• Growing Rhodiola rosea in Unalakleet, Alaska

      Reza, Mosaddeque; Koskey, Michael; Jones, Jenny Bell; Nakazawa, Anthony (2016-05)
      Rhodiola rosea is a medicinal herbal plant that grows naturally in higher altitudes and colder regions in the world including mountainous regions of southwest China and the Himalayas, and the circumpolar North, including Siberia, Iceland, Finland, Norway, Sweden, some parts of Canada, and Alaska. People use its dry roots as tea, put its extract in capsules, and eat it as a vegetable. It helps reduce mild to moderate depression and general anxiety disorder, and it enhances work performance in adverse conditions. It is an adaptogen, that is, it works in the body without affecting any biological function. Because of this, it does not have any side effects like many industrial medicines. Since it reduces depression, it could be helpful to suicidal patients, but more research and studies are needed. Demand for Rhodiola rosea around the world has been increasing steadily. It is relatively inexpensive. It used to be collected from the wild. To meet increasing demands, some countries are growing Rhodiola rosea as an agricultural crop. Alaska has preferred weather and ecosystems to grow Rhodiola rosea commercially. Growing Rhodiola rosea in rural Alaska could bring new sources of income and economic independence. Since the rural Alaskan lands in Unalakleet under consideration have never been used for agriculture, rural Alaskan grown Rhodiola rosea could be certified as organic. This might create a special market. This paper looks at the possibility of growing Rhodiola rosea at Unalakleet, a rural Alaskan village in western Alaska.
    • Grownups: a novel

      Humphrey, Justus Rhodes (2007-12)
      This thesis is a novel. The story centers on three artistic best friends as they shift from carefree college students into stressed adults. Scott, a musician, is reluctantly groomed to take over his parents' business when they retire. Theo, a painter, plans to use his creativity as a graphic designer only to wind up filing paperwork. And Oscar, a writer, discovers that both graduate school and teaching fall short of his dreams. Living far from each other for the first time, they must face life's challenges-including marriage, heartbreak, and disappointment-without one another's support close at hand. Oscar turns these events into fiction and struggles with his emotional response to the process. But he keeps writing, wishing it could change past mistakes
    • Growth and Energetic Condition of Dolly Varden Char in Coastal Arctic Waters

      Stolarski, Jason T.; Prakash, Anupma; Sutton, Trent; Margraf, Joseph; Rosenberger, Amanda (2013-05)
      Dolly Varden char Salvelinus malma are a dominant member of the nearshore Arctic icthyofauna and support one of the largest subsistence fisheries within Arctic coastal communities in Alaska. Despite this importance, numerous aspects of Dolly Varden ecology remain poorly understood, which inhibits efforts to assess the biological consequences of anthropogenic disturbances such as hydrocarbon extraction and climate change within nearshore areas. The goal of this research was to develop and apply new techniques to measure and assess the biological integrity of Dolly Varden populations. To do so, I evaluated the precision of age determination generated from scales, otoliths, and fin rays, developed and validated bioelectrical impedance analysis (BIA) models capable of predicting non-lethal estimates of Dolly Varden proximate content, calculated and correlated retrospective estimates of Dolly Varden growth from archived otolith samples to broad-scale environmental variables, and investigated trends in whole body and tissue proximate content among years and demographics (i.e. reproductive versus non-reproductive individuals). Dolly Varden age determinations can be produced non-lethally using scales for fish up to age 5, while otoliths should be used for fish age 6 and greater. Multi-surface BIA models produced estimates of whole body proximate content with high precision. Retrospective growth analyses indicated growth increased significantly during the early 1980s, and was positively correlated to air temperature, sea surface temperature, and discharge and negatively correlated to ice concentration. Analyses of proximate content suggested that non-reproductive fish contained greater lipid concentrations than reproductive fish. Growth and condition analyses suggest that these metrics vary among years and are a function of reproductive cycles and environmental variability operating at multiple temporal and spatial scales. The adoption of scale-based aging and BIA technology will increase the precision of age-based biological statistics and aid in the detection of change within future Dolly Varden research and monitoring.
    • Growth and maturity of the Pacific razor clam in eastern Cook Inlet, Alaska

      McKellar, Jamie M.; Sutton, Trent; Iken, Katrin; Horstmann-Dehn, Lara; Hardy, Sarah; Erickson, Jack (2014-12)
      In Alaska, the only road-accessible fishery for the Pacific razor clam, Siliqua patula, is located in eastern Cook Inlet, and has been monitored by the Alaska Department of Fish & Game (ADF&G) since 1964. In recent years, a shift has been observed in size, age, and number of clam cohorts in this region, yet little is known about the early life history of razor clams in this region. This study aimed to provide information on length and age at maturity, growth rates, and spawn timing at two beaches in eastern Cook Inlet, Ninilchik and Clam Gulch, in 2009 and 2010. At Clam Gulch, only 20% of the sampled population was reproductive, compared with 83% at Ninilchik. At Ninilchik, clams were reproductive at a smaller size and younger age (p<0.05) than previously documented. The Ninilchik clams grew faster and had a larger size at age (p<0.05) than at Clam Gulch. A body condition index of clams from Clam Gulch was consistently 50% lower than at Ninilchik. Despite the relative proximity (25 km) of these locations, it is possible that environmental conditions may be different, resulting in differences in growth and reproductive output. This information is of special interest to fisheries managers as they address recent declines in the eastern Cook Inlet razor clam population and provides a benchmark for future management decisions.
    • Growth and nutritional development of reindeer (Rangifer tarandus) and muskoxen (Ovibos moschatus)

      Knott, Katrina K. (2004-08)
      Young ruminants must grow and develop digestive function during brief summers in the Arctic. I examined growth and development of nutritional organs in reindeer and muskoxen as neonates (1 d), during transition from milk to forage (30-60 d) and at maturity. Reindeer and muskoxen gave birth to relatively smaller offspring than ruminants from more temperate regions. Costs of small birth mass are likely offset in neonates by an increase of thyroid hormones to enhance thermogenesis and hepatic reserves that provide additional nutrients during early development. Body mass gains during the neonatal period (1-30 d) were associated with well-developed abomasa that allow young to utilize milk immediately after birth. Transition to forage coincided with mass gains of the rumen, small intestine and colon. Digestive morphology also was modified to facilitate fermentation of plants and enhance digestion and absorption of nutrients by 60 days of age. Digestive anatomy of young reindeer and muskoxen also indicated that feeding strategies of adults may be determined from birth. Growth of reindeer and muskoxen, therefore, is dependent upon an endogenous sequence of nutritional development that allow young to take advantage of concentrated milk after birth and time fermentative function to plant emergence at high latitudes. These advances permit young to meet requirements of growth and establish reserves before winter.
    • Growth and post-harvest quality of selected Pacific oysters (Crassostrea gigas) cultured in Kachemak Bay, Alaska, and Puget Sound, Washington, in October of 2009 and June of 2010

      Thomas, Stuart Rendell; Oliveira, Alexandra; RaLonde, Ray; Eckert, Ginny; Langdon, Chris (2012-05)
      The primary objective of this project was to evaluate the growth, biochemical and fatty acid composition, physical and shell characteristics, and basic reproductive development of families of Pacific oysters (Crassostrea gigas) from the USDA-funded Molluscan Broodstock Program (MBP) planted in suspended culture in Kachemak Bay (KB), Alaska, and at an intertidal site in Thorndyke Bay (TB), Puget Sound, Washington. The MBP selects oysters to improve yields, growth, and survival, but little is known about the effects of selective breeding on other biological characteristics of selected oysters. Shell and meat characteristics of oysters from each of the seven highest-yielding MBP families were compared with those from non-selected control families at each site, which were sampled in October of 2009 and in June of 2010. Biometric and growth data, proximate compositions, fatty acid compositions, and basic degree of reproductive development were measured and compared by family, site, and sampling time. Selection improved yield, growth, and survival in MBP Cohort 20 oysters over three years of growout at KB. Colder water temperatures at KB relative to TB inhibited reproductive development, altering the biochemical composition of oysters within sites and between sampling times. Oysters grown at KB were slower growing and smaller when compared to TB, but higher in glycogen, Omega-3, and Omega-6 fatty acids (particularly docosahexaenoic acid: 22:6 Omega 3). Different latitudes and culture types were contributing factors for observed differences in growth, physiology, and composition, resulting in characteristically unique oysters from either site.
    • Growth and Yield of Black Spruce, Picea mariana (Mill.) B.S.Pl., in Alaska

      Rosner, Carolyn; Packee, Edmond; Ping, Chien-Lu; Maich, John C. (University of Alaska Fairbanks, School of Natural Resources and Agricultural Sciences, 2004-08)
      Black spruce, Picea mariana (Mill.) B.S.P., is largely overlooked in Alaska because of its small size and slow growth. Growth and yield information is therefore limited or nonexistent. Presented here are the first polymorphic site index (height-age) curves and height-diameter functions for predicting height and volume for Alaska black spruce. Models are accurate for trees up to 50 feet in height and 8 inches DBH. Predicted stem volumes range from 0.006 ft3 to 21.8 ft3 for trees between 0.5 and 11.5 inches DBH Sampled tree dimensions range from 5.5 to 78.0 feet tall and from 0.4 to 11.0 inches DBH. Sampled breast-height ages range from 49 to 257 years; average age-to-breast-height is 26 years. This research, although limited, also characterizes general stand-level structure and community composition for Alaska black spruce. 60 Permanent Sample Plots (PSPs) representing 20 stands were established throughout the Tanana Valley, with stand inventory conducted according to a consistent protocol. Stand densities range from 137 to 2,907 trees per acre; stand volumes ranged from 8 to 2,507 ft3 per acre. Stand density index values range from 6 to 453. Periodic remeasurement of PSPs will yield valuable information about stand evolution and community type change.
    • Growth dynamics of juvenile yellowfin sole (Pleuronectes asper) and northern rock sole (Lepidopsetta polyxystra) in the eastern Bering Sea

      Williams, Benjamin Charles (2003-12)
      The first five growth zones of 744 yellowfin sole and 512 northern rock sole otoliths were measured from year-classes 1974-1989, to identify patterns of annual growth and sources of temporal variation. Growth patterns were observed graphically and temporal variation was examined by partitioning growth into year and age effects via linear models. Growth and recruitment relationships with biological and environmental variables were explored through correlation analysis and stepwise regression. Results indicate that growth of yellowfin sole and rock sole declined from the late 1970s to the mid 1980s. Yellowfin sole length at age rebounded after 1985, while rock sole length at age continued to decline until at least the early 1990s. Density-dependent factors such as competition during early growth years overshadow the impacts of environmental variables on growth for both yellowfin sole and rock sole, possibly due to the complex oceanographic and atmospheric relationships that exist in the Bering Sea. Recruitment strengths of yellowfin sole and rock sole have significant environmental components suggesting that survival rates may be influenced by environmental conditions. Also, interspecific competition with yellowfin sole may be influencing rock sole recruitment in the eastern Bering Sea.
    • Growth of chum salmon in relation to population abundance and climate in the eastern north Pacific Ocean and the recruitment of pollock in the eastern Bering Sea

      Yasumiishi, Ellen Martinson; Criddle, Keith; Helle, John; Hillgruber, Nicola (2013-12)
      Global climate change is expected to change the distribution and growth of marine species. Therefore, understanding how climate, ocean productivity, and population abundance affect the dynamics of marine species will help predict how growth and recruitment of marine species will respond to future changes in climatic and oceanic conditions. Statistically significant intertemporal correlations have been observed between a variety of environmental factors and recruitment, growth, mortality, and abundance of fish populations. However, because these correlative relationships are not reflective of the actual biophysical processes, the relationships can break down, particularly when used for forecasting. Failure of these simple correlative relationships motivates the search for biological indicators that integrate ocean productivity across ecological dimensions and through time. Measured distances along Chum Salmon (Oncorhynchus keta) scale radii and associated body morphology were used to construct time series of Chum Salmon growth and, by extension, time series of productivity of those ecological domains salmon have exploited. Seasonal and annual marine growth of Chum Salmon from Fish Creek, Alaska and Quilcene River, Washington were examined in relation to population abundances and climate indices, 1972-2004. Final body size at maturity of these Chum Salmon was associated with variation in immature growth incurred while in oceanic waters. Density-dependent effects and climate explained some of the variation in growth but did not account for the entire increase in size at maturity in the mid-1990s. In the Bering Sea, Chum Salmon growth was assessed as an indicator for the recruitment of Walleye Pollock (Theragra chalcogramma) to age-1 in an effort to support an ecosystem-based fisheries management. Chum Salmon growth and the maximum of the monthly sea surface temperature explained 85% of the variation in age-1 Walleye Pollock recruitment. Higher Walleye Pollock recruitment success was associated with the combined effect of a cool late summer and intermediate growth of Chum Salmon. The combination of a physical and biological indicator served as the best indicators for changes in the marine growth of Chum Salmon and for the recruitment of Walleye Pollock.
    • Growth of juvenile Chilkat Lake sockeye salmon in response to density-dependent and environmental factors

      Neil, Jodi C.; McPhee, Megan V.; Adkison, Milo D.; Agler, Beverly A.; Ruggerone, Gregory T. (2018-12)
      Chilkat Lake, in northern Southeast Alaska, is home to a Sockeye Salmon Oncorhynchus nerka population that is an important component in local commercial, sport, and subsistence fisheries, and has been monitored since the late 1960s. The population began declining in the late 1980s, prompting fishery managers to evaluate the production potential of Chilkat Lake to determine if it could be a candidate for enhancement efforts such as fry stocking or lake fertilization. Sockeye Salmon fry were stocked into Chilkat Lake intermittently from 1989 to 2004 in both small- (<50,000) and large-scale (2.6-5.3 million) events. The purpose of this study was to determine whether stocking of fry resulted in decreased freshwater growth due to density-dependent processes. Fish scales from the Alaska Department of Fish and Game's archived collection of adult Chilkat Lake Sockeye Salmon were measured and used as a proxy for fish growth. The objectives of this thesis were to 1) examine changes in juvenile Chilkat Lake Sockeye Salmon freshwater growth over time (1978-2012); 2) determine whether increased density of juvenile fry coupled with simultaneous climate events negatively affected freshwater growth of Chilkat Lake Sockeye Salmon; and 3) determine whether increased density of juvenile fry affected age at smoltification of Chilkat Lake Sockeye Salmon. We hypothesized that high fry density would slow growth and delay smoltification; however, these analyses produced variable results. We did not detect an effect of increased fry density on growth in the first year of fresh water, but found evidence for a subtle, negative relationship between fry density and second year freshwater growth of those fish that delayed migration. We also found that age at smoltification decreased with increasing fry density. Overall, the model results indicated that no factor or combination of factors related to stocking activity or climate consistently affected juvenile Sockeye Salmon scale growth, suggesting either unidentified, equally influential, or confounding mechanisms (e.g., high adult escapement and anomalous weather patterns).
    • Growth of juvenile chinook salmon (Oncorhynchus tshawytscha) as an indicator of density-dependence in the Chena River

      Perry, Megan T. (2012-08)
      In management of Pacific salmon, it is often assumed that density-dependent factors, mediated by the physical environment during freshwater residency, regulate population size prior to smolting and outmigration. However, in years following low escapement, temperature may be setting the upper limit on growth of juvenile chinook salmon Oncorhynchus tshawytscha during the summer rearing period. Given the importance of juvenile salmon survival for the eventual adult population size, we require a greater understanding of how density-dependent and independent factors affect juvenile demography through time. In this study we tested the hypotheses that (1) juvenile chinook salmon in the Chena River are food limited, and (2) that freshwater growth of juvenile chinook salmon is positively related with marine survival. We tested the first hypotheses using an in-situ supplemental feeding experiment, and the second hypothesis by conducting a retrospective analysis on juvenile growth estimated using a bioenergetics model related to return per spawner estimates from a stock-recruit analysis. We did not find evidence of food limitation, nor evidence that marine survival is correlated with freshwater growth. However, we did find some evidence suggesting that growth during the freshwater rearing period may be limited by food availability following years when adult escapement is high.
    • Growth Of Western Alaska And Asian Chum Salmon (Oncorhynchus Keta) In Relationship To Climatic Factors And Inter- And Intraspecific Competition

      Agler, Beverly Ann; Smoker, William; Hagen, Peter T.; Kruse, Gordon H.; Mueter, Franz J. (2012)
      Ocean climate shifts and interspecific interactions with Russian pink salmon and Asian chum salmon are all believed to influence the growth of chum salmon in the North Pacific Ocean. Stepwise generalized least squares regression and Mantel's tests were used to examine factors influencing mean annual growth from adult scales collected during 1962-2008. First-year scale growth was affected by warmer regional temperatures, the North Pacific Index (NH), and reduced ice cover. Significant negative effects of Asian chum salmon abundance were found on third-year growth of five of six age 0.3 populations and three of four age 0.4 populations examined, indicating intraspecific competition. I found a negative correlation with third-year growth, North Pacific annual sea surface temperature (SST), and NM. Effects of interspecific interactions on third-year growth due to Russian pink salmon abundance were smaller than effects of Asian chum salmon abundance and SST. Warmer large-scale SSTs associated with reduced third-year growth contradicted the original hypothesis and suggested that the abundance of Asian chum salmon created a masking effect overwhelming other factors promoting growth. Strong correlations among third-year growth suggested that chum salmon experienced similar environmental conditions in the North Pacific and had overlapping distributions. More synchronous growth was observed among populations from close rivers than distant ones, indicating the importance of regional scale versus oceanwide studies. In the first year, intercircular distance declined then rapidly increased at circuli 5-9, Intercircular distance was similar by gender until the third year when male growth exceeded female growth for all populations except Japan. Back-calculated lengths indicated that fish reach ~494 mm fork length by the third year before returning as age 0.3 adults. Smolts entering the ocean during odd years had greater distances between adjacent circuli the next year, indicating reduced growth in the first year and compensatory growth during the second and third years. Overall, these results suggested possible effects on chum salmon growth due to abundance of Asian chum salmon, and this effect led to a reduction in length of approximately 42 mm, potentially affecting fecundity by 3%. These results contribute to growing evidence of competition among conspecific salmon.
    • Growth of young-of-the-year salmonids in the Chena River, Alaska

      Walker, Robert J. (1983-12)
      Growth of young-of-the-year Arctic grayling (Thvmallus arcticus), chinook salmon (Oncorhynchus tshawytscha) and round whitefish (Prosopium cylindraceum). was examined in the Chena River during 1981 and 1982. Each species exhibited a gradient of growth within the main river; faster growing fish were found downstream. Highest growth rates occurred in Badger Slough, a clearwater tributary that parallels the lower river. Fish condition followed a similar pattern; faster growing fish were heavier at a given size. Between year differences in environmental conditions affected the first appearance, distribution and growth of these species. Growth pattern was reflected on the scales of Arctic grayling. Faster growing fish had a greater number of circuli that were more widely spaced. For fish from the lower river and Badger Slough, the number of circuli formed by the end of the growing year was not significantly different between years. This characteristic may be used to identify Chena River Arctic grayling stocks.
    • Growth physiology of juvenile red king crab, Paralithodes camtschaticus, in Alaska

      Westphal, Miranda J.; Tamone, Sherry; Eckert, Ginny; Siddon, Christopher (2011-08)
      Lack of recovery, following collapse of the Alaskan red king crab, Paralithodes camtschaticus, fishery, has prompted research directed towards rehabilitating the species. To better inform rehabilitation efforts aimed at increasing survival and growth of P. camtschaticus in their first year of life, I compared individual growth of hatchery-raised and wild-caught juvenile crabs in the laboratory and then compared both sets of laboratory individuals with cohorts from the field. To understand molt cycles, hemolymph was collected from age-0 and age-3 crabs to quantify circulating molting hormones (ecdysteroids) and the duration of premolt. Size, growth increment, molt interval, and cumulative molt interval did not differ significantly between hatchery-raised and wild-caught crabs. No consistent differences existed in CL between hatchery, wild-laboratory and field-surveyed juveniles for most months, although spine lengths of hatchery-raised and wild-caught crabs were significantly longer than field-surveyed crabs most months. Patterns of circulating ecdysteroids resembled published profiles for other crustacean species. Peak ecdysteroid levels occurred regularly (approximately 17 d) prior to ecdysis despite varying molt intervals. Age-0 and age-3 juveniles spent approximately 39 % and 32 % of the molt cycle in premolt, respectively. Overall, hatchery-raised and wild P. camtschaticus were markedly similar with respect to growth.
    • Growth Rates Of Calanoid Copepods In The Northern Gulf Of Alaska, And Their Relationships To Temperature, Chlorophyll And Body Size

      Liu, Hui; Hopcroft, Russell (2006)
      The juvenile growth rate and development time of the dominant calanoid copepods in the northern Gulf of Alaska were investigated. The utility of the artificial-cohort method was successfully validated as the most practical approach for estimating copepod growth rates in this ecosystem. The underlying functional responses of growth rates to temperature, food concentration, and body size were thoroughly explored for Neocalanus flemingeri/plumchrus, Metridia pacifica, Calanus marshallae, C. pacificus and Pseudocalanus spp. These results lay the foundation for the calculation of copepod secondary production and ongoing ecosystem modeling activities for the northern Gulf of Alaska, and will contribute to the refinement of global models of copepod growth rates. In general, the rates of copepod growth were negatively size-dependent. However, a positive relationship between growth rate and body size within each stage emerged in response to food climate. The effect of temperature on growth rates was prominent, but confounded with food conditions and body sizes, which also vary with temperature conditions. Copepod growth rates were significantly related to chlorophyll a, and were frequently food-limited, particularly for later developmental stages during the summer. Compared to other co-occurring calanoid copepods, egg-carrying species (i.e. Pseudocalanus) tend to grow slowly to meet their unique life history strategy. Statistically, more variability in temperature corrected growth rates can be explained by composite nonlinear models that incorporate development stage and body size into the traditional Michaelis-Menten relationship. The species-specific comparisons of the measured growth rates with those predicted by global models of copepod growth suggested more direct measurements of copepod growth rates in various ecosystems are required for fully appreciating the global patterns of copepod growth. Caution should be used in the widespread application of those models for estimating copepod secondary production, especially in polar and sub-polar waters.
    • Growth response of lutz spruce saplings to the removal of a herbaceous competitor and the application of fertilizer in Southeast Alaska

      Dickson, Emily; Barber, Valerie; Sparrow, Stephan; Harris, Norman (2014-08)
      Herbaceous competitor species such as fireweed can impact future survival and growth of Lutz (Picea x lutzii Little, Pinaceae) spruce saplings. Fertilizer is applied to crop trees in order to supply more nutrients to promote growth. However, fertilizer benefits competitor species as well. Literature regarding the impacts of competition for resources between fireweed and spruce saplings are lacking, but the impacts of resource competition on seedling growth and fireweed are documented as significant. Seedlings are distinguished from saplings by differences in height and/or diameter. In order to test the influence of both competitor species and added fertilizer, we analyzed growth response of Lutz spruce saplings to fireweed removal and applied fertilizer through treatments and controls using a two by two factorial experiment. Results revealed that fireweed removal had a positive effect on sapling growth response, while added fertilizer alone showed no effect on sapling growth response. I found a strong, positive correlation between soil moisture and fireweed cover. I also found a strong, positive relationship between sapling growth and soil moisture as well as sapling growth and fireweed cover. This study demonstrates that spruce saplings positively responded to fireweed removal compared to the application of fertilizer. More importantly, the overall conclusion is that when saplings are not N limited soil, moisture is the driving factor in sapling height growth. The long-term effects of harvesting an efficient nitrogen competitor species are not well known and could be detrimental to future site fertility.
    • Growth, foraging behavior and distribution of age-0 Arctic grayling in an Alaskan stream

      Dion, Cheryl Ann (2002-12)
      I evaluated the ability of three models to relate habitat characteristics to habitat quality for age-0 Arctic grayling Thymallullus arcticus in an Alaska stream. A temperature-based growth model made accurate predictions, showing it can reliably assess thermal habitat quality. Deviations between predicted and observed growth were useful because they identified the timing of possible critical periods, when competition for food or space may cause density-dependent mortality and emigration. A foraging model consistently overestimated the mean prey size of fish, showing that such models need further work before then can accurately assess food availability from invertebrate drift. A habitat selection model accurately predicted small fish would occupy the stream margins and the ontogenetic shift into faster, deeper water, but its detailed predictions for larger fish were not very precise. These models were useful tools for assessing habitat quality and gave insight into possible interactions between habitat characteristics and population dynamics.
    • Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus)

      George, John Craighead (2009)
      This thesis describes investigations on bowhead whales (Balaena mysticetus) conducted over the past three decades, specifically on age, growth, morphology and energetics. The examined whales were harvested by Inupiat Eskimo whale hunters primarily in Barrow, Alaska. Bowheads are robust cetaceans reaching 19 m in length and inhabit the ice-covered waters of the circumpolar Arctic. They have the thickest blubber (? 35 cm) of any cetacean and the longest (>4 m) and most extensive baleen apparatus. Bowheads are ~4 m at birth and grow rapidly to ~8 m in their first year; they then experience a 2-3 year growth pause in both body length and mass. However the baleen continues to grow during this period. Sex differences are minimal but adult females tend to grow longer than males and males have larger pectoral limbs. Based on several lines of evidence, bowheads may routinely live to 150 years and thereby the longest-lived mammal. The recovery of 19 th century stone weapons from recently harvested whales confirms these age estimates. Age was estimated for 48 whales using the aspartic acid racemization technique, based on intrinsic changes of aspartic acid within the eye lens. The age at sexual maturity for bowheads occurs in the mid-20s. All harvested whales examined showed strong thermal gradients through their blubber (dermis and epidermis). A similar thermal gradient was evident through the muscle which is atypical of most terrestrial mammals. The deep body temperature averaged 33.8�C (SD=0.83, N = 28) which is lower than in other non-hibernating eutherian mammals. I did not see elevation of body temperatures in chased whales -- in fact these whales had slightly lower core temperatures. Resting metabolic rates for whales were estimated using a heat-loss technique. The thermal conductivity of the blubber for 5 whales averaged about 0.23 Wm-1K-1; similar to that of other whales and marine mammals. Heat flux rates varied highest to lowest as follows: palatal rete, flukes, tongue and lowest for the thorax and flippers. The resulting metabolic rates were much lower (~ 1/3) than predicted by the Kleiber regression. These investigations suggest that bowhead whales are unique among mammals in several respects such as: (a) following weaning they appear to lose weight over a period of 2-3 years and grow little in body length, (b) resting metabolic rates and body temperatures are lower than in other cetaceans. Their extensive blubber likely buffers bowheads against high variability in primary and secondary productivity in arctic seas.
    • Growth-increment formation using otoliths and scales of juvenile chinook salmon

      Walker, Brian Michael; Sutton, Trent; Adkinson, Milo; McPhee, Megan (2013-12)
      Freshwater growth of juvenile Chinook salmon Oncorhynchus tshawytscha influences survival and recruitment to the adult population. Retrospective analysis is used to measure salmon growth at previous ages, with fish size and growth assumed to be accurately reflected by otolith increments and scale circuli. I conducted a 122-d laboratory experiment to validate the relationship among body size, growth, and width to daily otolith growth increments and scale circuli in juvenile stream-type Chinook salmon. Fish total length was found to be proportional to otolith axis length (r² = 0.209, p < 0.001), otolith diameter (r² = 0.667, p < 0.001), and scale radius (r² = 0.538, p < 0.001). Somatic growth was accurately reflected by growth in otolith axis length (r² 0.65, p < 0.001) and growth in scale radius (r² = 0.449, p < 0.001). My study validated the assumption that fish body size and growth are reflected by otolith and scale size and growth- increment formation. The findings of my study can be used to ascertain body size at previous ages, which will help managers detect threshold sizes, examine the strength of size-selective mortality, and determine how growth rate affects smolt migration, early marine survival, and duration of ocean residency.