For data-limited fisheries, length-based mortality estimators are attractive as alternatives to age-structured models due to the simpler data requirements and ease of use of the former. This dissertation develops new extensions of mean length-based mortality estimators and applies them to federally-managed stocks in the southeastern U.S. and U.S. Caribbean. Chapter 1 presents a review of length-based methods from the literature. Common themes regarding the methodology, assumptions, and diagnostics in these length-based methods are discussed. In Chapter 2, a simulation study evaluates the performance of the length-converted catch curve (LCCC), Beverton-Holt equation (BHE), and Length Based-Spawner Potential Ratio (LB-SPR) over a range of scenarios. Although the LCCC and BHE are older methods than LB-SPR, the former outperformed LB-SPR in many scenarios in the simulation. Overall, it was found that the three length-based mortality estimators are less likely to perform well for low M/K stocks (M/K is the ratio of the natural mortality rate and the von Bertalanffy growth parameter; this ratio describes different life history strategies of exploited fish and invertebrate populations), while various decision rules for truncating the length data for the LCCC and BHE were less influential. In Chapter 3, a multi-stock model is developed for the non-equilibrium mean length-based mortality estimator and then applied to the deepwater snapper complex in Puerto Rico. The multispecies estimator evaluates synchrony in changes to the mean length of multiple species in a complex. Synchrony in mortality can reduce the number of estimated parameters and borrows information from more informative species to lesser sampled species in the model. In Chapter 4, a new method is developed to estimate mortality from both mean lengths and catch rates (MLCR), which is an extension of the mean length-only (ML) model. to do so, the corresponding behavior for the catch rate following step-wise changes in mortality is derived. Application of both models to Puerto Rico mutton snapper shows that the MLCR model can provide more information to support a more complex mortality history with the two data types compared to the ML model. In Chapter 5, a suite of mean length-based mortality estimators is applied to six stocks (four in the Gulf of Mexico and two in the U.S. Atlantic) recently assessed with age-structured models. There was general agreement in historical mortality trends between the age-structured models and the mean length-based methods, although there were some discrepancies which are discussed. All models also agreed on the overfishing status in the terminal year of the assessment of the six stocks considered here when the mortality rates were compared relative to reference points. This dissertation develops new length-based assessment methods which consider multiple sources of data. The review guides prospective users on potential choices for assessment with length-based methods. Issues and diagnostics associated with the methods are also discussed in the review and highlighted in the example applications.

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Sea level rise (SLR) has become a serious threat for coastal communities in recent years. Many communities, including South Florida, are already having the security of their daily lives impacted as climate change causes SLR and other environmental impacts to worsen. This study reviews the Miami-Dade Sea Level Rise Task Force Report to determine how this coastal county government views SLR as a threat. Using mixed content analysis to analyze the report qualitatively and quantitatively, the Task Force's recommendations are categorized based on their focus on security, infrastructure, economics, and the environment. One finds the concerns of the people to maintain their property and infrastructure, as well as their access to water and other basic needs, as insurance costs spike and funding becomes more difficult to obtain. Policies will have to be revised using updated scientific studies, modeling, and mapping to mitigate against the worse-case scenarios.

Hazardous waste site remediation cost estimation requires a good estimate of the contaminated soil volume. The United States Environmental Protection Agency (U.S. EPA) currently uses deterministic point values to estimate soil volumes but the literature suggests that probability bounds analysis (PBA) is the more accurate method to make estimates under uncertainty. The underlying statistical theory is that they are more accurate than deterministic estimates because probabilistic estimates account for data uncertainties. However, the literature does not address the problem of selecting an optimal decision point from the interval-valued PBA estimates. The purpose of this study was to identify the optimal PBA decision point estimator and use it to demonstrate that because the PBA method also accounts for data uncertainties, PBA estimates of remedial soil volumes are more accurate than the U.S. EPA deterministic estimates. The research questions focused on determining whether the mean or the 95th percentile decision point is the optimal PBA estimator. A convenience sample of seven sites was selected from the U.S. EPA Superfund Database. The PBA method was used to estimate the remedial soil volumes for the sites. Correlation analyses were performed between the mean and 95th percentile PBA estimates and the actual excavated soil volumes. The study results suggest that the lower bound 95th percentile PBA estimate, which had the best R2-value of 89%, is the optimal estimator. The R2-value for a similar correlation analysis using the U.S. EPA deterministic estimates was only 59%. This confirms that PBA is the better estimator. The PBA estimates are less contestable than the current U.S. EPA deterministic point estimates. Thus, the PBA method will reduce litigation and speed up cleanup activities to the benefit of the U.S. EPA, corporations, the health and safety of nearby residents, and society in general.

Increasing development like roads and houses will alter the future landscape of Vermont. Development provides important resources for people and society, but also results in consequences for wildlife and opportunities for recreation. Managing development requires information on the public's acceptability of development and how acceptability is shaped by information on various consequences. In this study, I examined three questions: 1) What is the public's acceptability of development? 2) Does wildlife information influence public acceptability of development and 3) Is the maximum amount of acceptable development influenced by views about wildlife, involvement in recreation, and demographic factors? I surveyed 9,000 households in Vermont by including a questionnaire which asked about development, wildlife, recreation, and demographics. I assessed acceptability of amount of development using social-norm curves and used parametric significance tests and mixed-effects models to examine the influence of wildlife, recreation, and demographic factors. The survey response rate was 44%. The maximum acceptable amount of development was slightly more than 32 households/km2, and not meaningfully influenced by the broader consequences of development on seven common wildlife species. The public demonstrated a strong preference for clustered development over sprawled development, which became unacceptable at 20 households per km2. Maximum acceptability of development was significantly influenced by views on some species, including bear, bobcat, and fisher, but not by others such as deer, fox, raccoon, and coyote. Similarly, those involved in common forms of outdoor recreation, including birding, ATVing, hunting, fishing and camping, were significantly less accepting of development relative to those not involved in these forms of recreation. Maximum amount of development was also affected by demographic factors, including town density, respondent age, home ownership and location of birth. The results provide a baseline measure of the public's acceptability of development, which can be used to guide decision-making about amount and pattern of development, wildlife management, and efforts to promote recreation in the state.

The following research project examines the effects of polychlorinated biphenyls (PCBs) on the environment and the cultural integrity of the St. Regis Mohawk tribe in the Mohawk Nation of Akwesasne. This indigenous community has been subjected to widespread long-term industrial pollution from nearby toxic hazardous waste facilities and Superfund sites. The Mohawk Nation of Akwesasne has the distinction of being the only tribe whose officially recognized territory straddles the border between the United States and Canada. Using qualitative methodologies, coupled with an interdisciplinary framework, this study successfully engages with Akwesasne community members to explore such issues as bottom-up approaches to addressing complex environmental issues, by gaining a comprehensive understanding of organizational structures and tribal governance networks. This study also identifies a clear parallel between the Mohawk Nation of Akwesasne's struggles and history of environmental justice efforts in the U .S. by articulating the effects of environmental degradation on their cultural integrity, in addition to surfacing themes of resistance and resilience in the community as building blocks for future action. The research project focuses on the place of the community's voice in the transnational public policy response to PCB contamination in the Mohawk Nation of Akwesasne. Three case studies were conducted in environmental organizations on the Mohawk Nation territory: the St. Regis Mohawk Tribe Environment Division, the Mohawk Council of Akwesasne, and the Akwesasne Task Force on the Environment. These environmental organizations have been working to protect the environment for approximately three decades. A case study analysis relies on data collected from interviews with staff members to determine how they organized themselves to address the environmental and social disruption caused by exposure to harmful chemical pollutants. Strong parallels can be drawn as a result of an analysis of environmental justice literature, since native communities have not, traditionally, been included in the scholarly academic literature on the Environmental Justice Movement in the United States. In addition to information gathered from institutional policy actors and related stakeholders, in-depth interviews with community members revealed a community framework for future policy development and action. Finally, the research focuses on how those community voices articulate the impacts of PCB contamination on the natural resources in the area, and as a result, on the ability of the St. Regis Mohawk tribe to maintain their culture, heritage, ceremonies, and traditional way of life.

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One of the main threats to water quality in the Chesapeake Bay is contamination by bacterial loading from point and non-point sources. While only very high levels of fecal bacteria (greater than 200 MPN/100ml) indicate the potential of a health threat to humans from contact with water, lower concentrations (14 MPN/100 ml) make the shellfish from contaminated waters unfit for human consumption. Many nearshore areas that are vulnerable to bacterial contamination also are suitable for the propagation of shellfish, including the hard clam (Mercenaria mercenaria). This is especially true on Virginia’s Eastern Shore, where shallow, sheltered waters with optimal salinity and little pollution support a hard clam aquaculture industry that had an economic impact upwards of $48 million in 2004 (Murray and Kirkley, 2005). Over the past decade, however, development pressures on the Eastern Shore have increased, and land has been converted from forests and fields to subdivisions and strip malls at a faster rate than in the past. Even in the absence of a point source of bacteria such as a wastewater treatment plant, bacterial loads from non-point sources associated with increased land development have the potential to degrade water quality to the detriment of marine life and marine resource users. One area where the conflict between aquaculture and other water qualitydependent uses, and development pressure is building is the Old Plantation Creek watershed on the Eastern Shore of the Chesapeake Bay. Using a GIS-based watershed model to simulate land use and associated fecal bacteria loads, linked to a Tidal Prism Water Quality Model to estimate the disbursement of bacteria throughout the water body, this study predicts that if development continues to the maximum buildout allowed under current regulations it would lead to the condemnation of a large portion of the shellfish growing waters in Old Plantation Creek. By coupling this linked watershed-water quality model with an economic Input/Output (I/O) model, it was possible to determine the economic impact of those condemnations to the aquaculture industry and the economy of Virginia.

The collection of fecal coliform (FC) monitoring data in shellfish growing waters is primarily to assess public health risks from consumption of contaminated product. The data is also commonly used to assess the potential sources and loads of bacteria entering the aquatic system. This project is intended to extend traditional methods of developing these assessments, by applying an inverse modeling approach to improve the estimation of FC loads in the small watersheds typically contributing to shellfish growing waters in Virginia. Many fecal contamination studies in lower Chesapeake Bay, Virginia, have conveniently focused on analyses over relatively small spatial and temporal scales. The potential sources of bacteria are numerous and the magnitude of their contributions is commonly unknown (Hyer and Moyer, 2004). The effects of stochastic events merely complicate the already difficult task of quantifying sources and loads in an inherently variable system (White et al., 2008). Instead of identifying and quantifying individual fecal bacteria sources, like deer or raccoons or domestic animals, it is herein proposed to analyze spatial and temporal patterns of fecal contamination on relatively large scales and quantify FC loadings based on land cover. The result would make it easier for managers to assign land-cover-based accountability to restore fecal contaminated environments. Monitoring of FC concentrations throughout Virginia by the Division of Shellfish Sanitation (DSS) provided an opportunity to analyze FC levels from 1984 to the present and quantify FC loadings by type of land cover. There are three aspects in this study---spatial analysis of FC data, temporal analysis of FC data, and FC loadings quantification based on the findings from spatial and temporal analyses. GIS tools and a variety of statistical methods are used in combination with an inverse modeling approach. The modeling method was based on some basic concepts incorporated in the Watershed Management Model and the Tidal Prism Model currently used to develop Total Maximum Daily Load (TMDL) models for Virginia waters. The core contributions of this dissertation are: (1) This study provided a thorough examination of FC monitoring data in Virginia coastal waters and described how contamination levels are expressed at different spatial and temporal scales. Analyses examined tidal effects, regional effects, land condition effects, and climate effects. Results not only inform management decisions, but also provide guidance for the subsequent quantification of fecal bacteria loadings. (2) Fecal bacteria loadings are quantified as a function of land cover. The model developed in this study avoids the problems associated with using highly varied and poorly documented FC production rates and population numbers. Although the model is simple, the magnitude of Fecal Coliform Event Mean Concentration (FCMC) values based on land covers effectively distinguished the seasonal FC loadings.