Research Projects

Environmental change causes physiological impacts that can last years in long-lived species, yet there is a dearth of methods for quantifying such impacts and their population effects across the necessary decadal timescales. This data gap is particularly acute for long-lived marine species, despite the fact that many
marine regions are undergoing rapid environmental change, with largely unknown physiological effects. We propose to use a recently developed technique, baleen hormone analysis, to investigate multi-year physiological impacts of shifts in the marine environment on stress, growth and reproduction in bowhead
whales (Balaena mysticetus). Bowheads’ exceptionally long lifespan of >200 years, combined with well-documented environmental shifts in their North Pacific winter and Arctic Ocean summer habitats, make them an ideal platform to study and model the multi-year responses of organismal physiology, and consequent population effects, after episodes of rapid environmental change. Bowhead baleen, a 1-3 m long keratinized feeding apparatus, contains hormones that comprise a continuous longitudinal endocrine record spanning the duration of baleen growth (10-20 years), with sufficient temporal resolution to separate summer vs. winter habitat use. Baleen hormone profiles combined with stable isotope analyses enable accurate reconstruction of detailed, decade-scale physiological histories of individual whales. We propose to analyze archived museum baleen specimens (spanning more than 150 years) to test fundamental questions regarding relationships of lifespan, body size, growth, and vulnerability to environmental change. Specifically, the proposed research tests the hypothesis that sudden changes in marine conditions cause multi-year impacts in stress, growth and reproduction in a long-lived mammal, and that this information can be used to forecast population-level responses to ongoing environmental change. Project objectives include: (1) Determine lifetime endocrine history of juvenile bowheads sampled before and after a 1977 ecological regime shift, using a panel of four hormones to assess stress physiology; (2) Assess potential impacts of ecological change and stress on juvenile growth rate; (3) Expand our long-term dataset on historic patterns of stress and reproduction via study of adult baleen
specimens; (4) Use the multi-year individual physiological histories provided by baleen to model linkages between ecological change, individual physiology, and potential population impacts.

Our previous community-based participatory research at Northeast Cape (NEC) on St. Lawrence Island (SLI) found elevated levels of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and mercury (Hg) in sediments and biota within the watershed at the formerly used defense (FUD) sites. We found elevated OCPs and PCBs in serum of the SLI people due to both long-range transport and military-derived sources, with the highest levels of PCBs in people who have traditional and familial connections with use NEC, including for subsistence. Concentrations of persistent organic pollutants (POPs) in our resident fish model, the stickleback, closely mirror concentrations in the blood serum of SLI residents, indicating their efficacy as sentinel species on SLI. Despite extensive remediation at NEC, short-lived lower trophic level fish in the Suqitughneq (Suqi) River remain contaminated with PCBs, OCPs, and Hg originating from the FUD site, at levels that exceed EPA fish consumption guidelines for cancer risk. Elevated contaminant levels and disrupted health in Suqi River fish indicate potential health threats for residents and that site remediation is incomplete. Our overarching goal is to advance scientific understanding of the exposure pathways and long-term human health consequences associated with contaminant exposure from FUD sites and inform interventions necessary to protect the health and long-term well-being of the people of SLI as they re-establish their traditional community at NEC. We propose to build on our prior discoveries and continue our collaboration with the communities of SLI to investigate potential exposure pathways and biological impacts of persistent contamination associated with the FUD sites at NEC on SLI (Aim 1). We will analyze PCBs, OCPs, and Hg in the water of the Suqi and Tapisaggak rivers, as well as in traditional foods and air samples to assess ingestion and inhalation as potential exposure pathways. We will build on work with stickleback as a sentinel species to determine biological effects of contaminants on endocrine function and organ-specific histopathology. In Aim 2, we will characterize and quantify body burden of contaminants, and linkages to health outcomes, in people associated with NEC. In Aim 3, we will inform decisions and interventions to protect the health of the people of SLI and enable re-establishment of the traditional community at NEC. We will provide information that will lead to improved remediation, provide data and traditional knowledge to inform the public health consultations and assessments, and develop a community-based public health action plan and interventions to protect health, ensure equity in decision-making, and restore the NEC community. This study will have local and circumpolar arctic implications for Indigenous communities. Locally, we will provide data and implement actions necessary for re-establishing the community at NEC. Given that thousands of such Cold War military sites exist throughout the Arctic, often in close proximity to Indigenous communities, our project may serve as a model for environmental and health monitoring and policy action by other Arctic Indigenous Peoples.

The National Ecological Observatory Network (NEON) and its associated infrastructure should result in novel insights into fundamental questions in ecology. For example, ecologists recently used plant phenology data, some of which were collected by NEON, to show that the impact of urbanization on plant phenology depended upon variation in temperature and not just urbanization intensity (Li et al., 2019). However, the potential of NEON and its associated infrastructure have not been fully realized by organismal biologists. NEON has a clear focus on the responses of populations, communities, or ecosystems to environmental change, yet, NEON may also be well-suited for answering some of the major contemporary questions in organismal biology. These include topics that are closely related to the core mission of NEON such as 1) within-population responses to environmental change, 2) mechanisms facilitating ecological range expansions, and 3) macro-scale variation in behavior and physiology that capitalizes on the spatial-temporal replication that is possible through NEON. Through NEON, there is great potential for organismal biologists to answer key questions in their discipline and discover new patterns at spatiotemporal scales that have not previously been possible. NEON presents a “home” for new interdisciplinary research opportunities between ecologists and organismal biologists. The aim of this Research Coordination Network (RCN) is to integrate organismal biologists within the NEON community to answer outstanding and timely questions in organismal biology using the established NEON platform. Through inclusion of both established and early career researchers, this RCN should help to stimulate new research directions at NEON sites.

Baleen whales endure a myriad of intrinsic and extrinsic stressors, which make understanding the effects of individual anthropogenic disturbances difficult to identify and evaluate. Furthermore, scaling up the impacts of stress events from individuals to population-level consequences is challenging without representative samples from multiple demographic units and temporal periods. To date, most studies have been limited by sample size, demographic knowledge of individuals, and the ability to monitor multiple potential stressors simultaneously. Our research will fill these critical knowledge gaps through replicate physiological sampling of an accessible baleen whale population with synoptic measurement of multiple types of stressors. We propose to use the well-studied Pacific Coast Feeding Group (PCFG) sub-population of Eastern North Pacific gray whales (Eschrichtius robustus) as a case study to quantify and model baleen whale physiological response to different stressors.

Ancient people coped with stressful environmental and social challenges without recourse to modern medicine or technology. These challenges are similar to modern-day concerns, such as climate change, unequal distribution of resources, and political revolutions. Biochemical analyses of ancient human skeletal remains are an innovative way to understand individual responses in the past. Modern studies of cortisol, a stress hormone, show an increase in body tissues during times of stress, and epigenetic changes to the DNA that regulate gene expression are associated with early life stresses like famine, warfare, and abuse. We will test an innovative method of assessing stress with cortisol and epigenetic analyses on human bones for proof of concept. Pilot studies of these analyses on whales are promising but new in human remains. Individuals to be tested are from the Nasca culture of Southern Peru (AD 1-750) who experienced a drought, social conflict, and imperial invasion. Data gathered from this project will be compared with existing dietary and health data to create multifactorial biohistories of the Nasca people. Additionally, this project may lead to the addition of a novel and innovative test for human bone, among the most common material from archaeological sites.

The purpose of this proposed research is to investigate health disparities associated with fungicide exposure among migrant farmworkers and other residents in the Yuma region of Arizona. We will conduct analyses of human and rodent hair samples to examine associations between concentrations of metals/metalloids used in fungicides and adverse health outcomes. The data generated will form the basis of a proposal to NIH to investigate genotypic variants and variation in gene copy number that may play a role in vulnerability to diseases associated with exposure to these contaminants. Our ultimate goal is to develop precision medicine screening and interventions to reduce the impact of environmental contaminants in high exposure populations such as Yuma.

The objectives of this community-based participatory research (CBPR) project are to investigate exposures, endocrine effects, and mechanisms of developmental disruption associated with legacy contaminants and emerging flame retardant chemicals in two Yupik communities on St. Lawrence Island (SLI) in arctic Alaska. The Arctic is subject to atmospheric deposition of globally-distilled persistent organic pollutants (POPs), acting as a hemispheric sink for POPs that are transported from lower latitudes. Thus, the Arctic is significant as an indicator region and contains some of the most highly contaminated animals and people in the world. This study addresses a primary public health concern of the people of SLI by focusing on the levels and effects of legacy and emerging contaminants on the development of children in an arctic indigenous population that is vulnerable, underserved, and experiences significant health disparities. Other studies have shown that young children are more highly exposed than adults. Using innovative and minimally invasive techniques, we will assess exposures of children to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and emerging halogenated and non-halogenated organophosphate flame retardants. We will quantify PCBs and flame retardant chemicals in household dust, known to be an important exposure route. We will assess relationships among contaminant levels and evidence of health disruption via transcriptomics and endocrinology. We will use chemical concentrations in household dust and utilization of a subsistence diet as determined by stable isotope analysis to assess exposure pathways of these compounds. In order to understand the mechanistic basis of developmental disruption, and to have a reference for interpretation of human data, we will monitor patterns of gene expression, endocrinology, and histology of our resident fish model, the stickleback, from both contaminated and reference sites. Collectively, we will increase our understanding of routes of exposure, endocrine disruption, and effects on the transcriptome of Yupik children exposed to high levels of PCBs and flame retardant chemicals. This study provides an opportunity to investigate the levels of PBDEs and emerging flame retardants in nails and blood in relation to health outcomes of arctic indigenous children for the first time. Our CBPR project will also empower SLI communities with the knowledge and tools they need to address important health disparities in their communities. Our results will inform public health interventions and improve health outcomes of arctic children broadly. Furthermore, discovery of bioindicators relevant to early detection of developmental disruption will enable early intervention and improve health outcomes. Importantly, we will build capacity through our CBPR approach, public health interventions, and policy outreach, which will mitigate future exposure of SLI children to toxic chemicals.

There is growing interest in forecasting the impact of climate change on phenology in animals. Our ability to predict how species might alter their annual timing in response to rapid environmental change is constrained, however, by insufficient knowledge regarding the endogenous mechanisms animals use to keep time, the cues used to adjust timing, and the extent to which programmed seasonal cycles are physiologically plastic. The proposed study will investigate endogenous circannual induction and non-photoperiodic modulation of the neuroendocrine signals that trigger the termination of torpor and onset of reproduction in hibernating ground squirrels. While photoperiod likely acts to entrain the phase of circannual rhythms in ground squirrels, changes in day-length are not required for the persistence of life-long, internally-generated, circannual cycles of reproduction, molt, fattening, and hibernation. Specifically, ground squirrels spontaneously end torpor and undergo gonadal recrudescence in constant darkness without the stimulus of a changing photoperiod. In hibernating mammals, a precise integration must occur between the CNS signaling cascades controlling thermoregulation through the termination of torpor and the subsequent activation of the reproductive axis, but the neuroendocrine modulators that regulate these changes and how they are integrated are unknown. In seasonally breeding, photoperiodic vertebrates, the pars tuberalis (PT) of the pituitary plays an essential role in the timing of annual cycles, as it alters hypothalamic thyroid hormone (TH) availability by secreting thyroid stimulating hormone (TSH) in a light- or melatonin-sensitive manner, which acts on neighboring hypothalamic deiodinase expressing cells. The PT thyrotrophs themselves are now considered strong candidates for circannual timer cells, driving a thyroid-dependent seasonal physiology. This proposal tests the hypothesis that, in the absence of any photic cues, the termination of torpor and onset of reproduction are triggered by spontaneous changes in hypothalamic thyroid status driven by activation of thyrotroph cells in the PT. Additionally, we will test the hypothesis that plasticity in timing is driven by temperature-induced changes in hypothalamic deiodinase activity and/or through effects on downstream targets of the T3 signaling pathway, which occur independently of the PT. The proposed research has 4 objectives focused on delineating the neurobiological mechanisms involved in circannual activation and non-photic modulation of the reproductive axis in mammals: (1) to investigate the molecular mechanisms that underlie seasonal timing using immunohistochemistry and electron microscopy studies of the arctic ground squirrel PT and hypothalamus at different phases of the annual cycle, (2) to examine how reproductive timing can become disassociated from the circannual rhythm, (3) to determine how Ta influences the TH signaling pathway, and (4) to examine the physiological and behavioral effects of centrally administered TH during hibernation.

A grand challenge facing biology is understanding how genotypes generate specific phenotypes that influence population-level responses. Tackling this challenge is most urgent today because managing for impacts of climate change requires both understanding and predicting responses to a changing climate within and across levels of biological organization. This RCN will coalesce biologists and mathematical modelers working at different levels of biological organization who typically do not interact. The goal is to establish a new collaborative network spanning from genomes to populations to facilitate development of novel quantitative approaches to address the urgent challenge of predicting how vertebrate species and populations will respond to a changing climate. Primary activities include: (1) Creation of an initial core network of participants with expertise either at different levels of biological complexity and/or at creating and using mathematical models; (2) Expansion of the original network with special emphasis in recruiting young scientists; (3) Hosting annual workshops to foster education and formation of new interdisciplinary collaborations; (4) Training through exchanges between labs; and (5) Development and dissemination of webinars derived from the workshops.

Urea-nitrogen salvage occurs when urea, generated in the liver and passed to the bloodstream, diffuses into the gut where it is hydrolyzed by ureolytic microbes into NH3 and CO2. Microbially-liberated urea-N can then be utilized in biosynthesis by gut microbes as well as the host. Although long-understood to be important in ruminants, UNS in non-ruminants is not well described; however, it has recently been implicated in protein conservation in monogastric mammals, including humans, especially under conditions of dietary nitrogen deficiency or increased host nitrogen demand. While these studies suggest an important role for ureolytic microbes and UNS in human health, little is known about the degree to which UNS contributes to host biosynthetic processes, or about beneficial ureolytic microbes in the gut. Therefore, the goal of this study is to exploit the extreme phenotype of the arctic ground squirrel to discover interrelationships between host physiology and the gut microbial community important for host nitrogen metabolism. The hypotheses for this investigation are that 1) reliance upon UNS to meet nitrogen needs varies with dietary nitrogen content, host nitrogen demand and across the annual cycle of hibernation and activity, and that 2) the gut microbial community contains active ureolytic microbes that contribute significantly to host nitrogen homeostasis via UNS. The proposed experimental approach 1) utilizes injections of 13C/15N labeled urea to assess ureolytic activity and UNS in vivo via measurements of 13CO2 in breath (evidence of ureolysis in the gut) and 15N in tissues (evidence of use of microbially-liberated urea-N in host biosynthetic processes), 2) links phylogenic and functional diversity of the gut microbiota using next generation sequencing techniques (metagenomics and metatranscriptomics) and 3) specifically examines the abundance and activity of ureolytic bacteria in the gut using qPCR and qRT-PCR of microbial urease genes, respectively. Through comparison of relative changes in δ15N of tissues of hibernating arctic ground squirrels injected with labeled or unlabeled urea, studies in Specific Aim 1 will demonstrate the degree to which microbially-liberated urea-N is incorporated into host tissues under a long term fast. In Specific Aim 2, manipulation of dietary protein content will be used to determine the degree to which euthermic animals rely upon UNS for protein conservation under conditions of protein insufficiency. Similar diet manipulations in gestating and lactating squirrels will be conducted to evaluate the influence of dietary protein content and high nitrogen demand on the incorporation of microbially-liberated urea-N in mothers and pups in Specific Aim 3. Our experiments promise to yield an increased knowledge about interrelationships between the gut microbial community and host nitrogen homeostasis, ultimately contributing to our understanding of the relationship between the gut microbial community and human health, in particular under states of compromised nutrition (starvation, low dietary protein) and elevated N demand (gestation and lactation).

The Earth’s light-dark (LD) cycle is the strongest time-giver, or zeitgeber, for the entrainment of circadian rhythms and is thought to be the primary driver for the emergence and evolution of endogenous clocks. In polar regions, however, photoperiod exhibits extreme annual variation culminating with the sun remaining above and below the horizon for extended periods. The proposed study will investigate the persistence, entrainment, and function of circadian rhythms in a small, semi-fossorial arctic resident, the arctic ground squirrel (AGS; Urocitellus parryii), during the continuous daylight present during the active season and during continuous dark of the 6-8months of hibernation spent sequestered in a burrow. This research has four objectives that span from molecular and neurobiological mechanisms to physiological, behavioral and ecological adaptation: (1) determine when circadian rhythms of body temperature (Tb) and activity are exhibited during the annual cycle of free-living AGS and establish whether the onset of rhythmicity in spring coincides with first exposure to light, (2) determine whether circadian rhythms persist in the master clock of AGS during hibernation by measuring patterns of clock gene expression in the suprachiasmatic nuclei (SCN), (3) determine whether AGS are capable of entraining circadian rhythms to daily parametric changes in the spectral quality and/or intensity of light, and (4) investigate patterns of re-entrainment and the adaptive significance (i.e., function) of being diurnal in the arctic summer environment by experimentally phase-shifting free-living ground squirrels and measuring metabolic costs of nocturnal activity

The recent dramatic increase and geographic differences in frequency of reproductive diseases are likely to be due to changes in environment, including perchlorate exposure. Perchlorate (ClO4-) is a persistent, chlorinated water-soluble contaminant that is pervasive in the United States. As a toxicant, perchlorate poses a major risk to human health through ingestion of contaminated water, food, and milk from humans and animals. Perchlorate is a known endocrine disruptor that competitively inhibits iodide uptake through the Sodium-Iodide Symporter (NIS) in the thyroid, thus hindering thyroid hormone synthesis. Studies demonstrate, however, that perchlorate exposure masculinizes both female and male stickleback fish (Gasterosteus aculeatus), leading to hermaphroditic females and males with testicular hypertrophy, results that are not predicted by a simple, direct thyroid-disruption mechanism. The goal of this project is to reconcile the dominant paradigm of perchlorate action – exclusively by disruption of NIS in the thyroid – with masculinization of behavior, physiology, and morphology in stickleback and the contrasting finding of gonadal feminization in zebrafish (Danio rerio). The project’s goal is to identify previously unsuspected pathways by which perchlorate may impact human reproductive health. Our working hypothesis is that perchlorate disrupts gonadal development by acting independently of the thyroid. Aim 1 will determine whether all observed phenotypic responses to perchlorate exposure in stickleback and zebrafish are mediated by the thyroid by rescuing thyroid hormone levels in perchlorate—exposed fish. Aim 2 will define the functional roles of NIS and NIS-paralogs in disruption of gonadal development by perchlorate using in situ hybridization to localize mRNA, loss-of-function experiments to knock down expression of NIS and NIS-paralogs with morpholino anti-sense oligonucleotides and induced mutations, and gain-of-function experiments by over-expressing the NIS and NIS-paralogs. Aim 3 will determine the mechanism by which perchlorate alters sex differentiation using whole genome transcription profiling to determine which genes are early responders to perchlorate exposure, which are likely to be downstream genes, and whether responding genes are related to thyroid or gonadal development. Quantitative PCR (qPCR) and in situ hybridization will verify expression profiling results. Significance. The proposed experiments will identify molecular and physiological pathways by which perchlorate disrupts gonadal development, whether solely via NIS in the thyroid or by a different mechanism. Because perchlorate is a pervasive contaminant in the U.S., our proposed work has direct implications for human health, particularly regarding thyroid diseases and disorders of sexual development.

As the farthest north hibernating mammal in North America, the arctic ground squirrel (Spermophilus parryii) is exposed to profound seasonal changes in photoperiod and ambient temperature (Ta). S. parryii may exhibit the most extreme hibernation physiology known: capable of supercooling core body temperature (Tb) to -2.9°C, reducing metabolic rate (MR) to 2% of basal for weeks, and able to survive the arctic winter (ca. 250 days) solely on endogenous reserves. Perhaps uniquely among hibernators, S. parryii defend large thermal gradients (10-30°C) between Tb and Ta by substantially increasing MR while still at subzero Tb. We hypothesize that this requires a shift in metabolic fuel use that reduces lean mass; however, the endogenous source of fuels used, the mechanisms of fuel switching at low Tb, the lower Ta limits to hibernation, and the consequences of extreme hibernation conditions for body condition, overwinter survival, and reproductive fitness are not known. Objectives and methods: This research has four objectives that encompass genetic, molecular, organismal, and population-level approaches: (1) determine the source and extent of lean mass use during hibernation at varying Ta, using changes in 15N/14N to identify tissues catabolized for fuel, (2) quantify genomic changes involved in metabolic enzyme expression that regulate fuel use using quantitative real-time PCR, (3) identify the thermal limits to metabolic support of hibernation in S. parryii using respirometry and stable isotopes to track metabolic changes at progressively lower Ta, and (4) extrapolate these physiological traits to natural populations by tracking hibernacula and body temperatures, lean mass loss, isotope ratios, and components of fitness in ground squirrels in the field.

The population of blue king crab (BKC, Paralithodes platypus) in the Pribilof Islands, Alaska, has declined precipitously, and is now defined as overfished. We seek to understand the relationship between first-year survival of Pribilof Islands BKC, environmental change, and Essential Fish Habitat (EFH) for that species. We recently completed Phase 1 of this study with funding from the NPRB, “Development of cultivation techniques for blue king crab larvae,” during which we determined the best conditions for culturing crab larvae in the laboratory. This proposal is for Phase 2, covering two years of laboratory research, and building on what we have already learned. In Year 1 we will study embryonic development and the effects of temperature on it. This will be conducted by holding egg-bearing female crabs at different temperatures, and microscopic examination and measurement of embryos at periodic intervals. In Year 2, we will conduct research on the physiology of hatching relative to temperature and oxygen consumption, and determine if hatch timing is controlled by the embryos or the parent crab. We will also study the habitat selection by larval and juvenile BKC, and the effects of environment and habitat on survival of early juvenile crabs.

The proposed research will utilize Quantitative Fatty Acid Signature Analysis (QFASA) and stable isotope analysis to estimate the diets of tufted puffins (Fratercula cirrhata) breeding in Chiniak Bay, Kodiak, AK.  The primary objectives of this study are to assess seasonal and inter-annual variation in the diets of adult and nestling puffins and to investigate how this variation relates to reproductive success, chick growth rates, and forage fish availability.  This study, in collaboration with the University of Alaska’s Gulf Apex Predator-prey (GAP) program, will enable us to determine the effects of changing oceanographic and foraging conditions on the diets of tufted puffins and to evaluate their use as biological indicators of forage fish availability in the Gulf of Alaska.  The proposed research will also provide insight into the potential effects of changing foraging conditions on puffin populations that may result from climatic fluctuations, commercial exploitation of fisheries resources, and/or long-term global warming.

The influence of ocean regime shifts on the relative abundance of groundfish is well documented. Current observations suggest that the warm regime of the Bering Sea and Gulf of Alaska may be reverting to conditions characterized by the pre-1977 cold regime. This regime, characterized by colder surface water temperatures, favored recruitment of forage species and a reduced biomass of walleye pollock (Theragra chalcogramma).  While the majority of reports have examined these changes in species abundance in the context of life history characteristics, food availability and predation, there is a lack of information describing changes in the physiology of walleye pollock as a result of changes in environmental temperature.  Walleye pollock, as well as most other marine fishes, are heterothermic ectotherms and thus are subject to changes in metabolic rate as a function in environmental temperature.  Given the association of metabolic demands and environmental temperature, physiological tradeoffs must occur as walleye pollock attempt to adapt to and function in a changed environment.  These tradeoffs may manifest themselves in how forage is assimilated and partitioned into biologic needs such as growth and reproduction.  We propose to perform a series of tests, seasonally, that examine the swimming performance of walleye pollock subjected to different temperature regimes, assess alterations in metabolic demands associated with water temperature change, and link these observations to intra-annual variations in organosomatic indices and plasma constituents.  Through incorporation of these data into the current bioenergetic model for walleye pollock, both the reliability and precision of predicting stock strength, recruitment and energy required to maintain stocks of pollock will be increased.

The Gulf Apex Predator-prey research program (GAP) was initiated in 1999 by University of Alaska Fairbanks faculty in Kodiak to address trophic-level questions of immediate biological and economic concern in the western Gulf of Alaska. From 2001-2003, GAP received annual Congressional appropriations to address Steller sea lion-driven questions and hypotheses regarding the interactions of environment, prey, competitors, and predators in the Kodiak region. Results from research in FY01-03 (GAP I) laid the foundation for further investigations which are outlined in the proposal for GAP research in FY04-06 (GAP II). GAP’s interrelated studies have focused on Steller sea lion concerns and also broadly assessed the degree of temporal variability and dietary overlap among Kodiak’s sympatric apex predators. They are distinct but related hypothesis-driven research projects that explore the processes that drive populations of their prey within a dynamic marine environment. These studies overlap spatially and temporally, allowing synchronous collection of environmental, predator, and prey data and synoptic assessment of their seasonal interactions. The continued decline of apex predator populations has illustrated the fundamental need to understand ecosystem mechanisms and processes at the organismal and population levels. After years of unprecedented and intensive research on Steller sea lions, there is still no clear evidence that nutritional stress, environmental change, or predation are individually linked to their continued declines (NRC 2003). A primary stumbling block has been in determining what mechanisms are expected to control the population’s decline/lack of recovery at the ecosystem, population, individual, and cellular levels. In GAP II, we continue to explore the structure of this system and monitor spatial and temporal changes in its biotic and abiotic components. We will take insights developed in the previous GAP efforts to explore the connections between these components from oceanographic, physiological, and ecological perspectives. While continuing to monitor the structure and variability of the system, we will begin to explore the physical processes, energetic pathways, and physiological mechanisms that link its components. This and future GAP research will explore the interfaces where physical oceanography drives primary productivity, where predators consume their prey, and where captive fish react to controlled environmental conditions. Although originally addressing questions regarding Steller sea lion declines, our GAP questions have broader managerial relevance as well. Ecosystem-based marine resource management relies on understanding both the structural components of the system and the functional mechanisms of their interactions. By monitoring the seasonal distribution and abundance of predators and prey, we are defining their ‘habitats of particular concern’. By tracking oceanographic variability in relationship to zooplankton and fish populations, we are exploring effects of environmental change on primary and secondary production. As a multi-year study, GAP is developing time-series needed to forecast and predict effect of potential natural and anthropogenic perturbations. Ultimately, by considering predators and prey in terms of energetic content and their interactions as energetic exchange, data collected by GAP related research will be used to develop a holistic model of the Kodiak marine ecosystem.

The western stock of Steller sea lions (SSL) has decreased by about 81% over the past 30 years and is now listed as “endangered” under the Endangered Species Act. Evidence suggests links between low juvenile survival and nutrient limitations (i.e. diets of low quantity, quality, and diversity). Diets of SSLs are diverse and include species of primary and secondary importance to commercial fisheries in Alaska. Thus fishing activity in haulout areas is assumed to negativity effect the ability of SSLs to secure food. Based primarily upon assumptions about SSL foraging behavior and prey/habitat use, National Marine Fisheries Service recently implemented legislation that disallows trawl fishing in 10 nmi radii around SSLs haulouts. We hypothesize that the relative composition and abundance of prey species in the diet of SSLs is directly related to availability of prey around critical haulouts in the Kodiak area. The location of Kodiak Island is central to the decline in number of SSLs and the local fishing industry is greatly impacted by the newly imposed no-trawl ‘buffer zones’ around SSL haulouts. In the Kodiak Island region we are proposing to determine seasonal SSL abundance, distribution (aerial surveys – monthly), and diet (scat collection – quarterly). Simultaneously, we will determine temporal (seasons, years) and spatial (10 and 20 nmi) composition, abundance and distribution of prey around five critical haulouts on the eastern side of Kodiak Island. We will compare the use of prey by SSLs to availability of prey both inside and outside of the ‘buffer-zones’ among seasons and years. These data ultimately will be of practical importance to fisheries managers and will provide basic knowledge of predator/prey dynamics in the Kodiak Island region.