Glacier Bay National Research Articles

Estimating occupancy and abundance using aerial images with imperfect detection

Abstract Species distribution and abundance are critical population characteristics for efficient management, conservation, and ecological insight. Point process models are a powerful tool for modelling distribution and abundance, and can incorporate many data types, including count data, presence‐absence data, and presence‐only data. Aerial photographic images are a natural tool for collecting data to fit point process models, but aerial images do not always capture all animals that are present at a site. Methods for estimating detection probability for aerial surveys usually include collecting auxiliary data to estimate the proportion of time animals are available to be detected. We developed an approach for fitting point process models using an N‐mixture model framework to estimate detection probability for aerial occupancy and abundance surveys. Our method uses multiple aerial images taken of animals at the same spatial location to provide temporal replication of sample sites. The intersection of the images provide multiple counts of individuals at different times. We examined this approach using both simulated and real data of sea otters (Enhydra lutris kenyoni) in Glacier Bay National Park, southeastern Alaska. Using our proposed methods, we estimated detection probability of sea otters to be 0.76, the same as visual aerial surveys that have been used in the past. Further, simulations demonstrated that our approach is a promising tool for estimating occupancy, abundance, and detection probability from aerial photographic surveys. Our methods can be readily extended to data collected using unmanned aerial vehicles, as technology and regulations permit. The generality of our methods for other aerial surveys depends on how well surveys can be designed to meet the assumptions of N‐mixture models.

Genetic assessment of the effects of streamscape succession on coho salmon Oncorhynchus kisutch colonization in recently deglaciated streams.

Measures of genetic diversity within and among populations and historical geomorphological data on stream landscapes were used in model simulations based on approximate Bayesian computation (ABC) to examine hypotheses of the relative importance of stream features (geomorphology and age) associated with colonization events and gene flow for coho salmon Oncorhynchus kisutch breeding in recently deglaciated streams (50-240 years b.p.) in Glacier Bay National Park (GBNP), Alaska. Population estimates of genetic diversity including heterozygosity and allelic richness declined significantly and monotonically from the oldest and largest to youngest and smallest GBNP streams. Interpopulation variance in allele frequency increased with increasing distance between streams (r = 0·435, P < 0·01) and was inversely related to stream age (r = -0·281, P < 0·01). The most supported model of colonization involved ongoing or recent (<10 generations before sampling) colonization originating from large populations outside Glacier Bay proper into all other GBNP streams sampled. Results here show that sustained gene flow from large source populations is important to recently established O. kisutch metapopulations. Studies that document how genetic and demographic characteristics of newly founded populations vary associated with successional changes in stream habitat are of particular importance to and have significant implications for, restoration of declining or repatriation of extirpated populations in other regions of the species' native range.

Disturbance of a rare seabird by ship-based tourism in a marine protected area.

Managers of marine protected areas (MPAs) must often seek ways to allow for visitation while minimizing impacts to the resources they are intended to protect. Using shipboard observers, we quantified the “zone of disturbance” for Kittlitz’s and marbled murrelets (Brachyramphus brevirostris and B. marmoratus) exposed to large cruise ships traveling through Glacier Bay National Park, one of the largest MPAs in North America. In the upper reaches of Glacier Bay, where Kittlitz’s murrelets predominated, binary logistic regression models predicted that 61% of all murrelets within 850 m perpendicular distance of a cruise ship were disturbed (defined as flushing or diving), whereas in the lower reaches, where marbled murrelets predominated, this percentage increased to 72%. Using survival analysis, murrelets in both reaches were found to react at greater distances when ships approached indirectly, presumably because of the ship’s larger profile, suggesting murrelets responded to visual rather than audio cues. No management-relevant covariates (e.g., ship velocity, route distance from shore) were found to be important predictors of disturbance, as distance from ship to murrelet accounted for > 90% of the explained variation in murrelet response. Utilizing previously published murrelet density estimates from Glacier Bay, and applying an average empirical disturbance probability (68%) out to 850 m from a cruise ship’s typical route, we estimated that a minimum of 9.8–19.6% of all murrelets in Glacier Bay are disturbed per ship entry. Whether these disturbance levels are inconsistent with Park management objectives, which include conserving wildlife as well as providing opportunities for visitation, depends in large part on whether disturbance events caused by cruise ships have impacts on murrelet fitness, which remains uncertain.

Interannual site fidelity of Pacific halibut: potential utility of protected areas for management of a migratory demersal fish

Abstract Pacific halibut is a large-bodied demersal fish species known to undertake large-scale winter spawning migrations. We characterized annual movement patterns of Pacific halibut relative to a Marine Protected Area (MPA) in Glacier Bay National Park, Alaska using electronic tags. In the summer of 2013, we deployed 25 Pop-up Satellite Archival Tags (PSATs) on halibut to determine seasonal movement patterns, where residency within the MPA was inferred by comparing PSAT depth and temperature records to stationary archival tag data and oceanographic survey data. To characterize within-summer movement patterns, 15 halibut tagged with PSATs were double-tagged with acoustic transmitters and actively tracked during the summers of 2013 and 2014. Home range behaviour and interannual site fidelity at spatial scales &amp;lt;5 km were observed for the majority of tagged fish. A small proportion (6/21 fish with PSAT data) departed the MPA on winter migrations during December 2013. A majority (4/6) of migratory fish returned to the MPA after an average of 57 d (s.d. 22 d) spent outside of the MPA. Migration timing generally coincided with existing winter commercial fishery closures. The annual movement patterns of tagged halibut relative to MPA boundaries and winter commercial fisheries closures suggest that the Glacier Bay MPA could serve as a year-round refuge from commercial harvest for both residential and migratory halibut. If halibut behaviour is similar in other areas, protected areas may provide some utility for management despite the migratory nature of halibut.

Source levels and call parameters of harbor seal breeding vocalizations near a terrestrial haulout site in Glacier Bay National Park and Preserve

Source levels of harbor seal breeding vocalizations were estimated using a three-element planar hydrophone array near the Beardslee Islands in Glacier Bay National Park and Preserve, Alaska. The average source level for these calls was 144 dBRMS re 1 μPa at 1 m in the 40-500 Hz frequency band. Source level estimates ranged from 129 to 149 dBRMS re 1 μPa. Four call parameters, including minimum frequency, peak frequency, total duration, and pulse duration, were also measured. These measurements indicated that breeding vocalizations of harbor seals near the Beardslee Islands of Glacier Bay National Park are similar in duration (average total duration: 4.8 s, average pulse duration: 3.0 s) to previously reported values from other populations, but are 170-220 Hz lower in average minimum frequency (78 Hz).

Effects of marine vessel management on the underwater acoustic environment of Glacier Bay National Park, AK

To protect the underwater acoustic environment and the marine mammals that depend upon it, Glacier Bay National Park implements marine vessel quotas, speed regulations, and routing restrictions in biologically important areas. Here, we characterize the underwater acoustic environment to quantify changes in conditions related to vessel management actions. Analysis of hourly 30-second acoustic samples obtained from a seafloor hydrophone included manual (aural and visual) identification of physical, biological, and human-made acoustic sources and measuring received sound pressure levels. A total of 10,659 30-second acoustic samples collected in 2000, 2001, 2007 and 2008 were analyzed. By quantifying the sources, occurrence, and characteristics of underwater sound we gained a new understanding of how the underwater acoustic environment relates to vessel management. For example, the occurrence of noise from large marine vessels (e.g. cruise ships) decreased despite an increase in the vessel quotas and use-days, likely due to changes in the timing of cruise ship entries. Our work documented the occurrence of biologically important humpback whale and harbor seal vocalizations; the frequency of occurrence of these vocalizations gives an indication of Glacier Bay's importance for these species and seasonality of calls documents the times of year at which a pristine acoustic environment would most benefit each species. These first descriptions of acoustic conditions in a protected coastal habitat indicate that both regulations and vessel behavior independent of regulations have discernible effects on the acoustic environment. Quantitatively describing these changes is a crucial first step toward protection of this important underwater habitat.

Keeping the bay in Glacier Bay National Park: Introducing glacier science to the United States Supreme Court

ABSTRACT In 2000, seventy-five years after the founding of Glacier Bay National Monument, the United States Supreme Court authorized the State of Alaska to begin legal proceedings related to the ownership of ‘certain marine submerged lands in southeast Alaska’ including the submerged lands contained within what is now Glacier Bay National Park. This narrative presents a summary of how glacier science (glacial geology and glaciology) became an integral part of the argument prepared and presented by the United States Government in response to the State of Alaska's Complaint.

Natural history, population dynamics, and habitat use of humpback whales over 30 years on an Alaska feeding ground

AbstractThe rigorous program of monitoring humpback whales (Megaptera novaeangliae), implemented by Glacier Bay National Park and Preserve in 1985, augmented by additional data collected in southeastern Alaska since 1968, constitutes one of the longest studies of living whales in the world. This monitoring program, now a National Park Service (NPS) Inventory and Monitoring Program Vital Sign, employed consistent methods for summer surveys from 1985 to 2014 to document the number of whales and gather longitudinal records on individuals in Glacier Bay and Icy Strait. Survey effort averaged 355.4 h/yr (SD = 45.8), resulting in 9485 encounters with 662 individual whales, including 276 calves. The population increased at a rate of 5.1%/yr, from 41 individuals in 1985 to 239 individuals in 2013, primarily due to long‐term site fidelity and local recruitment. We documented sighting histories of &gt;30 yr in southeastern Alaska, for 54 whales, including one 45‐yr sighting history. Almost half of the whales first identified as calves returned in subsequent years, at a mean age of 3.2 yr (SE = 0.28, range = 1–17 yr). Over 75% of females had their first calf by age 13. The maximum female reproductive span was 32 yr, and the maximum number of calves was 11. We estimated mean effective calving rate with a simple ratio and used logistic regression to estimate calving probability. Both methods resulted in similar maximal estimates that were somewhat lower than previously published values for this species: 0.324 (95% CL: 0.28–0.36) calves·female−1·yr−1 vs. calving probability of 0.319 (95% CL: 0.29–0.35). Minimal estimates, in which the first calf of each known‐aged female was omitted, were 0.302 (95% CL: 0.27–0.34) calves·mature female−1·yr−1 vs. calving probability of 0.305 (95% CL: 0.27–0.34) calves·mature female−1·yr−1. This monitoring program has guided Park management actions and documented this once critically endangered population's trajectory toward recovery, often through collaboration with other agencies and organizations, fostering the continued protection and understanding of this distinctive species. Our findings highlight the value of marine protected areas for migratory species with strong seasonal site fidelity and the role of long‐term monitoring in interpreting population‐level responses to changing marine ecosystems.

Quantification and Analysis of Icebergs in a Tidewater Glacier Fjord Using an Object-Based Approach.

Tidewater glaciers are glaciers that terminate in, and calve icebergs into, the ocean. In addition to the influence that tidewater glaciers have on physical and chemical oceanography, floating icebergs serve as habitat for marine animals such as harbor seals (Phoca vitulina richardii). The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords. We present a case study to describe a novel method that uses object-based image analysis (OBIA) to classify floating glacier ice in a tidewater glacier fjord from high-resolution aerial digital imagery. Our objectives were to (i) develop workflows and rule sets to classify high spatial resolution airborne imagery of floating glacier ice; (ii) quantify the amount and fine-scale characteristics of floating glacier ice; (iii) and develop processes for automating the object-based analysis of floating glacier ice for large number of images from a representative survey day during June 2007 in Johns Hopkins Inlet (JHI), a tidewater glacier fjord in Glacier Bay National Park, southeastern Alaska. On 18 June 2007, JHI was comprised of brash ice ( = 45.2%, SD = 41.5%), water ( = 52.7%, SD = 42.3%), and icebergs ( = 2.1%, SD = 1.4%). Average iceberg size per scene was 5.7 m2 (SD = 2.6 m2). We estimate the total area (± uncertainty) of iceberg habitat in the fjord to be 455,400 ± 123,000 m2. The method works well for classifying icebergs across scenes (classification accuracy of 75.6%); the largest classification errors occur in areas with densely-packed ice, low contrast between neighboring ice cover, or dark or sediment-covered ice, where icebergs may be misclassified as brash ice about 20% of the time. OBIA is a powerful image classification tool, and the method we present could be adapted and applied to other ice habitats, such as sea ice, to assess changes in ice characteristics and availability.

Source levels and calling rates for humpback whale (Megaptera novaeangliae) non-song vocalizations in Glacier Bay Alaska

Marine resource managers in Glacier Bay National Park, Alaska, have been tasked with assessing the impact of vessel noise on marine mammal species. Humpback whales (Megaptera novaeangliae) are a highly vocal baleen whale that forage between spring and fall in Park waters. While calling rates and source levels for this species have been described on breeding grounds and migratory corridors, these fundamental acoustic parameters have not been thoroughly described on foraging grounds, and have never been empirically measured in the North Pacific. Using a three-element hydrophone array deployed in the Beardslee Island complex of Glacier Bay during the 2015 summer foraging season humpback whale “whup” and “growl” calls were localized and source levels were calculated. Array recordings were paired with shore based abundance estimates from the same period and calling rates (calls per whale per hour) were estimated. Known calling rates and source levels are essential for developing detection algorithms, masking metrics, and determining communication space on this historically important foraging ground.

Source levels of harbor seal underwater reproductive advertisement displays

Harbor seals (Phoca vitulina), along with the majority of other phocid species, mate underwater. During the breeding season, male harbor seals set up underwater territories and use acoustic cues, known as roars, to defend these areas against intruder males and possibly to attract females. Vocalizations are low in frequency, predominately around 60-100 Hz, with some broadband components reaching up to 5 kHz, and range from 4-10 seconds in duration. Previously, source levels of vocalizations have only been estimated. Here we present a method for measuring vocalizations to estimate source levels of harbor seal roars. We used a three-element hydrophone array in Glacier Bay National Park to record harbor seal vocalizations during the breeding season (June—July 2015). Using the array, we localized individual vocalizing animals and calculated source levels of calls in the 40-500 Hz range. Knowledge of source levels for vocalizations of harbor seals is important for understanding how anthropogenic forces, such as noise from vessels, may impact the acoustic behavior and communication range of these animals.

Using bioacoustics to examine shifts in songbird phenology.

Monitoring patterns in biodiversity and phenology have become increasingly important given accelerating levels of anthropogenic change. Long‐term monitoring programs have reported earlier occurrence of spring activity, reflecting species response to climate change. Although tracking shifts in spring migration represents a valuable approach to monitoring community‐level consequences of climate change, robust long‐term observations are challenging and costly. Audio recordings and metrics of bioacoustic activity could provide an effective method for monitoring changes in songbird activity and broader biotic interactions. We used 3 years of spring and fall recordings at six sites in Glacier Bay National Park, Alaska, an area experiencing rapid warming and glacial retreat, to examine the utility of bioacoustics to detect changes in songbird phenology. We calculated the Acoustic Complexity Index (ACI), an algorithm representing an index of bird community complexity. Abrupt changes in ACI values from winter to spring corresponded to spring transition, suggesting that ACI may be an effective, albeit coarse metric to detect the arrival of migrating songbirds. The first peak in ACI shifted from April 16 to April 11 from 2012 to 2014. Changes in ACI were less abrupt in the fall due to weather events, suggesting spring recordings are better suited to indicate phenology. To ensure changes in ACI values were detecting real changes in songbird activity, we explored the relationship between ACI and song of three species: varied thrush (Ixoreus naevius), Pacific wren (Troglodytes pacificus), and ruby‐crowned kinglet (Regulus calendula). ACI was positively related to counts of all species, but most markedly with song of the varied thrush, the most common species in our recordings and a known indicator of forest ecosystem health. We conclude that acoustic recordings paired with bioacoustic indices may be a useful method of monitoring shifts in songbird communities due to climate change and other sources of anthropogenic disturbance.

Tree Ring—Dated Glacial History for the First Millennium c.e., Casement Glacier and Adams Inlet, Glacier Bay, Alaska, U.S.A.

ABSTRACTCalendar dating of tree-ring series from 16 logs sampled near the margin of Casement Glacier combined with tree-ring dates on 36 detrital logs from Adams Inlet, Glacier Bay National Park and Preserve, Alaska, show killing of trees by ice and lake sediments from the mid-sixth through mid-seventh centuries c.e. The dates from the land-terminating Casement Glacier show ice advance into a forest between 560 and 570 c.e. within a few kilometers of the 2011 retreating margin. Advance of the tidewater glacier in Muir Inlet blocked off Adams Inlet forming Lake Adams between 540 and 640 c.e. This glacier and lake history for Glacier Bay is consistent with other land-terminating ice expansions across the Gulf of Alaska that similarly show advance centered on 600 c.e., as well as other proxy records from lakes all suggesting cooling during this interval. The cooling closely follows a series of eruptions in the mid to late sixth century, which may have contributed to the cooling. Radiocarbon ages in Adams Inlet suggest that Lake Adams persisted through 880 cal. yr c.e. and drained by 1170 cal. yr c.e. Ice retreat and this lake drainage are broadly coincident with Medieval warming recognized along the Gulf of Alaska in dendroclimatic reconstructions. Shortly after this retreat, Little Ice Age readvance occurred with Casement Glacier coalescing with glaciers in Adams Inlet and the West Arm, subsequently filling all of Glacier Bay to its Holocene maximum by 1750 c.e.

On the Limits to Manage Air-Quality in Glacier Bay

In Glacier Bay National Park, about 95% of the visitors come on board of cruise ships. The National Park Service has the mandate to manage park resources like air quality and visibility, while ensuring visitation. To understand the impact of cruise-ship emissions on the overall concentrations in Glacier Bay, emission-source contribution ratios (ESCR) and the interaction of pollutant from local and/or distant sources were determined using results from four WRF/Chem simulations of the 2008 tourist season (May 15 to September 15). These simulations only differed by the emissions considered: Biogenic emissions only (CLN), biogenic plus activity-based cruise-ship emissions (REF), biogenic plus all anthropogenic emissions except cruise-ship emissions (RETRO), and all aforementioned emissions (ALL). In general, ESCRs differed among pollutants. Interaction between pollutants from cruise-ship emissions and species from other sources including those advected into the bay decreased towards the top of the atmospheric boundary layer. Pollutants from different sources interacted strongest (lowest) in the west arm of the fjord where ships berthed for glacier viewing (in areas of the bay without cruise-ship travel). Pollutant interaction both enhanced/reduced NO2 concentrations by 10% (4 - 8 ppt absolute). Except for ozone, cruise-ship emissions on average governed air quality in the bay. On days with cruise-ship visits, they contributed between 60% and 80% of the bay-wide daily mean SO2 and NO2 concentrations below 1 km height. On days without visits, cruise-ship contributions still reached 40% due to previous visits. Highest cruise-ship ESCRs occurred during stagnant weather conditions. Despite the fact that all coarse particulate matter was due to anthropogenic sources, worst visibility conditions were due to meteorology. The results suggest limits as well as windows for managing air quality and visibility in Glacier Bay.

Conservation in a social-ecological system experiencing climate-induced tree mortality

We present a social-ecological framework to provide insight into climate adaptation strategies and diverse perspectives on interventions in protected areas for species experiencing climate-induced impacts. To develop this framework, we examined the current ecological condition of a culturally and commercially valuable species, considered the predicted future effects of climate change on that species in a protected area, and assessed the perspectives held by forest users and managers on future adaptive practices. We mapped the distribution of yellow-cedar (Callitropsis nootkatensis) and examined its health status in Glacier Bay National Park and Preserve by comparing forest structure, tree stress-indicators, and associated thermal regimes between forests inside the park and forests at the current latitudinal limit of the species dieback. Yellow-cedar trees inside the park were healthy and relatively unstressed compared to trees outside the park that exhibited reduced crown fullness and increased foliar damage. Considering risk factors for mortality under future climate scenarios, our vulnerability model indicated future expected dieback occurring within park boundaries. Interviews with forest users and managers revealed strong support for increasing monitoring to inform interventions outside protected areas, improving management collaboration across land designations, and using a portfolio of interventions on actively managed lands. Study participants who perceived humans as separate from nature were more opposed to interventions in protected areas. Linking social and ecological analyses, our study provides an interdisciplinary approach to identify system-specific metrics (e.g., stress indicators) that can better connect monitoring with management, and adaptation strategies for species impacted by climate change.

Impacts of Cruise-Ship Entry Quotas on Visibility and Air Quality in Glacier Bay

Managers at Glacier Bay National Park must annually determine the allowable number of cruise-ship entries into the park. This decision considers how differences in visitor volume may affect park resources. This study quantified the impacts to air quality and visibility under different ship quotas using simulations with the Weather Research and Forecasting model inline coupled with chemistry. Results of the simulation assuming two entries per day for May 15 to September 15, 2008 (QTA; 248 ship entries representing a 35% increase) were compared to those of the 2008 cruise-ship activity (REF; 184) during that timeframe. A simulation without anthropogenic emissions (CLN) served to assess the overall impacts of cruise-ship emissions on visibility and air quality in Glacier Bay. Compared to REF, the increased entry quotas shifted chemical regimes and aerosol composition, depending upon thermodynamical conditions, and ambient concentrations. On days with notable regime shifts, sulfur-dioxide concentrations deceased while ammonium-sulfate aerosol concentrations increased. The increased quotas also altered the fine-to-coarse aerosol ratios in both directions despite constant ratio of fine-to-coarse aerosol emissions. In Glacier Bay, the days with worst visibility coincided with high relative humidity, although this relationship varied by scenario. On the 20% worst days, mean visibility was slightly better in CLN (mean haze index over Glacier Bay waters = 2.9 dv) than in REF ( = 3.1 dv). While increased emissions in QTA reduced mean visibility by 0.1 dv, the 10th, 50th and 90th percentile of haze indices remained identical to those in REF. Best (worst) visibility occurred on the same days in REF and QTA due to emission impacts, but on different days than in CLN because relative humidity solely governed visibility in CLN. While calm wind played no role for visibility in CLN, wind speed gained similar importance for visibility as relative humidity in REF and QTA. Overall, increasing ship quotas would only marginally affect air quality and visibility as compared to REF, although even small changes in these parameters need careful consideration in the context of conserving the values of Glacier Bay.

Vegetation succession in deglaciated landscapes: implications for sediment and landscape stability

AbstractLandscapes exposed by glacial retreat provide an ideal natural laboratory to study the processes involved in transforming a highly disturbed, glacially influenced landscape to a stable, diverse ecosystem which supports numerous species and communities. Large‐scale vegetation development and changes in sediment availability, used as a proxy for paraglacial adjustment following rapid deglaciation, were assessed using information from remote sensing. Delineation of broad successional vegetation cover types was undertaken using Landsat satellite imagery (covering a 22 year period) to document the rate and trajectory of terrestrial vegetation development. Use of a space‐for‐time substitution in Glacier Bay National Park, Alaska, allowed ‘back‐calculation’ of the age and stage of development of six catchments over 206 years. The high accuracy (89.2%) of the remotely sensed information used in monitoring successional change allowed detection of a high rate of change in vegetation classes in early successional stages (bare sediment and alder). In contrast, later successional stages (spruce and spruce–hemlock dominated forest) had high vegetation class retention, and low turnover. Modelled rates of vegetation change generally confirmed the estimated rates of successional turnover previously reported. These data, when combined with the known influence of terrestrial succession on soil development and sediment availability, suggest how physical and biological processes interact over time to influence paraglacial adjustment following deglaciation. This study highlights the application of remote sensing of successional chronosequence landscapes to assess the temporal dynamics of paraglacial adjustment following rapid deglaciation and shows the importance of incorporating bio‐physical interactions within landscape evolution models. © 2014 The Authors. Earth Surface Processes and Landforms published by John Wiley &amp; Sons Ltd.

Characterizing Pacific halibut movement and habitat in a Marine Protected Area using net squared displacement analysis methods

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 517:229-250 (2014) - DOI: https://doi.org/10.3354/meps11043 Characterizing Pacific halibut movement and habitat in a Marine Protected Area using net squared displacement analysis methods Julie K. Nielsen1,*, Philip N. Hooge2,4, S. James Taggart2,5, Andrew C. Seitz3 1School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 17101 Pt. Lena Loop Rd., Juneau, Alaska 99801, USA 2US Geological Survey Alaska Science Center, 3100 National Park Road, Juneau, Alaska 99801, USA 3School of fisheries and Ocean Sciences, University of Alaska Fairbanks, PO Box 757220, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA 4Present address: Glacier Bay National Park and Preserve, PO Box 140, Gustavus, Alaska 99826, USA 5Present address: 1350 Yulupa Ave. Apt. B, Santa Rosa, California 95405, USA *Corresponding author: julie.nielsen@gmail.com ABSTRACT: We characterized small-scale movement patterns and habitat of acoustic-tagged adult (68 to 220 cm total length) female Pacific halibut during summer and fall in Glacier Bay National Park, Alaska, a marine protected area (MPA). We used net squared displacement analysis methods to identify 2 movement states, characterize individual dispersal patterns, and relate habitat variables to movement scales. Movement states identified for 32 of 43 halibut consisted of (1) a non-dispersive ‘residential’ movement state (n = 27 fish), where movement was restricted to an average movement radius of 401.3 m (95% CI 312.2-515.9 m) over a median observation period of 58 d, and (2) a ‘dispersive’ movement state (n = 15 fish), where movements of up to 18 km occurred over a median observation period of 27 d. Some fish (n = 10) exhibited both movement states. Individual fish demonstrated primarily non-random dispersal patterns including home range (n = 17), site fidelity (return to previously occupied locations following forays, n = 6), and shifted home ranges (n = 5). However, we also observed a random dispersal pattern (n = 4) with an estimated mean ± SE diffusion rate of 0.9 ± 0.05 km2 d-1. Home range size increased with depth but not fish size. Home range locations were associated with heterogeneous habitat, intermediate tidal velocities, and depths <100 m. Observations of non-dispersive movement patterns, relatively small home ranges, and site fidelity for adult females suggest that MPAs such as Glacier Bay may have utility for conservation of Pacific halibut broodstock. KEY WORDS: Movement ecology · Home range · Site fidelity · Net Squared Displacement · Dispersal · Marine Protected Area · Flatfish · Pacific halibut Full text in pdf format Supplementary material PreviousNextCite this article as: Nielsen JK, Hooge PN, Taggart SJ, Seitz AC (2014) Characterizing Pacific halibut movement and habitat in a Marine Protected Area using net squared displacement analysis methods. Mar Ecol Prog Ser 517:229-250. https://doi.org/10.3354/meps11043 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 517. Online publication date: December 15, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Effects of Vessels on Harbor Seals in Glacier Bay National Park

We evaluated the effectiveness of harbor seal (Phoca vitulina)-related vessel regulations in Glacier Bay National Park. We observed 100% compliance with area closures intended to minimize disturbance to dependent pups, yet dependent pups were still present in the inlet after the area was opened to vessels. Compliance with the 463 meter (m) minimum approach distance regulation by vessels was low (22%), although 33% of vessel–seal encounters resulted in disturbance when vessels were still &gt;463 m from seals. Ice cover was the best predictor of disturbance. Our results indicated that vessel regulations might be variably effective due to biological irrelevance, noncompliance, or environmental factors. MPA regulations should be evaluated to ensure achievement of conservation objectives.

Brown bears and wolves scavenge humpback whale carcass in Alaska

Brown bears (Ursus arctos) are generally solitary animals, although they are known to aggregate at concentrated food resources. Using remote cameras, we documented brown bears aggregating while scavenging a whale carcass from 19 May to 17 September 2010 in Glacier Bay National Park, Alaska, USA. Such aggregations have not been reported in Glacier Bay, a recently deglaciated fjord where bear food resources are dispersed and less diverse than in other regions of coastal Alaska. We documented multiple brown bears and wolves (Canis lupus) scavenging the carcass—at times, simultaneously. This study provided a rare opportunity to document brown bear–wolf interactions over several months associated with a large-magnitude resource event with little evidence of aggression between species. Our results suggest that the humpback whale (Megaptera novaeangliae) carcass provided a substantial food resource for brown bears and wolves in Glacier Bay, potentially influencing space use and interspecific interactions.