Historic and Current Use of Lower Cook Inlet, Alaska, by Belugas, Delphinapterus leucas

Dedicated at-sea surveys for marine birds and mammals conducted in lower Cook Inlet in late July and early August from 1995–99 failed to locate any belugas, Delphinapterus leucas. Surveys covered a total of 6,249 linear km and were conducted in both nearshore and offshore habitats. Sightings included 791 individual marine mammals of 10 species. Both historical data and local knowledge indicate that belugas were regularly seen in summer in nearshore and offshore areas of lower Cook Inlet up until the early 1990’s. Diminished presence of belugas in lower Cook Inlet may be a direct function of reduced numbers but may also indicate changes in habitat quality that may inhibit recovery

A nearsurface, daytime occurrence of two mesopelagic fish species (Stenobrachius leucopsarus and Leuroglossus schmidti) in a glacial fjord

The northern lampfish (Stenobrachius leucopsarus, family Myctophidae) and northern smoothtongue (Leuroglossus schmidti, family Bathylagidae) are mesopelagic fishes, defined by their vertical distribution in the mesopelagic zone (200–1000 m) during daylight hours. Northern lampfish range from the Bering Sea to southern California (Shimada, 1948), where their abundance is highest along the continental slope and decreases over the continental shelf. They are the most abundant species in the mesopelagic zone of the Bering Sea (Pearcy et al., 1977; Sobolevsky et al., 1996), the Gulf of Alaska (Purcell, 1996), and the eastern North Pacific Ocean off Oregon (Pearcy, 1964; Pearcy et al., 1977). Northern smoothtongue also concentrate in areas bordering the continental slope and are widely distributed from southern British Columbia to the Bering Sea (Peden, 1981) and are very abundant in the Okhotsk Sea (Sobolevsky et al., 1996)

Changes in proximate composition and somatic energy content for Pacific sand lance (Ammodytes hexapterus) from Kachemak Bay, Alaska relative to maturity and season.

Abstract kJg to a maximum of 19.68 kJg , and (per g) are higher than adults in late summer. The seasonal food value of adult sand lance to predators varies markedly, but maximum energetic value coincides with important feeding periods for marine mammals, fish, and seabirds. Published by Elsevier Science B. V

Joint spatiotemporal models to predict seabird densities at sea

Introduction: Seabirds are abundant, conspicuous members of marine ecosystems worldwide. Synthesis of distribution data compiled over time is required to address regional management issues and understand ecosystem change. Major challenges when estimating seabird densities at sea arise from variability in dispersion of the birds, sampling effort over time and space, and differences in bird detection rates associated with survey vessel type. Methods: Using a novel approach for modeling seabirds at sea, we applied joint dynamic species distribution models (JDSDM) with a vector-autoregressive spatiotemporal framework to survey data collected over nearly five decades and archived in the North Pacific Pelagic Seabird Database. We produced monthly gridded density predictions and abundance estimates for 8 species groups (77% of all birds observed) within Cook Inlet, Alaska. JDSDMs included habitat covariates to inform density predictions in unsampled areas and accounted for changes in observed densities due to differing survey methods and decadal-scale variation in ocean conditions. Results: The best fit model provided a high level of explanatory power (86% of deviance explained). Abundance estimates were reasonably precise, and consistent with limited historical studies. Modeled densities identified seasonal variability in abundance with peak numbers of all species groups in July or August. Seabirds were largely absent from the study region in either fall (e.g., murrelets) or spring (e.g., puffins) months, or both periods (shearwaters). Discussion: Our results indicated that pelagic shearwaters (Ardenna spp.) and tufted puffin (Fratercula cirrhata) have declined over the past four decades and these taxa warrant further investigation into underlying mechanisms explaining these trends. JDSDMs provide a useful tool to estimate seabird distribution and seasonal trends that will facilitate risk assessments and planning in areas affected by human activities such as oil and gas development, shipping, and offshore wind and renewable energy

HIV-associated neurocognitive disorders in sub-Saharan Africa: a pilot study in Cameroon

<p>Abstract</p> <p>Background</p> <p>The disease burden of human immunodeficiency virus (HIV) - acquired immunodeficiency syndrome (AIDS) is highest in sub-Saharan Africa but there are few studies on the associated neurocognitive disorders in this region. The objectives of this study were to determine whether Western neuropsychological (NP) methods are appropriate for use in Cameroon, and to evaluate cognitive function in a sample of HIV-infected adults.</p> <p>Methods</p> <p>We used a battery of 19 NP measures in a cross-sectional study with 44 HIV+ adults and 44 demographically matched HIV- controls, to explore the validity of these NP measures in Cameroon, and evaluate the effect of viral infection on seven cognitive ability domains.</p> <p>Results</p> <p>In this pilot study, the global mean z-score on the NP battery showed worse overall cognition in the HIV+ individuals. Significantly lower performance was seen in the HIV+ sample on tests of executive function, speed of information processing, working memory, and psychomotor speed. HIV+ participants with AIDS performed worse than those with less advanced HIV disease.</p> <p>Conclusions</p> <p>Similar to findings in Western cohorts, our results in Cameroon suggest that HIV infection, particularly in advanced stages, is associated with worse performance on standardized, Western neurocognitive tests. The tests used here appear to be promising for studying NeuroAIDS in sub-Saharan Africa.</p

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems

Threshold foraging behavior of baleen whales

The authors conducted hydroacoustic surveys for capelin Mallotus villosus in Witless Bay, Newfoundland, on 61 days during the summers of 1983-1985. On 32 of these days they observed a total of 129 baleen whales, including 93 humpback Megaptera novaeangliae, 31 minke Balaenoptera acutorostrata and five fin whales B. physalus. The majority (96%) of whales were observed when mean daily capelin densities exceeded five schools per linear km surveyed (range of means over 3 yr 0-14 schools km-1). Foraging thresholds of baleen whales (7.3, 5.0, and 5.8 schools km-1) varied between years in relation to the overall abundance of capelin schools in the study area during summer (means of 7.2, 3.3, and 5.3 schools km-1, respectively). -from Author

Behavioural ecology of common murre and Atlantic puffin predation on capelin : implications for population biology

Relationships between capelin (Mallotus villosus), common murres (Uria aalge), and Atlantic puffins (Fratercula arctica) were studied at Witless Bay, Newfoundland, during the summers of 1982 to 1984. Capelin occurred inshore from May to August, but abundance peaked during periods of maximal tidal oscillations and increasing water temperatures in late June and early July. From 1982 to 1984, capelin abundance declined by an order of magnitude, but school densities remained similar. Capelin size varied by 30-40% seasonally, and up to 20% annually, partly due to temporal variations in age-class composition of schools. Capelin dominated by weight in diets (4842 items identified) of murres (adult:82.7% and chick:90.8%) and puffins (78.8% and 93.2%), but juvenile cod (Gadus morhua) and sandlance (Ammodytes dubius) were also important prey. Numbers of capelin in bird stomachs declined from 1982 to 1984, and were seasonally correlated with local capelin density; suggesting sigmoidal (Type III) functional responses. Numerical proportions of capelin in diets (from gizzard contents or chick meals) were not correlated with seasonal or annual variations in local capelin density. Variations in size of prey eaten by birds generally reflected natural variations in prey size. Bird diet overlap was extremely high, and diet diversities were low (puffin > murre). Numbers and flock sizes of birds were best correlated with capelin abundance and density, respectively. Murres were best correlated with higher density capelin schools in deeper offshore waters, and formed larger, more aggregated flocks than puffins. Both murres and puffins exhibited sigmoidal (Type III) aggregative responses to capelin density, with murres having a significantly higher prey density threshold. Density thresholds varied with overall capelin density. Murres had a larger maximum foraging range than puffins, and ranges varied annually with capelin abundance. Murre and puffin feeding ecology and behaviour may be best explained within the context of optimal foraging and predation theory. Ecological differences between murres and puffins may be largely due to their differing body sizes (murre > puffin). Implications for population biology of the Atlantic Alcidae are discussed

Juvenile Marbled Murrelet Nurseries and the Productivity Index

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