Franz Mueter results 33
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Phytoplankton communities change in response to environmental conditions, potentially impacting zooplankton through altered trophic interactions. In the Bering Sea, warm and cold stanzas in recent decades correlated with changes in community structure of zooplankton and fish. Attempts to link these trends to primary producers based on patterns in total chlorophyll a (Chl a ) concentration have been unsuccessful. Using Chl a as...
DNA metabarcoding reveals surprisingly diverse diet in under-ice polar cod during autumnNARA Subscribed
Polar cod ( Boreogadus saida ) functions as a key species in the Arctic food web and is one of the most abundant Arctic fishes. Despite its ecological importance, the feeding ecology of juveniles sampled under the sea ice is unknown. In November 2019, at the onset of sea ice formation, sea-ice associated polar cod and zooplankton samples were collected in the Beaufort and Chukchi seas. Stomach contents were highly digested and...
Atmospheric Pressure Rivalry Between the Arctic and Northern Pacific: Implications for Alaskan Climate VariabilityNARA Subscribed
Located at the confluence of the Arctic and North Pacific and with Alaska at its heart, the Pacific Arctic Region (PAR) is a unique and interconnected regional climate system. Significant climatic changes in the PAR are described by a novel, mobile monthly Alaska Arctic Front (AAF) index, which is defined by sea level pressure differences between the migratory cores of the Beaufort High and Aleutian Low. Regional climate varia...
Male sperm whales ( Physeter macrocephalus ) are known to interact with and depredate from commercial longline fishing vessels targeting sablefish ( Anoplopoma fimbria ) in the Gulf of Alaska (GOA). This study aims to better understand their movement patterns and diving behavior in this region, and in relation to depredation behavior. Between 2007 and 2016 a total of 33 satellite tags were deployed on sperm whales interacting...
Environmental Drivers of Nearshore Fish Community Composition and Size Structure in Glacially Influenced Gulf of Alaska EstuariesNARA Subscribed
Coastal ecosystems in Alaska are undergoing rapid change due to warming and glacier recession. We used a natural gradient of glacierized to non-glacierized watersheds (0–60% glacier coverage) in two regions along the Gulf of Alaska—Kachemak Bay and Lynn Canal—to evaluate relationships between local environmental conditions and estuarine fish communities. Multivariate analyses of fish community data collected from five sites pe...
Community assembly theory states that species assemble non-randomly as a result of dispersal limitation, biotic interactions, and environmental filtering. Strong environmental filtering likely leads to local assemblages that are similar in their functional trait composition (high trait convergence) while functional trait composition will be less similar (high trait divergence) under weaker environmental filters. We used two Ar...
The subarctic shelf of the Eastern Bering Sea (EBS) is one of the world's most productive marine environments, exposed to drastic climate changes characterized by extreme fluctuations in temperature, sea ice concentration, timing, and duration. These climatic changes elicit profound responses in species distribution, abundance, and community composition. Here, we examined the patterns of alpha and temporal beta diversity of 15...
Successful management and mitigation of marine challenges depends on cooperation and knowledge sharing which often occurs across culturally diverse geographic regions. Global ocean science collaboration is therefore essential for developing global solutions. Building effective global research networks that can enable collaboration also need to ensure inter- and transdisciplinary research approaches to tackle complex marine soc...
The Arctic Marine Biodiversity Observing Network monitors biological assemblages on taxonomic scales ranging from microbes to seabirds on the northeast Chukchi Sea shelf to improve understanding of their responses to changing environmental conditions, including climate change. Here, we compare two years, 2015 and 2017, the latter characterized by a much larger spatial extent of warmer, more saline Pacific waters within the stu...
Autonomous vehicle surveys indicate that flow reversals retain juvenile fishes in a highly advective high‐latitude ecosystemNARA Subscribed
Summer surveys of the Chukchi Sea indicate that high densities of age‐0 gadid fishes, historically Arctic cod ( Boreogadus saida ) but recently also walleye pollock ( Gadus chalcogrammus ), dominate the pelagic fish community. Adults are comparatively scarce, suggesting that either overwinter survivorship of age‐0 gadids is low, or that they emigrate to other areas of the Pacific Arctic. To examine population movement, we cond...
Social behavior increases in multipod aggregations of southern Alaska resident killer whales ( Orcinus orca )NARA Subscribed
Killer whales ( Orcinus orca ) are highly social and occasionally gather in large aggregations that reach 150 individuals. During 338 encounters with Southern Alaska resident killer whales, we collected 1,352 hr of behavioral data to assess the probability of various behaviors based on season, number of pods present, presence of rarely sighted pods, and number of mitochondrial DNA haplotypes present. A binomial generalized lin...
Multispecies biomass dynamics models reveal effects of ocean temperature on predation of juvenile pollock in the eastern Bering SeaNARA Subscribed
Walleye pollock ( Gadus chalcogrammus ) supports one of the largest commercial fisheries in the world. Juvenile pollock are important forage fish in the eastern Bering Sea (EBS) ecosystem, often representing the largest fraction in the diets of major Bering Sea piscivores. Large variability in the EBS pollock stock biomass in recent years has been attributed primarily to fluctuations in recruitment. It has been hypothesized th...
Effects of the North Pacific Current on the productivity of 163 Pacific salmon stocksNARA Subscribed
Horizontal ocean transport can influence the dynamics of higher‐trophic‐level species in coastal ecosystems by altering either physical oceanographic conditions or the advection of food resources into coastal areas. In this study, we investigated whether variability in two North Pacific Current (NPC) indices was associated with changes in productivity of North American Pacific salmon stocks. Specifically, we used Bayesian hier...