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  • If you choose not to decide... Alaska’s budgeting process in 2023

    Wright, Glenn (eScholarship, University of California, 2024)
    Alaska in 2023 is experiencing the first results of the new election system—the top-four all-party primary and Ranked Choice Voting. So far, that system seems to be generating results consistent with what advocates expected; a more moderate and collegial policy-making environment, and possibly even more sensible budgetary policy. This, coupled with relatively strong (though declining) oil prices, and abundant sovereign wealth led to a relatively low-drama, low-conflict budgeting process in spring 2023, as well as relatively moderate budgeting outcomes.
  • Increasing multi-hazard climate risk and financial and health impacts on northern homeowners

    Schwoerer, Tobias; Schmidt, Jennifer I.; Berman, Matthew; Bieniek, Peter; Farquharson, Louise M.; Nicolsky, Dmitry; Powell, James E.; Roberts, Rachel; Thoman, Rick; Ziel, Robert (Springer Nature, 2024-03)
    Currently, more than half of the world’s human population lives in urban areas, which are increasingly affected by climate hazards. Little is known about how multi-hazard environments affect people, especially those living in urban areas in northern latitudes. This study surveyed homeowners in Anchorage and Fairbanks, USA, Alaska’s largest urban centers, to measure individual risk perceptions, mitigation response, and damages related to wildfire, surface ice hazards, and permafrost thaw. Up to one third of residents reported being affected by all three hazards, with surface ice hazards being the most widely distributed, related to an estimated $25 million in annual damages. Behavioral risk response, policy recommendations for rapidly changing urban environments, and the challenges to local governments in mitigation efforts are discussed.
  • Responses of chlorophyll a content for conchocelis phase of alaskan porphyra (bangiales, rhodophyta) species to environmental factors

    Lin, Rulong; Stekoll, Michael (Science Publishing Group, 2013-06-30)
    Investigations were performed on variations of photosynthetic pigment in conchocelis of Alaskan Porphyra species, P. abbottae (Pa), P. pseudolanceolata (Pe), P. pseudolinearis (Pi) and P. torta (Pt), in response to environmental variables. Conchocelis were cultured under varying conditions of irradiance (0, 10, 40 and 160 µmol photons m-2s-1), nutrient concentration (0, f/4, f/2 and f) for up to 60 days (with temperature 11°C and salinity 30ppt). Chlorophyll a (Chl a ) content was measured by spectrophotometry. Results indicated that Chl content varied with different culture conditions and species. Photosynthetic pigment was significantly affected by irradiance, nutrient concentration and culture duration, including some interactions of major factors for different species. Light had the most obvious influence on pigment content. For all four species and culture conditions tested, the higher Chl a content (3.6-8.6 mg/g.dw) generally occurred at 0-10 µmol photons m 2 s 1than at higher irradiances (≥40 µmol photons m-2s-1 ) culture. For all culture conditions, Chl a content in conchocelis culture with no nutrients added was the lowest. Although there was some difference in Chl a content for cultures with f/2-f nutrient concentration, it was not statistically significant. ANOVA results showed that culture duration had influence on Chl a content of Pa, Pe and Pi species. However, pooled data analysis indicated there was no obvious difference in Chl content for four species of 10-60day culture. There were significant differences in photosynthetic pigment content for different species. Pa and Pi produced much higher pigment content than the other two species responding to different environmental conditions. Maximal Chl. a content (8.6 mg/g.dw) for Pa occurred at 0 µmol photons m-2s-1, f/2 nutrient concentration and 10 day culture duration. Pt contained the lowest pigment content for all culture conditions. Photosynthetic pigment remained relatively higher content under the complete darkness or the low irradiance continuously as long as 60 days for all tested species, which demonstrated the unique survival feature of Porphyra conchocelis. Variation patterns of pigment content, ecological significance and adaptation strategy to low or dark light conditions for microscopic conchocelis stage of Porphyra were discussed.
  • Coexistence despite recruitment inhibition of kelps by subtidal algal crusts

    Okamoto, Daniel K.; Stekoll, Michael; Eckert, Ginny L. (Inter-Research, 2013-11-20)
    In temperate subtidal reefs, kelp species often dominate light, while encrusting algae often dominate the substrate and are well adapted to low light conditions. Yet whether changes in algal crust cover impact recruitment dynamics of kelp species remains largely unexplored. To address this gap, we combined field surveys with laboratory and field experiments to investigate (1) the impact of algal crusts on kelp settlement and recruitment and (2) the potential effect such inhibition may have on density of subtidal kelps in a southeast Alaskan fjord. Experimental removal of algal crusts in the field resulted in dense kelp recruitment, whereas in plots where algal crusts dominated space, kelp recruitment was sparse. Kelp zoospores settled in the laboratory with no apparent selectivity for bare rock over crust surfaces, yet kelp sporophyte densities were reduced by 97 to 99% on non-coralline algal crust patches compared to bare rock, suggesting post-settlement recruitment inhibition. Despite such strong inhibition, we show that very low kelp recruit density, such as that observed in the algal crust dominated patches of our experiment, can yield high adult densities. Such observations are supported by positive correlations between kelp density and crust percent cover in field surveys of 1 m2 plots across 6 reefs, suggesting broad-scale coexistence. Thus, the strong ability of kelps to colonize bare substrata in this region appears to facilitate persistence of kelps despite strong dominance of space by certain algal crusts.
  • Effects of density and substrate type on recruitment and growth of Pyropia torta (Rhodophyta) gametophytes

    Conitz, Jan M.; Fagen, Robert; Stekoll, Michael (Walter de Gruyter GmbH, 2013-10-29)
    Does density affect recruitment and growth in the annual, blade phase of Pyropia sp., does self-thinning occur, and does substrate affect recruitment? These questions were investigated in laboratory-cultured Pyropia torta, a naturally occurring species in Alaska with mariculture potential. Three density levels were produced from conchospores. Measurements were made, initially at settlement and germination and, subsequently, at approximately 3-week intervals, in 12 randomly selected cultures from each density level. Settled spores, germlings, or growing blades were counted microscopically and standardized to unit area. Blade surface area was measured microscopically using image analysis software. Three density levels were still distinct at germination, but the high and medium levels were not significantly different. The germination rate of conchospores was highest at the medium density level, suggesting facilitation at moderate densities but inhibition at higher densities. Significant self-thinning occurred at each density level but differed among levels, while overall blade growth was about 10-fold greater at low density than at the other two levels. In a separate experiment, counts of attached spores per unit area on artificial substrate materials were greatest on materials with interstitial spaces large enough to trap spores until they become firmly attached.
  • Opportunities, challenges and future directions of open-water seaweed aquaculture in the United States

    Kim, JangKyun; Stekoll, Michael; Yarish, Charles (Taylor & Francis, 2019-09-11)
    Seaweed aquaculture is a relatively young industry in the United States compared to Asian countries. Early attempts at seaweed aquaculture in California, Washington State, New York and the Gulf of Maine in the 1980s and 1990s did not result in commercial production but provided important lessons. Since 2010, commercial cultivation of kelp (Saccharina latissima, Laminaria digitata, and Alaria esculenta) and other seaweeds (Palmaria palmata and Porphyra umbilicalis) began in the Gulf of Maine and Long Island Sound. Seaweed aquaculture is now a fast-growing maritime industry, especially in New England. If seaweed aquaculture is to maintain its momentum, it is important to (1) emphasise the environmental benefits; (2) domesticate a variety of local species; and (3) diversify seaweed products for food, animal feed, phycocolloids, cosmeceuticals, nutraceuticals, and ultimately biofuels if it becomes economically viable due to the cost of production. The exclusive economic zone (EEZ) of the United States offers opportunities for expansion of seaweed aquaculture in an area greater than the entire land mass of the United States and with limited user conflicts. This study reviews the past and current status of seaweed aquaculture in the United States and discusses potential opportunities and challenges of open-water seaweed aquaculture.
  • Oceanographic growth of seaweed data, morphometric data, and data from a Spotter Buoy

    Stekoll, Michael (Springer, 2024)
    On publication, data files will be available through ScholarWorks@UA (, an open data repository. The datasets generated during the current study are also available from the corresponding author on reasonable request.
  • Mariculture research of Macrocystis pyrifera and Saccharina latissima in Southeast Alaska

    Stekoll, Michael; Peeples, Tamsen; Raymond, Ann E. T. (Wiley, 2021-10)
    There has been increasing interest in Alaska regarding the commercial mariculture of kelp. Kelp farming can be an economic engine for coastal communities of Alaska. Other benefits include ecosystem services, including carbon sequestration and mitigation of eutrophication. In support of this interest, several kelp species have been examined for commercial potential. In the 1980s–1990s, experiments were performed on the giant kelp Macrocystis pyrifera. Female gametophytes were exposed to varying levels of chelated iron. Relatively low levels of chelated iron (1–5 μM) stimulated the onset of oogenesis. In contrast, higher iron concentrations inhibited egg production. Outplant experiments with Macrocystis in Sitka, AK showed growth in the winter and spring, slowing down to zero growth by the end of summer. Fertilizing outplants in August allowed plants to survive and grow during the ensuing winter. Mariculture experiments with Saccharina latissima carried out near Juneau, Alaska showed exponential growth for seeded lines set out from September to March. Optimal growth occurred for outplants in October–November, with growth rates of up to 5% per day. The best growth occurred when lines were 2–3 m below the surface. Growth rates declined in May–June corresponding to a decrease in inorganic nitrogen in the water. Slower growth also resulted in severe fouling.
  • Regenerative tourism and mental health: The clean wave foundation, Costa Rica

    Thornton, Michele; Bhatia, Marty; Silkaitis, Carin (Springer Nature Switzerland, 2024-06-01)
    Rising mental health needs combined with barriers in access to care has individuals seeking new approaches to accessing care and improving their overall sense of well-being. Intentional forms of tourism, particularly nature-based, and regenerative tourism may have a role to play as an opportunity to address this growing need in a way that traditional efforts to address mental health may be lacking. While studies have begun to document the physical health, mental health and perceptions of well-being impacts of nature-based, sustainable or ecotourism they are just beginning to explore this with regards to regenerative tourism. Regenerative tourism, is slightly more nuanced, and is described as “leaving the place behind better than before.” A hallmark of a sound regenerative tourism model, is that it emerges from within the community, and is often tied to a local community organization doing the ongoing work that spearheads the practice. This paper employs grounded theory to proposes a new model linking regenerative tourism to well-being and documents a qualitative study conducted in the Spring of 2023 with a regenerative based organization (The Clean Wave Foundation)—that connects individuals with beach and underwater clean-up events across Costa Rica. Key participants (n = 12) discuss their experiences, personal well-being and community impacts in a semi-structured interview format. Community organizations, economic development agencies, the tourism industry and scholars in marketing and public health will all find benefit in this work.
  • The need for embodied dramaturgy: The Laramie Project and Generation Z

    Silkaitis, Carin; Kriegler-Wenk, Zoe Rose (Athens Institute for Education and Research, 2023-07)
    20 years after the murder of Matthew Shepard, I introduced The Laramie Project to a group of undergraduate students. Observing cast members' first experience of the characters, a troubling lack of empathy to the complexity of this tragic story became apparent. Of primary concern was that decades of progress made towards LGBTQIA equality stripped this story of its relevance. Geographic and generational bias is natural and expected but ultimately requires a new dramaturgical approach. We offer reflections on the methodology developed to address this gap: an embodied dramaturgical approach to our pre-production work culminating in a full cast and crew research trip to Laramie, Wyoming. Through photos, video, soundscapes and observations, we illuminate the impacts of using a place-based, psycho-somatic sensory approach to dramaturgical research. This experience created physical and emotional transformation in the participants that can inform future dramaturgical work particularly for stories that are deeply unknown and unfamiliar to the cast and crew. Together, we found that stories like “The Laramie Project” continue to be relevant. Although progress has been great, the threat of anti-LGBTQIA violence is still very real for many people. Employing an embodied approach can enhance storytelling and empower further progress with the benefit of today’s experience.
  • Estimating production cost for large-scale seaweed farms

    Kite-Powell, Hauke L.; Ask, Erick; Augyte, Simona; Bailey, David; Decker, Julie; Goudey, Clifford A.; Grebe, Gretchen; Li, Yoaguang; Lindell, Scott; Manganelli, Domenic; et al. (Taylor & Francis, 2022-07)
    Seaweed farming has the potential to produce feedstocks for many applications, including food, feeds, fertilizers, biostimulants, and biofuels. Seaweeds have advantages over land-based biomass in that they require no freshwater inputs and no allocation of arable land. To date, seaweed farming has not been practiced at scales relevant to meaningful biofuel production. Here we describe a techno-economic model of large-scale seaweed farms and its application to the cultivation of the cool temperate species Saccharina latissima (sugar kelp) and the tropical seaweed Eucheumatopsis isiformis. At farm scales of 1000 ha or more, our model suggests that farm gate production costs in waters up to 200 km from the onshore support base are likely to range between $200 and $300 per dry tonne. The model also suggests that production costs below $100 per dry tonne may be achievable in some settings, which would make these seaweeds economically competitive with land-based biofuel feedstocks. While encouraging, these model results and some assumptions on which they are based require further field validation.
  • Trophic stability and change across a sea ice cover gradient on the western Antarctic Peninsula

    Galloway, A. W. E.; Schram, Julie; Lowe, A. T.; Whippo, R.; Heiser, S.; Iken, K.; McClintock, J. B.; Klein, A. G.; Amsler, M. O.; Amsler, C. D. (Inter-Research, 2024-05-02)
    The western Antarctic Peninsula (AP) is experiencing significant changes to sea ice cover, altering the macroalgal cover and potentially affecting the foundation of benthic food webs. We used fatty acid signatures as dietary and physiological trophic biomarkers to test the hypothesis that a gradient of 36-88% mean annual ice cover would affect the trophic ecology of fleshy macroalgae and diverse benthic invertebrate consumers along the western AP. We used SCUBA to collect organisms from benthic rocky nearshore habitats, 5-35 m depth, at 15 study sites during April-May of 2019. There were no consistent ecosystem-scale differences in the nutritionally important polyunsaturated fatty acids or other univariate fatty acid summary categories in either the seaweeds or invertebrates across the ice gradient, but we did find site-level differences in the multivariate fatty acid signatures of all seaweeds and invertebrates. Ice cover was a significant driver of the fatty acid signatures of 5 invertebrates, including 3 sessile (an anemone, a sponge, and a tunicate) and 2 mobile consumers (a sea star and a sea urchin). The multivariate fatty acid signatures of 2 other sea stars and a limpet were not affected by the ice gradient. These results indicate that the trophic ecology and resource assimilation of sessile consumers that are more connected to the macroalgal-derived food web will be more sensitive than mobile consumers to impending changes to annual ice and macroalgal cover along the western AP.
  • Fatty acid profiles and stable isotope composition of Antarctic macroalgae: a baseline for a combined biomarker approach in food web studies

    Whippo, Ross; Iken, Katrin; Amsler, Charles D.; Lowe, Alexander T.; Schram, Julie; Klein, Andrew G.; Heiser, Sabrina; Amsler, Margaret O.; McClintock, James B.; Galloway, Aaron W. E. (Springer Nature, 2024-03-26)
    The Western Antarctic Peninsula supports a diverse assemblage of > 100 described macroalgal species that contribute to the base of coastal food webs, but their contribution to local nearshore food webs is still uncertain across larger spatial scales. The analysis of biomarkers, specifically fatty acids and stable isotopes, offers a tool to clarify the trophic role of Antarctic macroalgae. The aim of this study was to describe the fatty acid profiles and stable isotope values of 31 algal species from three divisions (Chlorophyta—1, Ochrophyta—8, Rhodophyta—22) collected at the same sites for both biomarkers. Of these, 13 species had no previously published fatty acid profiles. Most species were rich in polyunsaturated fatty acids (PUFAs), suggesting they are highly nutritious and could be a resource of essential fatty acids for consumers. This was specifically noticeable in the overall low PUFA ratio (∑ω6/∑ω3 ratio), with low ratios being an indicator of high nutritional quality for consumers. Fatty acid profiles of macroalgae grouped strongly by phylogeny (at the levels of division, order, and family), while stable isotope groupings were more driven by the physiological properties of the species. Specifically, some closely related red algal species exhibited very different stable isotope values based on their carbon concentrating mechanisms, with highly 13C-depleted values in several Rhodophyta species. The fact that the two biomarker approaches created different groupings of Antarctic macroalgae collected at the same locations emphasizes that their combined application can be a powerful tool in Antarctic coastal food web studies.
  • Snow avalanches are a primary climate-linked driver of mountain ungulate populations

    White, Kevin S.; Hood, Eran; Wolken, Gabriel J.; Peitzsch, Erich H.; Bühler, Yves; Jones, Katreen Wikstrom; Darimont, Chris T. (Springer Nature, 2024-04-29)
    Snow is a major, climate-sensitive feature of the Earth’s surface and catalyst of fundamentally important ecosystem processes. Understanding how snow influences sentinel species in rapidly changing mountain ecosystems is particularly critical. Whereas effects of snow on food availability, energy expenditure, and predation are well documented, we report how avalanches exert major impacts on an ecologically significant mountain ungulate - the coastal Alaskan mountain goat (Oreamnos americanus). Using long-term GPS data and field observations across four populations (421 individuals over 17 years), we show that avalanches caused 23−65% of all mortality, depending on area. Deaths varied seasonally and were directly linked to spatial movement patterns and avalanche terrain use. Population-level avalanche mortality, 61% of which comprised reproductively important prime-aged individuals, averaged 8% annually and exceeded 22% when avalanche conditions were severe. Our findings reveal a widespread but previously undescribed pathway by which snow can elicit major population-level impacts and shape demographic characteristics of slow-growing populations of mountain-adapted animals.
  • Perceived challenges to tribally led shellfish toxin testing in Southeast Alaska: Findings from key informant interviews

    Roland, Hugh B.; Kohlhoff, Jacob; Lanphier, Kari; Hoysala, Sneha; Kennedy, Esther G.; Harley, John R.; Whitehead, Christopher; Gribble, Matthew O. (John Wiley & Sons, Inc., 2024-03-07)
    Shellfish harvesting is central to coastal Alaska Native ways of life, and tribes in Southeast Alaska are committed to preserving sustainable and safe access to subsistence foods. However, consumption of non-commercially harvested shellfish puts Alaska Native communities at elevated risk of exposure to shellfish toxins. To address a lack of state or federal toxin testing for subsistence and recreational harvesting, tribes across Southeast Alaska have formed their own toxin testing and ocean monitoring program. In this study, we interviewed environmental managers responsible for tribes' testing and others with shellfish toxin expertise to report on perceptions of barriers to tribally led testing in Southeast Alaska. Tribal staff identified 40 prospective key informants to interview, including all environmental managers responsible for shellfish toxin testing at subsistence sites in Southeast Alaska. All 40 individuals were invited to participate in an interview and 27 individuals were interviewed. The most frequently discussed barriers to shellfish toxin testing in Southeast Alaska relate to logistical and staffing difficulties associated with communities' remote locations, inconsistent and inadequate funding and funding structures that increase staff burdens, risk communication challenges related to conveying exposure risks while supporting subsistence harvesting, and implications of climate change-related shifts in toxin exposures for risk perception and risk communication. Participants stressed the social origins of perceived barriers. Disinvestment may create and sustain barriers and be most severely felt in Native communities and remote places. Climate change impacts may interact with social and cultural factors to further complicate risk management.
  • Glaciers, snow, and rain: Water source influences invertebrate community structure and secondary production across a hydrologically diverse subarctic landscape

    Dunkle, Matthew; Bellmore, J. Ryan; Fellman, Jason; Caudill, Christopher C. (John Wiley & Sons, Inc., 2024-02)
    The melting cryosphere adds heterogeneity to the abiotic and biotic characteristics of many high latitude and montane rivers. However, climate change threatens the cryosphere's persistence in many regions. While existing research has explored the impacts of cryospheric loss on the diversity and structure of freshwater communities, implications for functional traits of communities, such as production of aquatic invertebrates, remain unresolved. Here, we quantified aquatic invertebrate community structure and secondary production in southeast Alaska (USA) streams that represent a meltwater to non-meltwater gradient, including streams fed primarily by: (1) glacier-melt, (2) snowmelt, (3) rainfall, and (4) a combination of these sources. We found alpha diversity was highest in the snow-fed stream and lowest in the glacier-fed stream. Annual secondary production was also lowest in the glacier-fed stream (0.56 g ash-free dry mass m−2), but 2–5 times higher in the other stream types primarily due to greater production of shared taxa that were found in all streams. However, despite low invertebrate diversity and productivity, the glacier-fed stream hosted distinct species assemblages associated with unique cycles of stream flow, water temperature, turbidity, and nutrient concentrations, which contributed to higher beta diversity between streams. Our findings suggest that the loss of glacier-melt contributions to rivers may result in increased freshwater invertebrate production but reduced beta diversity, which could have implications for community stability and the capacity of landscapes to support higher-level consumers, including fishes.
  • Assessing the dynamics of common dolphin (Delphinus delphis) mother-calf pairs along the south coast of Portugal using unmanned aerial vehicles

    Castro, Joana; Cid, André; Quirin, Alicia; Matos, Fábio L.; Rosa, Rui; Pearson, Heidi (John Wiley & Sons, Inc., 2024-02-13)
    Maternal grouping dynamics involve trade-offs between: (1) infant protection from predation (predation hypothesis), (2) infant protection from male harassment (infant safety hypothesis), and (3) reducing scramble competition for prey resources (foraging-type scramble competition hypothesis). Using unmanned aerial vehicles, we assessed grouping dynamics in common dolphin (Delphinus delphis) groups containing mother-calf pairs to address these hypotheses. We analyzed social aspects and structural group elements using generalized additive mixed models and modeled group formation using multinomial generalized estimating equations. Calf proportion was higher in very compact groups and in groups of 10–20 individuals but decreased in larger groups. The frequency of socio-sexual behaviors increased in larger groups and decreased in groups with higher calf proportion. Calf distance to its nearest neighbor decreased with increasing group size and cohesion. With a higher proportion of calves, scatter (versus parallel) formation was less frequent. A calf's nearest neighbor was most often (55.4%) a nonmother. Calves showed a preference for being in the front center of the group. These results offer strong support for the predation and infant safety hypotheses and partial support for the foraging-type scramble competition hypothesis. This work provides insight into the adaptive function of maternal strategies in a small delphinid.
  • Dusky dolphin (Lagenorhynchus obscurus) habitat use in a mussel farming region and changes over time

    Piwetz, Sarah; Pearson, Heidi; Honkus, Krysta A.; Würsig, Bernd (Taylor & Francis, 2024-04-01)
    Information on marine mammal habitat use in coastal areas can provide a better understanding of anthropogenic effects on species. Admiralty Bay, New Zealand has extensive near-shore mussel farms and is an important dusky dolphin (Lagenorhynchus obscurus) foraging habitat. Prior dusky dolphin research indicated a declining trend in regional abundance from the late 1990s to mid-2000s. We describe dusky dolphin behaviour, habitat patch use and movement patterns in Admiralty Bay in 2011–2012 and compare findings to previous research to capture long-term trends. Sampling methods included small-boat group follows and photo-identification and shore-based theodolite tracking. Dolphin encounter rate, mean group size, and individual resighting rate showed a negative trend from previous years. Coordinated prey ball herding, a foraging technique documented in previous years, was rarely observed during this study. Dolphins were more likely to forage near farms (excluding specialised prey herding), though they seldom entered farms. Near shore, swimming speed was slower, reorientation rate was higher, and linearity was lower in the presence of farms than in their absence. This research builds upon prior studies, suggesting a continued decline in dusky dolphin presence, and highlights differences in habitat patch use in a human-altered ecosystem.
  • Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska

    Atkinson, S.; Melica, V.; Teerlink, S.; Mashburn, K.; Moran, J.; Pearson, Heidi (Elsevier, 2023)
    Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p < 0.05). Progesterone concentrations in adult male whales (0.3 ± 0.2 ng/g) were not significantly different from lactating or resting female whales. Blubber testosterone concentrations in adult male humpback whales ranged from 0.05 to 1.1 ng/g, and mean concentrations were approximately double those of female whales in any reproductive state. Pregnancy was detected in 5 of 11 and 4 of 9 adult females in 2020 and 2021 respectively, yielding summer season pregnancy rates for sexually mature females at 0.45, and 0.44, respectively. Calving rates were 0.36 and 0.22 in 2020 and 2021, respectively, and the annual growth rate for this subpopulation was calculated at 2.6 % per annum. One female had successful pregnancies for four consecutive years. These results demonstrate the synergistic value of combining immunoreactive assays and long-term sighting histories to further knowledge of reproductive physiology in individual humpback whales, which can be expanded to assessing the health of a population or ecosystem.
  • Macronutrient composition of sea otter diet with respect to recolonization, life history, and season in southern Southeast Alaska

    LaRoche, Nicole; King, Sydney; Fergusson, Emily; Eckert, Ginny; Pearson, Heidi (John Wiley & Sons, Inc., 2023-05-02)
    The sea otter (Enhydra lutris) population of Southeast Alaska has been growing at a higher rate than other regions along the Pacific coast. While good for the recovery of this endangered species, rapid population growth of this apex predator can create a human-wildlife conflict, negatively impacting commercial and subsistence fishing. Previous foraging studies throughout the sea otter range have shown they will reduce invertebrate prey biomass when recolonizing an area. The goal of this study was to examine and quantify the energy content of sea otter diets through direct foraging observations and prey collection. Our study area, Prince of Wales Island in southern Southeast Alaska, exhibits a gradient of sea otter recolonization, thus providing a natural experiment to test diet change in regions with different recolonization histories. Sea otter prey items were collected in three seasons (spring, summer, and winter) to measure caloric value and lipid and protein content. We observed 3523 sea otter dives during the spring and summer. A majority of the sea otter diet consisted of clams. Sea otters in newly recolonized areas had lower diet diversity, higher energetic intake rates (EIR, kcal/min), and prey had higher energy content (kcal/g). Females with pups had the highest diet diversity and the lowest EIR. Sea otter EIR were higher in the fall and winter vs. spring and summer. Sea cucumber energy and lipid content appeared to correspond with times when sea otters consumed the highest proportion of sea cucumbers. These caloric variations are an important component of understanding ecosystem-level effects sea otters have in the nearshore environment.

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