Stormwater runoff from urban and urbanizing areas poses a serious threat to water quality, and unless managed properly will impede efforts to restore the Chesapeake Bay.Water quantity, as well as quality, must be considered, and Low Impact Development(LID) is an innovative stormwater management approach that addresses both. LID seeks to mimic a site's predevelopment hydrologic regime by retaining and treating stormwater at the lot level using small, cost-effective landscape features.The purpose for this study was to identify and rank impediments to the implementation of LID in the Virginia portion of the Chesapeake Bay watershed. This was accomplished by going to LID workshops and distributing a survey to stakeholders in attendance. The survey asked respondents to rank the following impediments to the implementation of LID: site-specific & non-structural, property owner acceptance, pollutant removal benefit, development rules, lack of education, maintenance considerations, flooding problems, and cost. Lack of education was ranked as the most important impediment, with development rules following close behind. Pollutant removal benefit was ranked the least important impediment. A second purpose was to assess whether there is a relationship between a county's growth rate and adoption of Better Site Design principles (BSD) and LID. A Code and Ordinance Worksheet was used to evaluate the development rules of 13 counties (6 high growth, 3 medium growth and 4 low growth) within Virginia's portion of the Chesapeake Bay Watershed. The scores from the worksheets were used to determine if the amount of growth pressure experienced by a county influenced the degree to which they incorporated BSD and LID in their local development codes. Statistical testing revealed that the relationship between growth pressure and score on the Code and Ordinance Worksheet was moderate, at best.

We monitored distribution and abundance of food resources and determined food habits of nonbreeding bald eagles (<i>Haliaeetus leucocephalus</i>) on the northern Chesapeake Bay, as a preliminary step toward examining food-base effects on bald eagle distribution and abundance. To correctly interpret our food habits results, we first examined biases of 2 commonly-used food habits techniques, pellet analysis and food remains collection, through feeding trials with 2 captive bald eagles. Eagles were fed a variety of food items found on the northern Bay. Egested pellet contents and frequency of remains were compared with actual diet. We also examined efficacy of direct observation by observing eagles in high-use foraging areas. We found pellet analysis accurately indicated the species of birds and mammals eaten, but overrepresented medium-sized mammals and underrepresented large carrion in percent occurrence results. Fish were poorly represented in pellets. Eagles rarely produced pellets after eating fish, suggesting that pellet egestion rate, defined as the number of pellets produced per eagle per night, can serve as an index to relative use of birds and mammals. Food remains collection was highly biased toward birds, medium~sized mammals, and large, bony fish. Direct observation was labor intensive and required close proximity of the observer for unbiased identification of food items. Observation may be the only means of documenting eagles' use of small, soft-bodied fish. We used direct observation, pellet analysis, and pellet formation rates to determine bald eagle food habits from December 1986 through April 1988. We monitored fish abundance by gill netting and waterfowl abundance by aerial surveys over this same period. Fish and waterfowl abundance varied reciprocally; waterfowl numbers peaked in winter and fish numbers peaked in spring and late summer. Bald eagles responded to differences in food abundance with diet shifts. Canada geese (<i>Branta canadensis</i>), mallard (<i>Anas platyrhynchos</i>), and white-tailed deer (<i>Odocoileus virginianus</i>) carrion were primary foods from November through February. Cold-stressed gizzard shad (<i>Dorosoma cepedianum</i>) were captured frequently by eagles below a hydroelectric dam on the Susquehanna River in November and December, and also were taken frequently throughout the study area during a winter when ice cover was extensive. Shad were not commonly available during a milder winter. From April through September, bald eagles fed on a variety of fish species, primarily gizzard shad, channel catfish (<i>Ictalurus punctatus</i>), Atlantic menhaden (<i>Brevoortia tyrannus</i>), white perch (<i>Morone americana</i>), American eel (<i>Anguilla rosfrata</i>), and yellow perch (<i>Perca flavescens</i>). The 4 most commonly consumed fish species also were the most commonly gill netted species. At least 25% of all fish taken were scavenged. Live fish were most abundant at the water's surface in shallow water. Bald eagles' use of live fish reflected this availability; water depth at live fish capture sites was less than at sites where fish of dead or unknown status were taken. Eagles foraged most intensively within 1 hour of sunrise. A second smaller peak in foraging activity was observed in early afternoon. / Master of Science

Forested shoreline is important perching habitat for bald eagles (Haliaeetus leucocephalus). Bald eagles hunt, feed and loaf on shoreline perches. I measured trees suitable for bald eagle perches along the northern Chesapeake Bay during 1990-1991 to determine the influence of shoreline perch tree availability on bald eagle distribution. The shoreline was divided into 250 x 50 m segments. A segment was considered used if at least 1 eagle had perched on it during 1985-1992. I determined the number of suitable shoreline perch trees, percent forest cover, and distance from the water to the nearest suitable perch tree for each segment. Segments along the Chesapeake Bay had an average of 1 suitable perch tree per 10 m of shoreline. Shoreline segments used by eagles had more suitable perch trees (P = 0.0008) and a larger percent of forest cover (P = 0.0008). Suitable trees on segments with eagle use were closer to water than suitable trees on segments without eagle use (P = 0.0087). The differences in segments with and without eagle use appear to be largely due to the lack of trees in marshes which were used only seldomly. Marsh had few suitable perch trees, less forest cover and a greater mean distance from water to the nearest suitable perch tree than the other land types (P < 0.0001). These factors are unfavorable for foraging eagles and most marsh segments (66.7%) were unused, probably for this reason. The number of suitable perch trees and the percent of forest cover were lower on developed areas than undeveloped, forested areas (P < 0.01 for both tests). Also the distance from water to the nearest suitable perch tree was greater on developed land than forested land (P < 0.01). Thus, development appears to decrease the availability of suitable shoreline perch trees when compared to forested areas. Logistic regression models were created to predict the probability of eagle use, given the conditions at the time of this study. Varying values of development density, percent forest cover, number of suitable perch trees and distance from water to the nearest suitable tree were inputs used in these models to create curves to predict eagle use under different conditions. These curves indicated that, for a given development density, the probability of eagle use increased as the number of suitable perch trees or percent forest cover on the segment increased. Also, for a given development density, the probably of eagle use increases as the distance to water decreases. / Master of Science

GIS (Geographic Information Systems) and remote sensing techniques were used to predict relationships between bald eagle nest presences and land type, distance to land type and impervious surface cover area. Data plots revealed bald eagle nest presence decreases in response to an increase in area of bareland; increases with an increase in area of forested land; decreases with an increase in distance (m) to shoreline, and decreases in response to an increase in area of impervious surfaces. Logistic regression models identified impervious surfaces as an indicator for bald eagle nest presence (P 24% as unsuitable. Unsuitable area covered 17.82% of the total study area, impacted area covered 13.40%, and, sensitive area covered 68.77%. The projected increase in population in the state of Virginia and subsequent increase in impervious surfaces presents a challenge to the future viability of the Virginia Chesapeake Bay bald eagle population. The threshold analysis identified areas of prime conservation concern for bald eagle nest presence within the defined study area. These areas provide the basis for a conservation management plan and for further scientific study.

This research examined effects of hypoxic environments on blue crabs, Callinectes sapidus in an estuarine environment. Hypoxic conditions were treated as a multiple stressor involving low dissolved oxygen (D.O.), increased carbon dioxide (hypercapnia), and low pH concurrently. The objectives were to: 1) identify hypoxiahypercapnia by monitoring D.O. and pH as an indicator of hypercapnia in shallow regions of the York River, 2) measure blue crab abundance, and 3) describe blue crab responses to hypoxiahypercapnia via field work at Taskinas Creek and lab measurements of respiration. Ambient D.O. and pH were positively correlated in the Taskinas Creek and York River sites (r= .73). Crab abundance (CPUE) was not significantly different among D.O. and pH ranges. It was concluded that hemolymph blood lactate concentration was not considered a good in situ biomarker for exposure to hypoxickypercapnic conditions. Oxygen uptake was not significantly different between normoxic and hypoxic conditions but was significantly affected by pH.

Native oysters have been promoted as a means to improve water quality in Chesapeake Bay. This project added important insights into the potential of oyster aquaculture to process and remove nutrients from Bay waters. Results clarified that nutrient removal of nitrogen (N), phosphorous (P), and carbon (C) through harvest of cultivated oyster biomass can be quantified and modeled with high levels of statistical confidence. A simple, yet accurate, method is now available for estimating the amount of nutrients removed via harvesting aquacultured oysters. Based on model estimates, 106 harvest sized oysters (76 mm TL) remove 132 kg TN, 19 kg TP, and 3,823 kg TC. Previous work suggested that potentially substantial quantities of N may be removed through enhancement of the coupled nitrification-denitrification pathway in sediments as a result of oyster biodeposition. Using 15N and N2/Ar methods to measure N2 production in sediments, encompassing direct denitrification (DNF), coupled nitrification- denitrification, and anaerobic ammonium oxidation (anammox) pathways, at two oyster aquaculture sites and two reference sites (no aquaculture), we found that oyster biodeposition did not accelerate sediment N removal. We estimate sediment N removal rates via N2 production at an oyster cultivation site producing 5 x 105 oysters (1750 m2) to range from 0.49-12.60 kg N yr-1, compared to 2.27-16.72 kg N yr-1 at a reference site of the same area; making the contribution of oyster cultivation to N removal via sediment N2 production inconsequential as a policy initiative for Chesapeake Bay eutrophication mitigation. Molecular approaches and direct abundance measures have improved our understanding of the sediment microbial community response to oyster biodeposition. Overall, sediments impacted by oyster biodeposition had a significantly different denitrifying community composition than sediments a few meters away or at the non-aquaculture reference sites. Bacterial abundance in sediments was determined by site rather than by oyster biodeposition. No apparent effects of oyster biodeposition were evident in nitrifying bacterial abundance patterns at either site, indicating that oyster biodeposition does not enhance coupled nitrification-denitrification by increasing the abundance of nitrifiers in sediments.

The blue catfish, Ictalurus furcatus (Ictaluridae), is ranked among the most invasive, nonnative species of concern in the Chesapeake Bay watershed. This species, intentionally introduced to three major tributaries and a number of impoundments between 1974 and 1989 for sport fishing, has spread into three additional tributaries. Using samples from the introduced tributary populations as a baseline, we evaluated microsatellite genetic variation in light of demographic and ecological data to elucidate the potential sources of the invasive I. furcatus populations. In general, the populations surveyed in the Chesapeake Bay watershed were considerably more inbred (F ranged from 0.03 - 0.27) than four native populations (all F = 0.03) and they exhibited 12% lower allelic diversity than native populations, showing evidence consistent with a founder effect. Lack of evidence for significant bottlenecks combined with high effective migration rates suggested that there may be a great deal more movement of this species within the Bay than was previously thought. Two proposed scenarios for expansion (dispersal from introduced populations and intentional surreptitious introductions) were evaluated. Although not inconceivable, genetic evidence did not support the Bubba mechanism as the primary mode of expansion and dispersal was found to be the most probable mode underlying the recent range expansion. However, a number of characteristics of the population genetic and mixed stock analyses indicate that a separate scenario, escapement from impoundments, is worth investigating as a substantial source of the expansion. The study has important implications for ecosystem-based management because it is the first application of mixed stock analysis to an invasive species.

Few empirical studies exist that compare regulation (R) and fishing crime (VL). The lack of information about R and VL effects stakeholder decision-making. Crime weakens conservation efforts and creates false baseline data. This furthers R and the cycle repeats. The purpose of this correlational study was to determine the statistical association between the number and type of annual commercial blue crab R and VL of the same. The Pearson's R correlation was used to analyze the data because it demonstrated the strength of each relationship. This quantitative study was grounded in enforcement theory. The data was public record and consisted of the number of R and VL issued yearly from the General Assembly of a Mid Atlantic's State Department of Natural Resources (MD-DNR). The intent was to correlate multiple decades, but the earliest available VL data began in 2009. The analysis uncovered divergent patterns. The correlation coefficient of 0.79644 confirmed laws from 2009 correlated positively with 2010 violations. Further analysis revealed a negative correlation for 2010 and 2011 that was indicated by a negative correlation coefficient of -0.3588 and -0.166. The mean average of VL was 12.5%. As restrictions keep increasing, the economic impact on local communities is substantial. This research has the potential to effect positive changes in restrictive harvest practices, record keeping of VL by Natural Resources of this Mid Atlantic State, and harvest reporting practices by crabbers. Sharing the findings with industry stakeholders may stimulate dialogue among stakeholders that answers why one type of regulation was violated more than another, encourage compliance by industry users, and improve conservation efforts to proliferate blue crab. This research contributes to future investigation of often-neglected variables that compromise conservation of blue crab.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 113-121).

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 118 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 109-118).