Title of Document: HISTORICAL EFFECTS OF FISHING ON AGE STRUCTURE AND STOCK MIXING IN NORTHWEST ATLANTIC BLUEFIN TUNA Matthew Ryan Siskey, Master of Science, 2015 Directed By: Professor David H. Secor Marine Estuarine Environmental Sciences Bluefin tuna support important fisheries in the Northwest Atlantic Ocean, which have declined in yield from intense, size-selective exploitation. Age struct...

[1] More frequent western atmospheric circulation over Europe results in increased precipitation in winter, and could result in increasing river discharges. We made a quantitative assessment of the impact of variation in atmospheric circulation, defined by the frequency of western circulation in the Großwetterlagen classification system and the North Atlantic Oscillation (NAO) index, on variati...

The question of whether ecosystem process studies can be made relevant to new, emerging management strategies to achieve ecosystem sustainability on U.S. Federal lands is addressed by examining a small sample of studies underway in the Pacific Northwest and Alaska. Processes being studied by many researchers—other than those directly associated with habitat creation— appear largely unrelated to...

Gray wolves (Canis lupus) were once widespread throughout most of North America including the Pacific Northwest. Wolves were extirpated from the Pacific Northwest in the early 20 century and have been absent for over 60 years. The success of reintroduction efforts in Idaho and the greater Yellowstone area, however, has caused wolf populations in these regions to rise dramatically, giving way to...

A strong cohort of young European green crabs (Carcinus maenas) appeared in North American embayments from Oregon to the west coast of Vancouver Island following the strong El Niño of 1997/1998. Unusually, strong north-moving coastal currents transported crab larvae from established source populations in California to the Pacific Northwest. Since then, both coastal transport and recruitment of ...

BACKGROUND Nigeria continues to struggle in its efforts to eliminate circulating live polioviruses using oral poliovirus vaccine (OPV). METHODS We modeled population immunity, and we estimated cases and the timing of transmission die-out for numerous policies that could accelerate the elimination of wild poliovirus type 1 (WPV1) and help Nigeria manage the risks of circulating vaccine-derived...

The coastal marine environment of the Northwest Atlantic contains strong environmental gradients that create distinct marine biogeographic provinces by limiting dispersal, recruitment, and survival. This region has also been subjected to numerous Pleistocene glacial cycles, resulting in repeated extirpations and recolonizations in northern populations of marine organisms. In this study, we exam...

Dryland ecosystems cover more than 30% of the terrestrial area of China, while processes that shape the biogeographic patterns of bacterial and fungal β-diversity have rarely been evaluated synchronously. To compare the biogeographic patterns and its drivers of bacterial and fungal β-diversity, we collected 62 soil samples from a typical dryland region of northwest China. We assessed bacterial ...

We investigated the prevalence of multidrug resistance, production of extended-spectrum β-lactamases (ESBLs), and presence of class 1 and 2 integrons in 150 clinical isolates of Klebsiella pneumoniae from northwest Iran by performing phenotypic confirmatory tests and polymerase chain reaction (PCR) analysis. Of the 150 isolates, 149 (99.3%) were multidrug resistant (MDR). Of the MDR isolate...

An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a...