Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [25]-27).

Orientador: Irene Bastos Franceschini Vicentini / Banca: Maíra Aparecida Stefanini / Banca: Maria Terezinha Siqueira Bombonato / Resumo: O hepatopâncreas está associado ao intestino médio e apresenta diferentes níveis de complexidade dentre as espécies de decápodas. O objetivo deste estudo foi descrever a estrutura histológica do hepatopâncreas de Macrobrachium amazonicum descrevendo características macroscópicas e microscópicas, tais como os tipos celulares que o compõe e a organização de seus túbulos secretores. Adultos de ambos os sexos de M. amazonicum foram coletados, e o hepatopâncreas foi estudado usando-se técnicas histológicas. O hepatopâncreas é um órgão de coloração amarelo-acastanhada, organizado em dois lobos laterais. A estrutura é formada por uma massa de túbulos de fundo cego com espaço intertubular escasso. Cada túbulo secreto r consiste de um epitélio circundado por lâmina basal e células mioepiteliais. Cinco tipos celulares foram observados: célula E (indiferenciada), célula F (fibrilar), célula R (reabsortiva), célula B (vesicular) e célula M (basal). As células E foram observadas na porção distal dos túbulos e são responsáveis pela reposição mitótica das células do epitélio. As células F foram observadas principalmente próximas às células E na região distal. Células R foram observadas ao longo de todo o túbulo secretor, principalmente nas regiões proximal e medial. As células B são abundantes nas regiões medial e distal do túbulo, diminuindo sua freqüência na região proximal. Foram observadas células M ao longo de todo o túbulo secretor, associadas às células R. / Abstract: The aim of this study is to describe the histological structure of the hepatopancreas of Macrobrachium amazonicum, describing macroscopic and microscopic characteristics: cellular types and the organizations of the secretory tubules. Adults of both sexes of M. amazonicum were collected and the hepatopancreas was studied by using histological techniques. The hepatopancreas is a bilaterally bilobed brown-yellowish organ. The structure is formed by a mass of blind tubules, with scarce intertubular space. Each tubule consist of a cylindrical epithelial layers surrounded by a basal lamina and myoepithelial cells. Five cellular types were recognized: E-cells (embryonic), E-¬cells (fibrilar), B-cells (blisterlike), R-cells (resorptive) and M-cells (midget). F-¬cells were observed in the distal end of the secretory tubules and are the mitotic cells that replenish the cells of the epithelium. The F-cells were observed along all the tubule, mainly in the distal region next the E-cells. R-cells were observed in the proximal and medial regions. The B-cells were abundant in the medial and distal regions of the tubule. M-cells were observed along all the tubule associated to the R-cells. / Mestre

Levels of toxic organic pollutants (TOP) were examined in the blue crabs, Callinectes sapidus, of Virginia waters. Alkyl substituted polynuclear aromatic hydrocarbons (ASPAH), thought derived from weathered petroleum, were the most common organic pollutants present. Unsubstituted aromatics, heterosubstituted aromatics, polychlorinated biphenyls (PCB), and DDT metabolites were also detected by the analytical procedure employed. Highest levels of ASPAH were found in crabs from the heavily industrialized Hampton Roads area of the James River. Lower concentrations were detected in crabs from the Pocomoke Sound, the upper James and the Rappahannock River sampling sites. PCB levels were elevated in samples taken from both James River stations. Levels of TOP were generally higher in crabs sampled in June than in September of 1981. Concentrations of pollutants in the tissues and tissue lipid content were correlated. Highest levels of both were detected in the hepatopancreas, followed by egg, ovary and muscle. TOP levels in field samples and in-vivo biotransformation of the model compound benzo(a)pyrene (B(a)P) in the hepatopancreas, during in-laboratory experiments, suggested that differences may exist in the uptake and elimination of pollutants as a function of the sex and maturity of the crabs. It appeared that the metabolism of aromatic hydrocarbons varied with the molt stage of the crabs. A variety of polar metabolites of tritium labeled B(a)P were detected in the hepatopancreas of blue crabs, when examined by normal and reverse phase high performance liquid chromatography. In conclusion, to accurately assess the levels and effects of TOP in biota from the field, several factors must be considered. Among these are the species and tissues examined, the sex, maturity and condition of the individuals selected for analysis, and the location and season of sampling.

Cooperative research utilizing industry vessels represents a viable approach to acquire the data necessary to meet the increasing needs associated with the modern management of marine resources. This dissertation addresses a variety of topics associated with the integration of commercial vessels into the stock assessment of the sea scallop, Placopecten magellanicus. In this study we evaluate the efficacy of utilizing industry vessels with respect to topics that range from rotational closed area survey design, sampling gear evaluation as well as an experiment that broadens the scale of the traditional use of industry vessels in this fishery and provides data to support the use of commercial vessels for surveying sea scallops resource wide. The first paper presents a methodology to evaluate candidate sampling designs for closed area surveys. We simulated scallop populations within a closed area based upon both empirical data and an analysis of the autocorrelation structure of the scallops in that area. From the simulated realizations of the scallop abundance and distribution, three different sampling designs at three levels of sampling were evaluated with respect to bias and accuracy of both mean abundance and variance of the sample mean. The second and third papers take advantage of the ability of commercial vessels to simultaneously tow two dredges. Based on this ability, in the second paper, we estimate the size selectivity of the currently mandated New Bedford Style sea scallop dredge. In addition to estimating the size selective characteristics of this piece of gear, we also estimate the efficiency of the dredge. Both measures are important with respect to correctly estimating the exploitable biomass of sea scallops in rotational sea scallop closed areas. The third paper again used paired data to evaluate the relative changes in the performance of the NMFS sea scallop survey dredge. We utilize a Generalized Linear Mixed Modeling (GLMM) approach to analyzing these data with the goal of characterizing any structural changes in the performance of the dredge that is used to survey both specifically scallop closed areas as well as the entire resource via the annual NMFS time series since the 1970's. The final paper broadens the scale of the utilization of industry vessels and calibrates two of these platforms to the NMFS annual sea scallop survey. We evaluated four separate vessel gear combinations relative to the R/V Albatross IV, throughout the range of the U.S. sea scallop resource and present information to either utilize these vessels to conduct the survey, or at least form a link to a future platform. The results in this dissertation demonstrate that industry vessels represent a feasible option for the collection of sea scallop stock assessment information and present both methods and current information to facilitate their use. These approaches are especially applicable for sea scallops, where the management for this species embraces the spatial characteristics of the underlying population and crafts appropriate management strategies.

This project investigated the feasibility of using the brackish water clam Rangia cuneata as a heavy metal pollution indicator, and further investigated the state of heavy metal pollution in the James River. Rangia cuneata were sampled in the fall of 1972 from the Rappahannock and James Rivers , and meats were analyzed by atomic absorption spectrophotometry for wet weight concentrations of copper, zinc, cadmium and lead. Levels of copper and zinc in Rangia cuneata were shown to be unaffected by clam size, spawning differences, salinity or distance upriver, and substrate grain size. Heavy metal concentrations in the oxidized channel sediments, determined from other studies conducted at the same time, were compared to levels in Rangia cuneata, but no relationships were found. Lead was below detection limits (0.2 ppm) in Rangia cuneata at all stations, and cadmium levels appeared to be consistent in both rivers. Copper was found to increase upriver in the James, indicating an upstream source, and zinc concentrations were found to peak at the mouth of the Chickahominy River. A number of possible causes were cited. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.

Foraminiferal faunas in marshes and distributary channels of the James River estuary, Virginia, disclose several facies. The channel facies, primarily Ammobaculites crassus, and A. sp. A, typical of estuaries in Chesapeake Bay and other brackish areas are readily distinguishable freom the march facies. Marshes are divisible laterally by changes in the relative proportions of marsh species such as Miliammina fusca, Ammoastuta salsa, and Haplophragmoides hancocki.Changes along the longitudinal estuarine salinity gradient are discernable in both tidal creeks and marsh. Channels exhibit a longitudinal gradient from a freshwater thecamoebinid facies through an upper and mid-estuarine Ammobaculites facies to a higher salinity Elphidium assemblage. Marshes are divisible into thecamoebinid, Ammoastuta-Miliammina and Miliammina zones. Macroscopic marsh floral zones along the estuary exhibit changes which are similar to, but do not mirror, changes in foraminiferal facies. Both distributions are responses to salinity and elevation above Mean Low Water. Paleocological inferences are drawn from data on distributions of marsh microfaunas. This dissertation is from the Joint Program Degree from the College of William & Mary and University of Virginia and awarded by the University of Virginia.

No description available.

The identification and delineation of nursery areas and areas of aggregation of north Atlantic sharks has been identified as an important information need for future management efforts. The objectives of this project were to use a fishery-independent method to study the overwintering area of juvenile sandbar sharks, to spatially delineate the Eastern Shore nursery area, and to examine movement patterns and space use within this nursery area. Data from 21 satellite transmitters attached to large juvenile sandbar sharks revealed that these sharks primarily occurred off the outer banks of North Carolina, at deeper depths and colder water temperatures during the overwintering period (after November 1). The data from this project support the size and scope of the closed area currently enacted by the Fishery Management Plan. The Eastern Shore of Virginia was found to be an important primary and secondary nursery area for this population of sandbar sharks. Within this nursery area sharks were most concentrated in Great Machipongo Inlet. Abundance of juvenile sandbar sharks was positively correlated to distance from the inlet and water temperature. Smaller juvenile sharks were more concentrated farther from the inlets and were more prevalent in the southern inlets. Juvenile sandbar shark movements were studied using passive acoustic telemetry. Juveniles tended to spend significantly more time farther from the inlets and their space use was positively correlated to time of day with a greater proportion of time spent in the acoustic array during the night time hours. Tidal currents were positively correlated with small scale movements but were unrelated to overall space use. The sharks tracked returned or remained within the array to a greater extent than would be predicted by random movements alone indicating these animals have some site attachment to these areas. Smaller sharks remained within the array area to a greater extent than larger sharks indicating they likely have smaller activity spaces. This study emphasizes the importance of both the Eastern Shore of Virginia nursery area and the overwintering area that occurs off the central coast of North Carolina as essential habitat for the north Atlantic population of sandbar sharks.

No description available.

No description available.