• Effects of variable maternal diet conditions on the reproductive success and development of the California sea cucumber (Parastichopus californicus)

      Regula-Whitefield, Charlotte Marie; Hardy, Sarah Mincks; Oliveira, Alexandra; Iken, Katrin; Gradinger, Rolf; Hervey, H. Rodger (2016-12)
      Anthropogenic and natural climate change is altering the biology and ecology of marine organisms, which can be reflected in the supply of primary production that provides food for consumers. Primary producers differ in their biochemical composition, and marine food webs are thus based on specific combinations of producers that provide key nutrients such as dietary fatty acids (FA). Some FA cannot be synthesized by marine invertebrates, and must be acquired directly from diets. Reproductive processes in marine invertebrates are often timed to correspond with seasonal patterns in primary production, such that dietary FA and other nutrients can be partitioned to eggs to provide energy for cell division and biomolecules needed for membrane development. My dissertation investigates the consequences of changing patterns in primary production by examining the effects of maternal diet on reproductive fitness of a deposit feeder, and provides information to support the management and continued captive culturing of the commercially harvested Parastichopus californicus (California sea cucumbers). In chapter 1, I describe a novel live-spawning method and quantify basic reproductive parameters for P. californicus. Peak spawning in the Southeast AK population was about two months earlier and three times smaller than previously observed in British Columbia, Canada. Live-spawned captive females produced more viable eggs and strip-spawned females produced higher fecundity rates. These findings are relevant for the management of commercially harvested populations of P. californicus because they more accurately define spawning seasons, and provide a reliable method to spawn captive animals for further aquaculture development. In chapter 2, I present the results of feeding experiments that explore the effects of two mono-specific algal feeds with different FA profiles on female reproductive output and pre-feeding larval fitness. Females fed with the green alga Tetraselmis sp. had higher fecundity, but there was reduced larval survival relative to females that were fed the diatom Thalassiosira sp. Similar rates of larval development were recorded in both feed treatments. Significant differences were observed in the abundance of FA 20:5ɷ3 (EPA), 22:3ɷ6 (DHA), 12:0, 16:0, and 18:0 FAs in eggs and female gonads between the two feed treatments. In chapter 3, I used field collections in Southeast AK to assess temporal patterns feeding behavior and diet, and examined tissue-specific patterns in total lipid and FA storage and utilization, in in situ populations of P. californicus. All tissue ratios (percent of each tissue relative to the total body mass) varied significantly among collection dates. Tissue and gut content total lipid content also varied significantly among collection dates, except for muscle tissue. Shell debris and terrestrial debris were abundant in all guts regardless of collection date. FA composition differed significantly among females with different gonad maturation periods in skin, viscera, and gonads, suggesting the use of lipids stored in skin and viscera for gonad development. These results further the understanding of dietary factors affecting reproductive fitness in deposit feeders by demonstrating the importance of diet and lipid storage to gonad development.
    • The effects of water temperature on the seasonal distribution and growth of walleye pollock, Theragra chalcogramma (Pallas), in the southeast Bering Sea

      Chen, Lih-Feng (1983-05)
      The distribution and growth of walleye pollock, Theragva ohalaogvamna (Pallas), were studied in relation to bottom water temperatures, in an area between latitude 54°30'N and 57°30'N and longitude 160°W and 170°W, from the data collected from 1976 to 1980. The annual variations of bottom temperature distribution, including mean temperature, are described. It is found that temperature boundaries regulate spawning aggregation areas and feeding distribution of adult pollock. Young pollock were distributed in a wider temperature range and revealed a clearer feeding migration pattern than the adults. The weight growth for walleye pollock aged 2 to 4 was determined. The growth rate varied with age, sex and year. The relative growth rate was related to the initial weight of the fish and the mean temperature. Additional seasonal variations in the length-weight relationship and condition factor were observed.
    • Endocrine And Immune Profiles Of Immature Pinnipeds

      Keogh, Mandy Jean; Atkinson, Shannon; Castellini, Michael; Hellman, Tuula; Ortiz, Rudy; Runstadler, Jonathan (2011)
      There is increasing interest in assessing the health of individuals and populations of pinnipeds found in the North Pacific, primarily due to population declines leading to conservation concerns. This study assessed the "health" of animals by quantifying hormones associated with fat mass (leptin), lipid and water metabolism (cortisol and aldosterone), and growth and metabolism (thyroxine and triiodothyronine) as well as circulating total and differential leukocyte counts and in vitro proliferation of peripheral blood mononuclear cells (PBMC). Body mass and condition are influenced by an individual's disease and nutritional state. Glucocorticoids are known to affect the immune system and may be stimulated by a multitude of factors. I hypothesized that age or body mass would influence leukocyte counts, PBMC proliferation, and hormone concentrations in Steller sea lion (Eumetopias jubatus) pups and that the response of cortisol to an acute stressor would impact immune parameters in juvenile harbor seals (Phoca vitulina ). Further, given the inherent requirements of disturbance and animal handling necessary for sampling pinnipeds, the impact of these activities on endocrine and immune profiles was assessed. Total white blood cell (WBC) counts, neutrophil counts and T cell proliferation decreased with increasing age in Steller sea lion pups. However, no relationship between body condition index and circulating concentration of hormones quantified was detected. Circulating concentrations of cortisol, thyroxine, and triiodothyronine were influenced by the rookery disturbance. However, the variation attributed to the disturbance was low and did not alter total or differential WBC counts or in vitro proliferation of PBMC. In harbor seals, cortisol and aldosterone concentrations increased following an acute stressor which resulted in a stress leukogram. Total WBC decreased driven primarily by the decrease in neutrophil counts with simultaneous increase in lymphocytes leading to an overall decrease in neutrophil to lymphocyte ratio. These findings highlight the endocrine system's influence on the immune system in immature pinnipeds.
    • Energetics of arctic Alaskan fishes: carbon isotope evidence

      Ziemann, Paul J. (1986-12)
      The natural abundance of carbon isotopes were used to investigate the energy requirements of arctic aquatic consumer organisms. A mathematical model was developed that describes the relationship between the rate of consumer isotope turnover rates of growth and metabolism, and the utility of the model for calculating energy requirements from seasonal changes in consumer isotopic composition was demonstrated in laboratory experiments and with field data. The energy requirements of anadromous fishes, which were the major consumers studied, could not be determined using the isotopic data. Instead, the requirements were calculated using biochemical data and rates of growth and oxygen consumption, and were about 2.6-6.0 kcal day⁻¹ in the summer and 0.4-1.2 kcal day⁻¹ in the winter. Seasonal changes in lipid and protein contents indicate that anadromous fishes cannot find enough food during the winter to supply their energy requirements, and that about 50% of the energy needed comes from the metabolism of tissues accumulated during the summer. The relative importances of marine and freshwater food webs in supplying the energy requirements were determined by comparing the seasonal isotopic components of anadromous fishes to the isotopic compositions of fish that are permanent residents in each environment. It appears that anadromous fishes that overwinter in the Coleville River (the largest river on the Alaska North Slope) depend almost entirely on the marine environment for their energy, whereas those that overwinter in Canada's Mackenzie River rely on both marine and freshwater habitats.
    • Environmental controls of fish growth in the southeast Bering Sea

      Palmer, Michael Collins (2003-08)
      Environmental controls of fish growth in the Bering Sea were investigated by examining growth increments and length-at-age. A sea ice-initiated conceptual model of growth that differentiates between food and water temperature controls was proposed. The timing of ice retreat in the region was hypothesized to control food availability by influencing the fate of primary production and inversely affecting prey availability in pelagic and benthic environments. The extent and persistence of ice coverage was hypothesized to influence shelf water temperatures through' cold pool' development. Utility of the conceptual model was assessed through regression and correlation analyses of the growth of two representative pelagic feeding species, walleye pollock and Pacific herring, and two benthic feeders, yellowfin sole and rock sole. The usefulness of herring and rock sole as indicator species of their respective feeding guilds is lessened due to feeding location and diet breadth, respectively. Food availability was shown to be the primary control of fish growth as evidenced by the growth model results of pollock and yellowfin sole and inverse size-at-age time series of these two species. The ecosystem implications of differential fish growth were assessed through investigation of the relationship of growth to condition factor and recruitment.
    • Estimates of primary production sources to Arctic bivalves using amino acid stable carbon isotope fingerprinting

      Rowe, Audrey G.; Wooller, Matthew; Iken, Katrin; O'Brien, Diane (2018-12)
      Benthic invertebrates are a crucial trophic link in Arctic marine food webs. However, estimates of the contribution of primary production sources sustaining these organisms are not well characterized. Potential sources could include sinking particulate organic matter from sea ice algae and phytoplankton, terrestrial organic matter eroded from the coastal environment, macroalgal material, or microbial organic matter. Proportions of these sources could also be significantly altered in the future as a result of environmental change. We measured the stable carbon isotope values of essential amino acids in muscle tissue from two common bivalve genera (Macoma spp. and Astarte spp.) collected in Hanna Shoal in the northeastern Chukchi Sea, considered an Arctic benthic hotspot. We used stable isotope mixing models in R (simmr) to compare the stable carbon isotope amino acid fingerprints of the bivalves to a suite of amino acid source endmembers, including marine phytoplankton, brown and red macroalgae, bacteria, and terrestrial plants, to estimate the proportional contributions of primary production sources to the bivalve species from Hanna Shoal. The models revealed relatively high contributions of essential amino acids from phytoplankton and bacteria averaged across both species in the region as a whole. We also examined whether stable carbon isotope fingerprints could be measured from essential amino acids preserved in bivalve shells, which could then allow proportional contributions of food sources to be estimated from ancient bivalve shells, allowing source estimates to be extended back in time. To investigate this, we measured the stable carbon isotope values of essential amino acids in a suite of paired modern bivalve shells and muscle from Macoma calcarea from the Chukchi Sea. These analyses revealed a correspondence between the fingerprints and mixing model estimates of the dominant primary production source of essential amino acids derived from analyses of these two tissue types. Our findings indicate that stable carbon isotope amino acid fingerprinting of marine bivalves can be used to examine dominant organic matter sources in the Arctic marine benthos in recent years as well as in deeper time.
    • Estimating ¹³C and ¹⁵N turnover rates in the Arctic amphipod Onisimus litoralis: implications for analysing the transfer of sea ice production to under-ice fauna

      Nielson, Mette R. (2006-12)
      The Arctic amphipod Onisimus litoralis migrates from the seafloor to the sea ice to graze on ice algae, a rich food source during the Arctic spring, resulting in complex trophic dynamics. I assessed the effect of temperature and season on the rate of change in stable isotopic composition of amphipods by simulating a diet switch in the laboratory using amphipods collected near Barrow, Alaska in spring and autumn 2004. Additionally, the proportional contributions of food sources to the amphipods' diet in the field were estimated. Isotopic change occurred faster in spring with half-lives of 13.9 (1°C) and 18.7 (4°C) days for carbon and 22.4 days for nitrogen compared to autumn rates of 77 (carbon) and 115 days (nitrogen). Temperature did not have a significant effect on turnover. Change occurred primarily through metabolic turnover (versus growth-related dilution) and was responsible for 84-89% of the change in carbon and 67-77% of the change in nitrogen in both seasons. A two-source mixing model estimated that ice-derived biota contributed 59 (±17)% to the amphipods' diet in May. These data show that the rate of isotopic change can vary temporally for a single species, highlighting the importance of experimental work for interpreting stable isotope field-data.
    • Evaluation of prey composition and nutritional value of diets of free-ranging harbor seals (Phoca vitulina) from Tugidak Island

      Geiger, Gretchen L.; Atkinson, Shannon; Carpenter, James; Horstmann-Dehn, Larissa; Wynne, Kate (2012-12)
      Changes in climate can cause shifts in ecosystem structure that can affect quantity or quality of prey available to predator populations. Due to sex or age-specific behaviors of predators, certain classes within a population may be more severely impacted by changes in their diet. This study evaluated prey composition and nutritional value of summer diets of harbor seals (Phoca vitulina richardii) from Tugidak Island, Alaska from 2001-2009. The MIXIT-WIN program was used to estimate the nutritional value of average harbor seal diets. Changes in relative abundance of certain prey species were correlated to sea surface temperature anomalies. Despite changes in prey composition, the nutritional value of the average harbor seal diet did not change. Fecal corticosteroid metabolite profiles were analyzed to identify age and sex of individual harbor seals from scats. Profiles obtained from a known adult male harbor seal could be differentiated from those of known adult female and juvenile male seals. Similar profiles were observed in unknown age and sex samples. Even though diet diversity differed between these groups, the nutritional quality of consumed diets was not significantly different. Tugidak Island harbor seals have flexible diets allowing them to capitalize on available prey to maintain their nutritional intake.
    • An examination of hydrography and sea level variability in the Gulf of Alaska

      Kelly, James Bruce; Weingartner, Thomas; Simmons, Harper; Kowalik, Zygmunt (2015-05)
      This thesis summarizes a detailed analysis of Seward sea level (SSL) in the Gulf of Alaska (GOA) and hydrography at oceanographic station GAK1 along the oceanographic monitoring line outside of Resurrection Bay, Alaska. SSL variability was examined with respect to forcing by tides, sea level pressure (SLP), wind, the steric contribution due to water column variations in temperature and salinity, and several climatic indices. In addition, multi-decadal trends in sea level and hydrography were also examined. The period of analysis spans 1970 -2010. Tidal motion (periods < 1day), account for ~97% of the total sea level (SL) variance while SLP variations, induced by the inverted barometer effect, account for ~2% of the total variance. After removing these influences, along-shore wind stress and sea level are highly coherent for the 2 - 60 day subtidal period range and account for ~40 - 50% of the SSL variance over these timescales. The steric contribution, based on the geopotential height referenced to 200 m (GH200), is also coherent with SSL, but it only accounts for ~10% of the SSL variance at these timescales. The along-shore wind stress-SSL coherence varies seasonally and is greatest in winter when winds are strongest and smaller in summer when wind variability is reduced. The annual cycle in SSL is coherent and in-phase with GH200. The latter is primarily controlled by the annual cycle in GOA coastal freshwater discharge and its effect on coastal salinities. SSL variations are also significantly correlated with the Pacific Decadal Oscillation (PDO) and the Southern Oscillation Index (SOI). Over the 40-year record examined here SSL shows a decreasing trend due to continental rebound. There are also statistically significant linear long-term trends in temperature and salinity as measured at GAK1. These trends indicate that the upper 100 m is warming at ~0.20 oC decade-1 and at 0.15 oC decade-1 between 100 - 200 m. Surface salinities are decreasing at 0.15 decade-1, while salinities between 100 and 200 m are increasing by 0.025 decade-1. The surface salinity trends are consistent with an increase in coastal freshwater discharge due to increased glacial ablation and increased precipitation. In aggregate, these trends indicate that the GOA shelf has become more stratified over the past 40 years.
    • Factors affecting estuarine populations of Nereocystis luetkeana in Kachemak Bay, Alaska

      Chenelot, Héloïse Anne Claude (2003-12)
      Nereocystis luetkeana forms extensive kelp beds in Kachemak Bay, Alaska. Salinity and turbidity gradients apparently regulate kelp bed distribution throughout this estuary. The beds are large at the entrance of the bay, only solitary stands occur in the inner bay, and no kelp is found at the head of the bay. The role of salinity and turbidity on Nereocystis sporophyte growth was investigated by performing reciprocal transplants among three beds along the bay axis and regularly measuring stipe growth. The effects of salinity and light on spores were studied in the laboratory by recording sinking tendency, settlement success, germination success, and germ tube length under different salinity and light levels. Grazing effects of Lacuna vincta impacted the survival of Nereocystis transplants in-situ and on plants of different age classes in the laboratory. Overall, this study suggests a possible negative estuarine effect on sporophytes transplanted from the outer to the inner bay and on certain aspects of spore development. Herbivory pressure had significant localized effects on Nereocystis survival and was most pronounced on juvenile plants. The dynamics of Nereocystis kelp beds in Kachemak Bay results from large-scale environmental factors and local-scale biological processes.
    • Factors influencing zooplankton populations in Alaskan sockeye salmon (Oncorhynchus nerka) nursery lakes: insights from limnological and paleolimnological analyses

      Sweetman, Jon N.; Finney, Bruce; Barry, Ronald; Hughes, Nicholas (2001-08)
      The relative importance of sockeye salmon, invertebrate predators, and other environmental factors in structuring the size and abundance of zooplankton populations was examined in a series of 23 lakes from southern Alaska. Zooplankton abundance was strongly related to sockeye density, along with nutrient availability and alkalinity. The mean size of Bosmina longirostris, the dominant herbivorous cladoceran, was positively correlated with the abundance of the predatory copepod, Cyclops columbianus. Changes in the size and abundance of Bosmina remains over the past 300-500 years were then determined for sediments from two lakes on Kodiak Island, Alaska. The zooplankton communities showed varying responses to past changes in salmon populations, resulting from relative changes in the magnitude of adult salmon-derived nutrient loading and in predation pressure from juvenile sockeye and cyclopoid copepods. Knowledge of how various factors impact zooplankton can have important implications for the effective management of sockeye within these lake systems.
    • Fatty acid profiles of Alaskan Arctic forage fishes: evidence of regional and temporal variation

      Dissen, Julia; Hardy, Sarah; Horstmann-Dehn, Lara; Oliveira, Alexandra (2015-08)
      Fatty acids, the main components of lipids, are crucial for energy storage and other physiological functions in animals and plants. Dietary fatty acids are incorporated and conserved in consumer tissues in predictable patterns and can be analyzed in animal tissues to determine the composition of an individual's diet. This study measured the variation in fatty acid profiles of three abundant Arctic forage fish species, Arctic Cod (Boreogadus saida), Canadian Eelpout (Lycodes polaris), and Longear Eelpout (Lycodes seminudus) across multiple years (2010-2013) and geographic locations (Beaufort and Chukchi seas). These fishes are important prey items of marine mammals, sea birds, and predatory fishes, and as such they serve as a critical trophic step connecting lower trophic-level production to higher level predators. Analyzing forage fish fatty acid profiles across multiple years and geographic locations can provide insight into system-level trends in lipid transfer through the Arctic ecosystem. Fatty acid profiles differed among species, with Arctic Cod having higher concentrations of pelagic zooplankton indicator fatty acids, and Eelpout species containing higher concentrations of indicators for benthic prey. While the two Eelpout species displayed major overlap in fatty acid profiles, differences in individual fatty acids may represent niche separation between Canadian and Longear Eelpout in the Beaufort Sea. In addition to variation between species, fatty acid profiles also differed in Arctic Cod between the Beaufort and Chukchi seas, and among collection years. High lipid content and energy-rich fatty acid classes observed in Chukchi Sea Arctic Cod relative to the Beaufort Sea Arctic Cod may indicate favorable feeding conditions in this region over the years sampled, and high energy density of Arctic Cod as prey. Despite the within-species variation observed, the results of this study suggest that Alaskan Arctic forage fish with different foraging ecology can be distinguished based on fatty acid profile, which could be useful in studies that use fatty acid data to characterize diets of top predators.
    • The feeding, movement, and growth of pink salmon, Oncorhynchus gorbuscha, fry released from a hatchery in Prince William Sound, Alaska

      Urquhart, David Lindsay (1979-12)
      As part of a study that investigated the ability of Prince William Sound to support large numbers of juvenile salmon, the movements, feeding, and growth of pink salmon, Oncorhynchus gorbuscha, fry released in the springs of 1977 and 1978 from the Port San Juan hatchery, are described. Fry were released in Sawmill Bay but preferred the waters of adjacent Elrington Passage where they remained for up to two months. Nursery areas in the Passage established by the fry in 1977 were not occupied to the same degree in 1978. Fry fed initially on epibenthic harpacticoid copepods but soon switched to feeding on calanoid copepods. Fry growth rates and diet are comparable with results of other studies. Fry behavior affected sampling and may account for between-year differences detected in growth. Weather, food abundance, and the condition of out-migrants may also account for between-year differences in fry behavior and growth.
    • Fifty years of Cook Inlet beluga whale ecology recorded as isotopes in bone and teeth

      Nelson, Mark A.; Wooller, Matthew J.; Iken, Katrin; Quakenbush, Lori T. (2017-12)
      Beluga whales (Delphinapterus leucas) are found across the Arctic and Subarctic in seasonally ice covered waters. Five stocks of beluga whales are associated with the waters near Alaska for at least part of the year and four of those five stocks are abundant and commonly hunted by Alaskan Natives. The belugas resident in Cook Inlet are also an important cultural and subsistence resource to Alaskan Natives in the area, but a ~50% decline in abundance in the 1990's led to the stock being designated as depleted under the Marine Mammal Protection Act in 2000 and listed as endangered under the Endangered Species Act in 2008. Numerous studies of beluga whales in relation to stranding events, predation (killer whales), parasitism, disease, contaminants, and other potential population threats have not identified the reason for their inability to recover. Changes in diet have been considered, but are difficult to study because observations of feeding in muddy water and beluga stomachs are difficult to obtain. To investigate the past feeding ecology of beluga whales from Cook Inlet I sampled bone and teeth for isotopic analyses. I sampled bone from 20 individuals that died between 1964 and 2007 for stable carbon and nitrogen isotope analysis (values expressed as δ¹³C and δ¹⁵N values). I also micro-sampled annual growth layer groups in the teeth of 26 individuals representing the years from 1962 to 2007. Bone and tooth data showed a general decrease in δ¹³C and δ¹⁵N values over time. The δ¹³C values from analyses of growth layer groups declined from -13.4‰ to -16.2‰ and δ¹⁵N values declined from 17.2‰ to 15.4‰. Although these values are consistent with a change in feeding ecology over time, the magnitude of the decrease in δ¹⁵N values (~2‰) is insufficient for a full trophic level shift (~3‰).The relatively large decrease in the δ¹³C values over the same time period (~3‰), however, is much greater than a full trophic level shift (~1‰) and suggests an increase in prey associated with freshwater, which typically have lower δ¹³C values than prey associated with marine water. To test this hypothesis I analyzed the strontium isotope composition (⁸⁷Sr/⁸⁶Sr ratios) of growth layer groups in teeth from a sub-set of individuals. The resulting ⁸⁷Sr/⁸⁶Sr ratios trended away from the global marine signature (0.70918) over time and toward the more freshwater signatures measured in rivers flowing into the upper reaches of Cook Inlet. These results indicate that the diet of Cook Inlet beluga whales has changed over time. This could be from feeding on different, more freshwater derived prey species, or from feeding on the same species, but on individuals from locations with a more freshwater influence. Both of these interpretations are consistent with population survey data indicating a retraction in beluga range into the upper reaches of Cook Inlet. This study presents the first evidence of a long term (~50 years) change in Cook Inlet beluga whale feeding ecology. The consequences of this change toward more freshwater-influenced prey, and how this change relates to Cook Inlet beluga whales' decline or recovery remains unknown. However, to better examine this change in feeding ecology a follow-up study will; 1) develop a strontium isoscape for the Cook Inlet watershed; 2) analyze more teeth to better analyze changes in feeding ecology by demographic group (sex, age); and 3) analyze growth layer groups from Bristol Bay beluga teeth for a comparison with Cook Inlet belugas to determine if the changes represent an ecosystem change within Cook Inlet or a broader scale change affecting another region. This study builds towards a better understanding of the changes in Cook Inlet beluga feeding ecology and will help to determine if changes in diet could be a factor in their recovery.
    • Foraging Ecology And Nutritional Stress Of Tufted Puffins (Fratercula Cirrhata) Inferred From Stable Isotopes, Fatty Acid Signatures, And Field Endocrinology

      Williams, Cory T.; Buck, C. Loren (2008)
      Prey availability has a major impact on the reproductive output of seabirds, yet information on seabird diets throughout the breeding season is often lacking. Although reduced prey availability is known to affect the growth and survival of nestling seabirds, few studies have demonstrated similar effects on indices of adult body condition. I used stable isotopes and fatty acid (FA) signatures to investigate seasonal and age-related variation in the foraging niches of tufted puffins (Fratercula cirrhata). I conducted captive feeding experiments to determine whether inferences based on these techniques are affected by moderate food restriction during growth. I also examined how adult puffins prioritize the competing goals of maximizing the growth rate of their offspring and maintaining their own condition, as measured by body mass and by the stress hormone, corticosterone (CORT). Food restriction during nestling growth affected adipose tissue FA signatures and resulted in blood that was depleted in 15N and 13C relative to well-fed controls. However, effects of nutritional restriction on delta 15N, delta13C, and FA signatures were small compared to variability in prey, indicating physiological effects do not preclude use of these techniques as dietary tracers. Stable isotopes and FA signatures of free-living adults indicated foraging niches changed over the course of the breeding season. Stable isotopes suggest chick-rearing adults and nestlings feed at the same trophic level while FA signatures indicate that parents feed nestlings a diet different from their own. Body mass of adult puffins declined between incubation and chick rearing periods. For females the magnitude of mass decline did not differ between years, whereas for males the decline was greater in the year where young puffins fledged at a lower mass. In a separate analysis, baseline CORT values of adults of both sexes did not differ between years, but were lower than those observed in a separate study area during two consecutive years with low rates of nestling growth and survival. Assuming elevated CORT and reduced body mass impact survival and/or future fecundity, these results suggest the cost of reproduction may be higher for those adults able to fledge young in years characterized by low productivity.
    • Foraging patterns of northern fulmars in Alaska inferred from fatty acid signature analysis

      Wang, Shiway W. (2005-12)
      Diets of Northern Fulmars (Fulmarus glacialis) in the North Pacific are poorly known, and thus relationships of fulmars to supporting food webs and their potential sensitivity to ecosystem variability, such as that driven by a changing climate, also are uncertain. I employed a new technique, fatty acid (FA) signature analysis, to examine dietary differences among fulmars at three colonies in Alaska. I predicted that 1) signatures of adipose tissue and stomach oils would differ because the time scale each depot reflects differ and/or because adipose tissue FAs may be influenced by predator metabolism, while stomach oil FAs may be influenced by differential uptake; 2) fulmar diets would differ between colonies located in distinct oceanographic settings, which create unique habitats for prey assemblages; 3) diets would differ temporally within colonies because of inter-annual variability in the physical environment resulting in variation of prey FA signatures; and 4) diets of adult fulmars and their chicks would be similar because they feed by regurgitation. I found that FA signatures of adipose tissue were significantly different than those of stomach oil; there were conspicuous spatial and temporal differences in adipose tissue signatures; but diets of adults may differ from those of chicks.
    • Freezing tolerance and survival experiments with various intertidal organisms from Kachemak Bay, Alaska

      Patterson, Heather Kristine (2004-08)
      Intertidal organisms at high latitudes experience multiple stresses created by freezing, including ischemia, free water reduction, and distortion and destruction of cells, and in response have adapted behavioral and physiological solutions. This study examined the response of intertidal organisms in Kachemak Bay, Alaska to freezing through laboratory experiments and field studies. Mytilus trossulus, Balanus glandula, Protothaca staminea and various limpets (Lottidae) survived freezing conditions to -10 and -20°C, depending on the season. Mytilus trossulus and B. glandula survived multiple freeze events at -10°C. Seasonal freeze response was not induced by exposure to low air temperature in M trossulus. Exposure to O⁰C was not fatal to any of the species studied: M trossulus, B. glandula, P. staminea, limpets, Fusitriton oregonensis, Katharina tunicata and Leptasterias hexactis. Preliminary results suggest that M trossulus and P. staminea have an ice nucleator. Freezing avoidance may be one cause for the differences seen in seasonal distribution patterns of F. oregonensis, Nucella lima, Onchidella borealis, Siphonaria thersites and Littorina sitkana. The current study demonstrated that intertidal organisms in this region exhibit differing responses to freezing. Some organisms survive freezing conditions by freeze tolerance, while others may avoid it by moving lower in the intertidal.