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  • Thumbnail for Does whaling make cents? : A bioeconomic model of the Antarctic minke whale and the Japanese whaling industry
    Does whaling make cents? : A bioeconomic model of the Antarctic minke whale and the Japanese whaling industry by Buchanan, Samuel Prescott

    Japan's whaling fleet and environmental organizations are clashing in the Antarctic Ocean as Japan continues to conduct lethal scientific research on whales, specifically on the Antarctic minke whale (AMW). This conflict and issues surrounding other cetaceans have received substantial media attention in the past few years due to the Sea Shepherds Society's television show entitled Whale Wars and the movie The Cove. These productions succeeded in spreading awareness of Japan's lethal research on whales and harvests of dolphins, but insufficiently explained why Japan is engaging in practices that damage her international reputation. These media productions do not provide bioeconomic analysis modeling whether or not the species is threatened by Japan's actions nor the economics of whaling and Japan's market for whale products. Scientific articles related to the biology of whales, and historical, political, and cultural investigations that provide the foundation for the whaling conflict do not explore if Japan's lethal scientific research threatens the AMW with extinction nor explore the economics of Japan's whaling industry and domestic market if commercial whaling were to resume. This thesis aims to answer these questions by constructing a bioeconomic model composed of biological parameters and data from Japan's whaling fleet to estimate various sustainable catch yields and the corresponding AMW population sizes, Japan's seasonal effort in catcher-boat hours, and seasonal sustainable revenues. The eventual equilibrium population and sustainable catch yield if Japan maintains its current harvest effort, the maximum sustained yield, the condition of zero net revenue, and the condition in which the discounted total present value for all future whaling revenue is achieved will be explored in particular. The results conclude that Japan's current scientific research does not endanger the AMW, and furthermore concludes that whaling is not only profitable, but the industry capacity, high costs, and shrinking domestic demand discourage overharvesting that could lead to the collapse of the species

  • Thumbnail for Geophysical evidence for englacial brine associated with Blood Falls, McMurdo Dry Valleys, Antarctica
    Geophysical evidence for englacial brine associated with Blood Falls, McMurdo Dry Valleys, Antarctica by Badgeley, Jessica

    Ground-penetrating radar (GPR) images of Taylor Glacier, in the McMurdo Dry Valleys, Antarctica, reveal an englacial drainage system near this polar glacier’s terminus at Blood Falls. Blood Falls is the surface manifestation of episodic releases of subglacial, iron-rich, hypersaline, microorganism-bearing brine. Locating englacial brine near Blood Falls would allow us to extract unoxidized brine in order to better understand the geochemistry and microorganisms as a proxy for life on other planets. In the current study, we collected a grid of GPR transects immediately upglacier from Blood Falls to locate the path by which brine surfaces and to inform future drilling operations in search of subsurface brine. Additionally, this study explores the extent of the subglacial and englacial brine reservoirs and seeks to refine hypotheses about the mechanisms driving the brine to the surface. In each of the GPR profiles, we found an englacial scattering zone located above a break in the basal-ice reflection. Downwarping of the basal-ice reflection on either side of the break and the break itself indicate that the scattering zone has slowed down the electromagnetic waves and prevented their further propagation into the glacier. We interpret this scattering zone as evidence of water-saturated and/or salty ice. A three-dimensional plot of the scattering zones visible on the profiles reveals a linear trend upglacier from Blood Falls nearly paralleling previously active brine-releasing cracks. Our evidence suggests that the zone is a recently or currently active englacial brine reservoir. In 2014, a team drilled near the area and successfully extracted pressurized brine ~16 m deep and upstream from Blood Falls at -7.1°C within surrounding ice of ~-17 °C. This brine temperature is consistent with the theoretical basal temperature of -7.8 °C that Hubbard et al. (2004) modeled near their hypothesized brine source 3-6 km upglacier from the terminus using geothermal heat flux and friction caused by ice deformation. Further study of the GPR data has allowed us to better understand the extent and movement of subglacial brine to the surface. Our cross-terminus traverse GPR transect shows that the subglacial brine reservoir may, in some form, extend all the way to the terminus and allow continuous brine release into Lake Bonney. As the subglacial brine surfaces, our data and analyses confirm hypotheses that it follows favorable pressure gradients up through surface cracks that penetrate the brine reservoir.