Mortality

The reproductive success of leatherback turtles (Dermochelys coriacea) is typically the lowest of the seven sea turtle species. Why this vital rate is decreased has remained unanswered for nearly a century. Recently, detailed postmortem examination of leatherback hatchlings identified muscular pathologies that suggested possible selenium deficiency. High bodily burdens of mercury compounds are associated with selenium depletion. Selenium is a necessary detoxifying nutrient that itself can be toxic at elevated concentrations. Mercury compounds are toxicants with no known biological function. High bodily concentrations of mercury can be detrimental to marine organismal health, reproduction and survival, both directly and indirectly through inducing selenium depletion. The goals of this dissertation are to evaluate several related hypotheses to explain low leatherback nest success. ... Because leatherbacks take in high volumes of prey, high tissue concentrations of mercury and selenium can result. This study provides the first evidence that chemical contaminants may explain low reproductive success in leatherback sea turtles.

This dissertation focuses on using one tangible component of filicide, the method or weapon used by a parent to kill a child, as a means by which to understand parental psychology. An evolutionary psychological perspective (e.g., Buss, 2004; Bjorklund & Pellegrini, 2002; Daly & Wilson, 1988; Tooby & Cosmides, 1992) can provide insight into our understanding of filicide. Questions that have not been asked by previous researchers may come to the fore by using an evolutionary perspective as a guide for investigating filicide and its surrounding circumstances and contexts. I present the results of three empirical studies using archival data on filicides recorded in Chicago, Illinois. In Study 1, I present the results of an investigation of parental psychological differences evidenced by the methods of filicide, for filicides recorded between 1965 and 1994. The key results of Study 1 are: (a) while overall (i.e., non-genetic and genetic parents combined), beating was the method of filicide used most often, the percentage of filicides committed by non-genetic parents by beating significantly exceeded the percentage of filicides committed by genetic parents; (b) in contrast, the percentage of filicides committed by non-genetic parents by asphyxiation was significantly less than the percentage of filicides committed by genetic parents. In Studies 2A and 2B, I present the results of an investigation using the 1965-1994 dataset as well as a dataset of filicides-suicides recorded between 1870 and 1930. The key results of these two studies indicate that filicide-suicide may be more likely to occur in certain contexts (e.g., multiple-victim killings) and in certain circumstances (e.g., following paternal filicide). In the final chapter, I discuss the key findings, identify limitations of the current research, and present several future directions for research.

In the Eastern United States, the Florida coastline provides 85% of all nesting sites for the green (Chelonia mydas), leatherback (Dermochelys coriacea), and loggerhead (Caretta caretta) sea turtles. Palm Beach County beaches experience some of the highest nesting frequencies, but recreational use of the beaches has increased threats like raccoon predation. The Gumbo Limbo Nature Center (GLNC) in Boca Raton (founded in 1984) keeps records of nests and predators to the nests. I analyzed 4554 GLNC nest records from 2002-2007 to examine whether raccoon predation of turtle nests was most prevalent in areas of high human impact. I found that raccoon predation occurred at significantly higher rates in areas with public access to the beach than in areas without such access (high access: 50.8%, low access: 14.4%, overall: 36.4%). This suggests the necessity of increased protection of nests in areas of high access for the preservation of nesting populations.