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- Creators: Arizona Board of Regents
Description
Globally, the incidental capture of non-target species in fisheries (bycatch) has been linked to declines of ecologically, economically, and culturally important marine species. Gillnet fisheries have especially high bycatch due to their non-selective nature, necessitating the development of new bycatch reduction technologies (BRTs). Net illumination is an emerging BRT that has shown promise in reducing bycatch of marine megafauna, including sea turtles, cetaceans, and seabirds. However, little research has been conducted to understand the effects of net illumination on fish assemblages, including bony fish and elasmobranchs (i.e. sharks, rays, and skates). Here, I assessed a 7-year dataset of paired net illumination trials using four different types of light (green LEDs, green chemical glowsticks, ultraviolet (UV) lights, and orange lights) to examine the effects of net illumination on fish catch and bycatch in a gillnet fishery at Baja California Sur, Mexico. Analysis revealed no significant effect on bony fish target catch or bycatch for any light type. There was a significant decrease in elasmobranch bycatch using UV and orange lights, with orange lights showing the most promise for decreasing elasmobranch bycatch, resulting in a 50% reduction in bycatch rates. Analysis of the effects of net illumination on elasmobranch target catch was limited due to insufficient data. These results indicate that the illumination of gillnets may offer a practical solution for reducing fish bycatch while maintaining target catch. More research should be conducted to understand the effects of net illumination in different fisheries, how net illumination affects fisher profit and efficiency, and how net illumination affects fish behavior. Further optimization of net illumination is also necessary before the technology can be recommended on a broader scale.
ContributorsBurgher, Kayla Marie (Author) / Senko, Jesse (Thesis director) / Throop, Heather (Committee member) / School of Life Sciences (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The purpose of this study is to spark a discussion for engineers and their firms to consider the impact of border barriers on wildlife. The focus of this study is to consider if or how engineers make those considerations, such as through design modifications. Barriers block wildlife migration patterns, disabling them from life-sustaining resources. This is particularly important due to an increasing trend in habitat loss, urban development, and climate change. During literature analysis of border barrier impacts, and outreaching to relevant organizations and individuals, there was little to no public documentation or discussion from the engineering community found. Discussion that was found is included in this study, but the lack of connection between conservation and engineering professionals is eminently profound. Therefore, the analysis of studying engineering design considerations additionally studied the relationship between environmental and engineering professionals. Types of research included involves literature analysis of journal articles, reports, project plans for construction, and environmental laws pertinent to wildlife impact.
ContributorsMcMillin, Kaci (Author) / Karwat, Darshan (Thesis director) / Senko, Jesse (Committee member) / Engineering Programs (Contributor) / Environmental and Resource Management (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Human consumption of sea turtle eggs, meat, and other products is considered to be a major threat to sea turtle populations worldwide. Declining populations are often attributed to anthropogenic pressures despite evident additional pressure from natural processes; however, depredation by natural or feral species such as raccoons, crabs, and dogs are often unknown. A popular tool for the conservation of marine turtle eggs is hatcheries, but their protection is limited by factors such as carrying capacity and timing or location of nests. The Rescue Center for Endangered Marine Species (CREMA) runs four sea turtle conservation projects on the nesting beaches of the Southern Nicoya Peninsula in Costa Rica, where the predominant nesting activity is from Olive Ridley turtles (Lepidochelys olivacea), followed by sporadic Green (Chelonia mydas), Leatherback (Dermochelys coriacea), and Hawksbill turtles (Eretmochelys imbricata). Two of these nesting projects are based in Costa de Oro and San Miguel, which are adjacent beaches divided by an estuary. Both projects use a hatchery where nests are usually relocated; however, when the hatchery is not available, nests are either relocated or left in situ at the beach. The aim of this study is to: 1) compare human harvest and depredation rates of nests relocated and left in situ. We reviewed data collected from 2012 to 2018 of nests relocated to a hatchery and left in situ at both nesting sites, and these data represent nesting conditions prior to relocation to a hatchery. We found that the nesting beach at Costa de Oro exhibits high rates of human harvest, which has decreased since the conservation project was established, while San Miguel exhibits comparatively low egg harvest but much higher depredation. Egg harvest in Costa de Oro decreases from approximately 50% of all nests in 2013 to 15% in 2018 while depredation on both beaches fluctuates year to year. Our results demonstrate that different pressures impact nesting beach success in the Southern Nicoya Peninsula along with natural threats, possibly due to contrasting community values and human populations. San Miguel has been protecting nests for over 20 years, whereas the Costa de Oro project only began in 2012. It also important to consider that depredation on the San Miguel nesting beach may be increased by human pressure such as in the case of domesticated animals, especially when the human population in San Miguel is consistently higher than in Costa de Oro. Persistence of depredation and human egg harvest alongside conservation efforts exhibit the prevalence of these pressures and suggest increased pressure if measures such as nightly patrols and hatchery protection were not utilized. We suggest a continuation of hatchery and patrol based conservation efforts as well as community outreach to attempt to merge cultural values with sea turtle conservation.
ContributorsReavis, Janie (Author) / Senko, Jesse (Thesis director) / Smith, Andrew (Committee member) / Barrett, The Honors College (Contributor)
Created2019-05
Description
As human populations continue to expand, interactions with wildlife are expected to increase due to destruction of land and global climate change threatening native habitats. Established areas of protection are becoming essential to species survival and biodiversity protection. National Parks (NP) are a globally ubiquitous method employed to protect wildlife and habitats. Often NPs are mosaics of relatively small protected areas in a “sea” of human-dominated landscapes, and these remaining habitat “islands” are becoming essential to preventing species extinction. However, the establishment of a NP can lead to increased human-wildlife conflicts (HWC) and disenfranchisement of local communities, particularly along their borders. We conducted semi-structured interviews in six different countries to better understand the nature of HWCs at the borders of major NPs: (1) Khao Yai NP, Thailand; (2) Myall Lakes NP, Australia; (3) Chitwan NP, Nepal; (4) Kruger NP, South Africa; (5) Chingaza NP, Colombia, and (6) Yellowstone NP, United States. We evaluated affinity to wildlife, perception of conflicts, management success, and potential solutions at each park to better understand the global nature of HWCs.We also evaluated these data in relationship to the Human Development Index (HDI) to determine if there was a correlation between development and conflict issues. We found the intrinsic value of wildlife to not markedly differ between countries. Conflict was perceived as higher in the United States and Australia but was known to be of greater intensity in Nepal and South Africa. Management of NPs was well-regarded with a slight decrease from less-developed countries to more-developed countries, with solutions that were creative and unique to each region. Results appeared to be related to shifting baselines between countries and also to equivalency in a cross-cultural assessment. When these theories are taken into account, the complexity of HWCs globally is better understood. As our world continues to expand and NPs become some of the only contiguous native habitat and refuges for wildlife, it is important to understand the complex relationships occurring at the interface between natural and human communities and to explore effective solutions to these problems.
ContributorsRagan, Kinley Ann (Author) / Schoon, Michael (Thesis director) / Schipper, Jan (Committee member) / Senko, Jesse (Committee member) / School of Life Sciences (Contributor, Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Social behavior embodies a central tenet of biology yet social interactions remain fairly undocumented for marine turtles. Marine turtles have been studied extensively yet the importance and prevalence of social behaviors has largely been overlooked within the taxon as a whole. Through this project, new evidence suggests that marine turtles, specifically Hawksbills, may not be as solitary as initially believed yet display a variety of social behaviors. These behaviors suggest that more complex social behaviors exist throughout the taxon and marine turtles may be more social than initially believed. These findings have important conservation management implications and encourages more research into turtle behavior.
ContributorsJohnson, Corinne Eva (Author) / Senko, Jesse (Thesis director) / Gaos, Alexander (Committee member) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1939
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1944
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1945
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher, Publisher)
Created1948
ContributorsMarine Biological Laboratory (Woods Hole, Mass.) (Publisher) / Arizona Board of Regents (Publisher)
Created1955