Browsing by Subject "Predation"
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Item Open Access Investigation of Seal and Dogfish Depredation in Gillnets(2008-04-18T22:36:55Z) Rafferty, AnthonyImpacts of predation by seals and dogfish on fish caught in gillnets has been largely neglected. This is important in Cape Cod’s Fixed Gear Sector because all discarding associated with predation is counted against the sector’s Total Allowable Catch (TAC). This results in a loss of profits for fishermen within the sector. Between June 3rd and July 3rd 2007, sixty-one gillnet hauls were observed during regular commercial fishing activities in order to investigate predation rates of both species. Allometric regression was used in tandem with weight conversion factors to determine the estimated total weight of eaten and discarded fish in each haul. Spatial relationships and predation rates relative to certain environmental variables were also investigated. Results showed that approximately 2,500 lbs of fish was discarded from a total catch weight of nearly 130,000 lbs because of predation by both seals and dogfish. This represented an estimated $2,500 loss from a total catch value of $64,000, signifying a 3.53% loss of the fishermen’s gross profits. The biggest monetary loss was associated with the monkfish catch. With regard to environmental variable significance, there was a correlation between increased net soak duration and increased predation by both species. The water depth at which nets were set was also significant; however, this was only in relation to seal predation with predation events generally occurring between 25 and 31 fathoms. Seal events occurred mainly over clay and, dogfish over a sandy substrate, however, bias may exist in these latter findings based on the predominance of nets being set on sand. Furthermore, spatial investigations highlighted that fishing practices were taking place in closed and restricted areas. Overall, results suggest that amendments need to be made to the NEFMP to ensure a reduction in discarding associated with predation by seals and dogfish. Also, although the gross profit loss appeared low, further investigations involving net profit loss would place these findings in greater context.Item Open Access IS HUMAN PREDATION ON OTHER SPECIES AN ACCOMMODATION OF THE FALL OF CREATION OR PART OF GOD’S INTENDED PLAN FOR CREATION?(2021) Sandoval, Joseph ArmandoThe scriptural witness has indications that it is acceptable to kill animals for food but also indicates that originally human beings were vegetarians and will be yet again when this world is claimed as part of God’s kingdom. This thesis offers a theological analysis of the practice of humans eating animals. Is it an accommodation of humanity’s fallenness after their expulsion from the Garden? Or is it part of God’s design for the world? An in-depth look at the whole of scripture is employed for arguing both sides. Additionally, the thesis offers comparative analysis of a variety of theological approaches to animal rights and animal welfare. The thesis considers scientific revelations about animal’s cognitive abilities for language and problem solving, as well as recent studies on animal grief in order to re-assess the underlying question of ethical relationship between animals and humans. The thesis argues that God has put humanity in a set of circumstances which are meant to encourage understanding of animals as part of its own growth. Specifically, human growth toward the role of being a stewards of creation, that is to say nurturers and not exploiters of God’s creatures. Fallenness is not the issue. But growth is. Thus the provision that allows humanity to kill and eat animals is afforded, while humans still require the ability to kill animals for their own sustenance. What awaits is a time when humanity and animals are in peaceful community with each other, with no death or violence in the world and a full realization of the image of God in humanity.
Item Open Access IS HUMAN PREDATION ON OTHER SPECIES AN ACCOMMODATION OF THE FALL OF CREATION OR PART OF GOD’S INTENDED PLAN FOR CREATION?(2021) Sandoval, Joseph ArmandoThe scriptural witness has indications that it is acceptable to kill animals for food but also indicates that originally human beings were vegetarians and will be yet again when this world is claimed as part of God’s kingdom. This thesis offers a theological analysis of the practice of humans eating animals. Is it an accommodation of humanity’s fallenness after their expulsion from the Garden? Or is it part of God’s design for the world? An in-depth look at the whole of scripture is employed for arguing both sides. Additionally, the thesis offers comparative analysis of a variety of theological approaches to animal rights and animal welfare. The thesis considers scientific revelations about animal’s cognitive abilities for language and problem solving, as well as recent studies on animal grief in order to re-assess the underlying question of ethical relationship between animals and humans. The thesis argues that God has put humanity in a set of circumstances which are meant to encourage understanding of animals as part of its own growth. Specifically, human growth toward the role of being a stewards of creation, that is to say nurturers and not exploiters of God’s creatures. Fallenness is not the issue. But growth is. Thus the provision that allows humanity to kill and eat animals is afforded, while humans still require the ability to kill animals for their own sustenance. What awaits is a time when humanity and animals are in peaceful community with each other, with no death or violence in the world and a full realization of the image of God in humanity.
Item Open Access Relationships Between Vernal Pool Reptile and Amphibian Species Composition and Spotted Salamander (Ambystoma maculatum) Egg Mass Density in the North Carolina Piedmont(2023-04-25) Fajardo, MarisaSpotted salamanders (Ambystoma maculatum) are essential indicators of vernal pool health, yet little research has identified the effects of interspecies interactions on spotted salamander oviposition. In this study, I evaluated the relationships between vernal pool reptile and amphibian species composition and spotted salamander egg mass density within Durham and Orange County. I observed significantly higher egg mass densities in pools with more Salamandrid, Viperid, and Scincid species despite threats of predation. High egg mass densities were also correlated with the presence of early breeding spotted salamanders and more acidic pH levels. Results suggest that spotted salamanders select breeding sites based on environmental conditions, rather than in avoidance of predation or resource competition. These findings are likely influenced by scarcity of optimal breeding habitat within the study area due to history of urbanization and agricultural land use.Item Open Access Water Scarcity, Distribution, and Quality as Drivers of Lemur Behavior(2019) Amoroso, Caroline RuskBecause water is essential for life, when it is scarce, it may be one of the most important drivers of animal behavior. Despite its clear importance, water is relatively poorly studied in terms of its impact on primate behavior, and previous research has been limited to observational studies. This dissertation takes a combined experimental and observational approach to study behavior related to water acquisition in captive and wild lemurs. Specifically, I investigated how several dimensions of water sources influence lemur behavior, including their parasite transmission risk, spatial distribution, and predation risk. In experiments, I manipulated the fecal contamination of water with several species of lemurs in captivity at the Duke Lemur Center, and found that lemurs strongly preferred clean to feces-contaminated water in captivity (Chapter 2). I expanded this initial study to a more comprehensive examination of the impact of water scarcity on the behavior of wild red-fronted lemurs (Eulemur rufifrons) in Kirindy Forest, Madagascar. This wild study population requires drinking water to survive, but water is extremely limited during the dry season. I experimentally manipulated water availability in the habitat by introducing artificial water sources, and I tracked how changes to the distribution of water influenced the ranging patterns of the lemurs recorded by GPS collars. Lemur groups shifted the intensity of their habitat use relative to natural and experimental water availability (Chapter 3). Using a similar experimental approach to the study in captivity, I determined that wild, water-limited lemurs also preferred to drink clean water. Based on lemur groups’ selection of natural water sources as measured with camera traps, wild lemurs also selected water sources with lower fecal contamination more frequently, but with some constraints. Lemurs were more likely to return to waterholes and returned to them after shorter time intervals when they had lower levels of fecal contamination in the areas around them. However, lemurs’ natural waterhole choices reflected that fecal contamination was a secondary factor determining water source selection, behind travel distance (Chapter 4). Finally, I examined how predation risk, i.e. the presence of fossa (Cryptoprocta ferox) and Madagascar harrier hawks (Polyboroides radiatus), influenced red-fronted lemurs’ spatiotemporal patterns of waterhole use. Red-fronted lemurs used waterholes at times of day when predators were least likely to be present (Chapter 5). This study, with its combined experimental and observational approach, identifies water as an important factor that shapes wild primate behavior. I found that lemurs were flexible in their responses to changes in water distribution, parasite risk, and predation risk. I suggest that water should be the focus of future behavioral research in primates, especially given the relevance of water for human evolution and the potential for climate change and human land use to further alter water availability.