence. Table of model selection values (AICc) comparing null models (constant productivity, or log(R/S) independent of spawners) to models that estimated density dependence via the Ricker stock-recruitment relationship. For each species, the best model and all models within 1 log-likelihood...
Article
Full-text available
Early warning signals (EWS) might dramatically improve our ability to manage nonlinear ecological change. However, the degree to which theoretical EWS predictions are supported in empirical systems remains unclear. The goal of this study is to make recommendations for identifying the types of ecological transitions that are expected to show EWS. We...
Article
Statistical indicators such as rising variance and rising skewness in key system parameters may provide early warning of "regime shifts" in communities and populations. However, the utility of these indicators has rarely been tested in the large, complex ecosystems that are of most interest to managers. Crustacean fisheries in the Gulf of Alaska an...
Article
Full-text available
In areas of the North Pacific that are largely free of overfishing, climate regime shifts - abrupt changes in modes of low-frequency climate variability - are seen as the dominant drivers of decadal-scale ecological variability. We assessed the ability of leading modes of climate variability (PDO, NPGO, AO, PNA, NPI, ENSO) to explain decadal-scale...
Conference Paper
Marine ecosystems may respond to external forcing with abrupt reorganizations that are economically and socially devastating to fishing communities. There is currently no method allowing early warning of these reorganization events. However, recent developments in ecosystem modeling suggest a novel approach to this problem: using the variance of ke...
Article
Full-text available
We used a 112-year time series of Alaskan fishery catches to test competing hypotheses concerning trends in mean catch trophic level, a widely used indicator of fisheries sustainability. We found that mean trophic level has generally remained steady or increased in recent decades on Alaska-wide and regional scales, indicating stable catches of high...
Article
Full-text available
Phase transitions between alternate stable states in marine ecosystems lead to disruptive changes in ecosystem services, especially fisheries productivity. We used trawl survey data spanning phase transitions in the North Pacific (Gulf of Alaska) and the North Atlantic (Scotian Shelf) to test for increases in ecosystem variability that might provid...
Article
Full-text available
Seasonal ice cover creates a pool of cold bottom water on the eastern Bering Sea continental shelf each winter. The southern edge of this cold pool, which defines the ecotone between arctic and subarctic communities, has retreated approximately 230 km northward since the early 1980s. Bottom trawl surveys of fish and invertebrates in the southeaster...
Article
Pacific capelin (Mallotus villosus) populations declined dramatically in the Northeastern Pacific following ocean warming after the regime shift of 1977, but little is known about the cause of the decline or the functional relationships between capelin and their environment. We assessed the distribution and abundance of spawning, non-spawning adult...
Article
Understanding how climate regulates trophic control may help to elucidate the causes of transitions between alternate ecosystem states following climate regime shifts. We used a 34-year time series of the abundance of Pacific cod (Gadus macrocephalus) and five prey species to show that the nature of trophic control in a North Pacific ecosystem depe...
Article
Climate regime shifts have recently occurred in the North Pacific (1998-1999) and the Arctic (2000), but the nature of biological reaction to these events is poorly understood. An index of local climate (1960-2005), and data from commercial fishery catches (1960-2004) and from small-mesh trawl surveys (1972-2005) are used to assess the impacts of t...
Article
Full-text available
Climate regime shifts force fish communities through rapid transitions between alternate species assemblages, but little is known about the role that biochemical ecology plays in these transitions. We document a biochemical effect of climate-induced community transitions in boreal oceans: opposite population trajectories of lipid-rich and lipid-poo...
Article
Summary 1. The quality-variability trade-off hypothesis predicts that (i) energy density (kJ g − 1 ) and spatial-temporal variability in abundance are positively correlated in nearshore marine fishes; and (ii) prey selection by a nearshore piscivore, the pigeon guillemot ( Cepphus columba Pallas), is negatively affected by variability in abundance....
Article
Full-text available
Low spatiotemporal variability in the abundance of nonschooling prey might allow Pigeon Guillemots (Cepphus columba) to maintain the high chick provisioning rates that are characteristic of the species. We tested predictions of this hypothesis with data collected with beach seines and scuba and hydroacoustic surveys in Kachemak Bay, Alaska, during...
Article
Full-text available
Low spatiotemporal variability in the abundance of nonschooling prey might allow Pigeon Guillemots (Cepphus columba) to maintain the high chick provisioning rates that are characteristic of the species. We tested predictions of this hypothesis with data collected with beach seines and scuba and hydroacoustic surveys in Kachemak Bay, Alaska, during...
Article
Full-text available
We use data on pigeon guillemots Cepphus columba to test the hypothesis that discretionary time in breeding seabirds is correlated with variance in prey abundance. We measured the amount of time that guillemots spent at the colony before delivering fish to chicks (“resting time”) in relation to fish abundance as measured by beach seines and bottom...
Article
Full-text available
Populations of the pigeon guillemot (Cepphus columba) and other piscivores have been in decline for several decades in the Gulf of Alaska and Bering Sea, and a decline in abundance of lipid-rich schooling fishes is hypothesized as the major cause. We tested this hypothesis by studying the breeding biology of pigeon guillemots during 1995-1999 while...
Article
We evaluated pigeon guillemots (Cepphus columba) as monitors of nearshore fish abundance and community composition during 1995–1999 at Kachemak Bay, Alaska. We studied the composition of chick diets at 10 colonies and simultaneously measured fish abundance around colonies with beach seines and bottom trawls. Sandeels (Ammodytes hexapterus) formed t...
Article
In 1997, we compared the haematological and plasma biochemical profiles among populations of pigeon guillemots, Cepphus columba, in areas oiled and not oiled by the 1989 Exxon Valdez oil spill (EVOS) that occurred in Prince William Sound (PWS), Alaska. Pigeon guillemot populations in PWS were injured by EVOS and have not returned to pre-spill level...
Article
Full-text available
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Article
The Eastern Bering Sea is characterized by its broad (> 500km), shallow (mean depth = 70m), and seasonally ice-covered shelf. The spatial extent of ice and the timing of ice retreat are driven by large-scale atmospheric forcing and vary considerably interannually. This variability affects the spatial distribution of fish and invertebrates, the timi...

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