Typescript. / Bibliography: leaves [161]-173. / xii, 173 l illus., tables

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xv, 239 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph.D.)--Oregon, Dept. of Biology Vita Bibliography: l. 135-144

Thesis (M.S.)--Oregon, Dept. of Biology Vita Bibliography: l. 54-59

Orientador: Maria Lúcia Negreiros Fransozo / Banca: Valter José Cobo / Banca: Laura Lopez Greco / Banca: Marcos Tavares / Banca: Daniela Carvalho dos Santos / Resumo: A maturidade sexual é um evento, freqüentemente, marcado por mudanças morfológicas, fisiológicas e comportamentais, indicando a transição da fase juvenil para adulta. Neste trabalho estudou-se a maturidade sexual dos caranguejos Uca vocator, U. thayeri e U. maracoani, comparativamente, baseando-se na análise dos estágios de desenvolvimento gonadal. Os caranguejos foram coletados por meio da técnica de amostragem por esforço de captura (2 pessoas/30 minutos), no período de maré baixa, desde maio/03 a dezembro/04, nos manguezais dos rios Cavalo e Ubatumirim, em Ubatuba/SP e rio Jabaquara, em Paraty/RJ. Todos os caranguejos obtidos foram mensurados quanto à largura da carapaça (LC) e os estágios de desenvolvimento gonadal (macroscópico) foram registrados. Consideraram-se como jovens todos os espécimes com gônadas imaturas e rudimentares, enquanto como adultos aqueles com gônadas nos demais estágios de desenvolvimento (em desenvolvimento, desenvolvidas, avançadas e esgotadas). Os caranguejos foram agrupados em classes de tamanho (amplitude de 1,0 mm de LC) e, para cada classe, determinou-se a porcentagem de caranguejos jovens e adultos. Utilizou-se a equação logística para a determinação do tamanho da maturidade sexual e a técnica dos mínimos quadrados para o ajuste da mesma. Calculou-se, também, o tamanho relativo do início da maturidade sexual (RSOM). O tamanho no qual 50% dos machos e fêmeas encontravam-se maduros foi de, respectivamente: 12,3 e 12,7 mm para U. vocator; 12,5 e 15,5 mm para U. thayeri e 19,0 e 22,3 mm para U. maracoani. Os resultados do RSOM alcançaram, para machos e fêmeas, respectivamente: 0,44 e 0,54 para U. vocator; 0,44 e 0,54 para U. thayeri e 0,42 e 0,55 para U. maracoani. Estes resultados indicam uma razoável similaridade no tamanho da maturidade sexual das... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Não disponível. / Doutor

Rivers all over the world have supported the growth of human civilization since the first towns appeared some 7000 years ago. As a result of this growth and the diversification of activities, most of the world’s rivers have been negatively affected. Freshwater is probably the most important resource of mankind. Not only is it vital for terrestrial life but we consume water in such a range of activities that it can aptly be regarded as a ‘pillar of our civilization’. The development of water conservation recycling and management plans is therefore seen as vital. Cohen (1995) has recently highlighted the importance of freshwater to the future of mankind and in this context it is becoming increasingly important to view water as an economic resource in its own right. Being a third world country, South Africa is a developing country with a constant increase in population size. With the increase in the population, it is accompanied by increasing and expanding mining and industrial sectors. Various metals resulting from these sector’s activities are common pollutants in the rivers of South Africa. Although some metals are essential elements that are necessary for normal growth and metabolism in organisms, all metals can become toxic at elevated levels and therefore the monitoring of the freshwater systems is necessary in order to protect the environment and ultimately to protect humankind. Aquatic invertebrates appear to be excellent biological monitors of heavy metal pollution. They are more tolerant of metals than fish, they accumulate metals in relative proportion to the metal concentration in the water, and they concentrate the metal by some predictable, reproducible factor. However the life cycle of aquatic insects are short which limits the value in bioaccumulation studies. In contrast, crabs are relatively long lived and form an integral part of the food chain, as they are vital components in the diet of several animal species including humans. In the present study an integrated approach was employed in order to investigate the metal pollution in the Klip River, Gauteng. Selected physico-chemical characteristics of the water and sediment were analysed, as were the levels of metals bioaccumulated by the freshwater crab, Potamonautes warreni. Different biological aspects were investigated to identify the natural course of the life cycle, including moulting and reproductive cycles, relative abundance and age structure, as well as several behavioural patterns of this crab species. Water and sediment samples were collected from the Klip River and Sedaven Dam (reference locality) every month from August 1997 up to August 1998. Water quality data revealed that although the quality of the water at all sampling localities were relatively high, Lenasia (locality 1) and Dirk Fourie Stadium (locality 4) appeared to be more impacted than the rest of the sampling localities including the reference locality. Results of the metal analysis in the water samples indicated that levels of zinc, iron, manganese and chromium were below the suggested South African guideline values (laid down for the protection of aquatic life) and that elevated levels of cadmium, lead and aluminium were recorded at localities 1,3 and 4. Results of the metal analysis in the sediment samples indicated that there were elevated levels of zinc, lead, iron, manganese, chromium and aluminium at localities 1 and 2. Potamonautes warreni individuals were sampled every month to coincide with the water and sediment samples and the metal concentrations were determined. The results of this investigation showed that elevated levels of zinc, cadmium, lead, iron, manganese, chromium and aluminium was recorded at locality 1 and this indicated that this locality is subjected to above standard discharge. At locality 3 elevated levels of zinc, cadmium and chromium was recorded and at localities 4 and 5 elevated levels of iron and aluminium was recorded. The results of the present study indicates that metal levels in P. warreni are indicative of the environmental levels of metals to which these crabs are exposed. Higher metal levels as compared to the habitat were found in the organisms at all localities. Locality 1 had a higher environmental level than the rest of the localities. Therefore, these organisms are useful bioaccumulative indicators and should be incorporated into biomonitoring programs in conjunction with fish. It must be stressed that further studies be done on the mechanisms of regulation and elimination of certain metals from the body of P. warreni and on sublethal effects of metals on the physiological processes such as reproduction and growth, especially in juvenile crabs. / Prof. G.J. Steyn

M.Sc. / South Africa is a developing country in which the rapid increase in population size is accompanied by expanding mining and industrial sectors. All these factors have resulted in an increase in the demand for good quality water, but various anthropogenic activities continually result in pollution of the freshwater reserves in the country, via either diffuse or point sources. Metals resulting from both mining and industry are common pollutants of South African aquatic systems. Although some are essential elements that are necessary for normal growth and metabolism in organisms, all metals can become toxic at elevated levels, thus resulting in either lethal and sublethal effects. Aquatic organisms can also bioaccumulate metals thereby transferring them to their predators, including man. Monitoring of freshwater systems is thus necessary in order to protect the environment from these toxic substances, and ultimately to protect mankind. Most monitoring programmes should use an integrated approach in which both physico-chemical and biological aspects are monitored. The present study employed an integrated approach in order to investigate the state of metal pollution in two water bodies that are subjected to differential levels of metal contamination. Selected physico-chemical characteristics of the water and sediment were analysed, as were the levels of metals bioaccumulated by the Freshwater River crab, Potamonautes warreni. The specific object of this study was to assess the potential of P. warreni as a suitable bioaccumulative indicator of metal pollution in the aquatic environment. Water and sediment samples were collected from Germiston Lake and Potchefstroom Dam every alternate month between February 1995 and February 1996. Water quality data revealed that although the quality of the water at both sites was relatively high, Germiston Lake appeared to be more anthropogenically impacted than Potchefstroom Dam. Analysis of metal levels in the water and sediment indicated that while levels of copper, manganese, nickel, lead and zinc were higher in Germiston Lake, calcium and iron were present in higher concentrations in Potchefstroom Dam. Cadmium levels differed little between the two sites. With the exception of iron in Potchefstroom Dam, nickel in Germiston Lake, and zinc at both sites, all of the physical and chemical characteristics of the water from the two sites were within the boundaries of the South African guideline values laid down for the protection of aquatic life. Potamonautes warreni individuals were also collected every alternate month, and metal concentrations in these organisms were determined using atomic absorption spectrophotometry. The results of this investigation showed that metal levels in these organisms did tend to reflect those in the environment, with lower levels of calcium and iron and significantly higher (p < 0.05) levels of copper, manganese, lead, nickel, and zinc in P. warreni from Germiston Lake. Cadmium concentrations detected in these crabs were essentially the same at the two sites. All metals, except for cadmium, were influenced by the size of the crabs at one or other site, but never at both, thus suggesting that the presence of size-related trends is influenced by ambient metal levels in the system. Iron and lead concentrations in P. warreni from Potchefstroom Dam were the only metals that were influenced by the sex of the organisms, with higher levels found in female crabs. The results of the present study clearly indicate that metal levels in P. warreni are indicative of the environmental levels of metals to which these crabs are exposed since higher metal levels were found in the organisms from the site that had higher environmental metal levels. These organisms have proven to be useful bioaccumulative indicators of metal pollution in the aquatic environments from which they were captured, and they should therefore be incorporated into biomonitoring protocols. It must, however, be stressed that further research is required to increase our database on metal levels in these crabs from different aquatic systems.

Hemigrapsus oregonensis and Hemigrapsus nudus, two beach crabs common on the Pacific Coast of North America, show considerable variation in numbers, and species dominance from place to place. To determine why this should be so, a number of experiments were performed, and observations made to determine what are the morphological, and physiological differences between the two species, and how the crabs would be affected by the different physical conditions prevailing in different places. In general, it appeared that H. nudus could not tolerate muddiness of the substrate, while H. oregonensis tended to be eliminated from clean areas by predators. The abundance of the crabs appears to be correlated with the amount of cover available. / Science, Faculty of / Zoology, Department of / Graduate

Portunion conformis castrates the crab Hemigrapsus oregonensis. Piltz (1969) found P. conformis in both H. oregonensis and Hemigrapsus nudus. Kuris (1971) studied the interactions between P. conformis and H. oregonensis occurring in Bodega Bay, California. In the present study, interactions between this isopod and populations of both hosts in Tomales Bay, California, are described, including the influence of host species, sex and size on parasitic infestation and the effects of the parasites on secondary sexual characteristics of the hosts, as well as interactions between the effects of these variable.

Macome secta has been reported along the western coast of North America from the Aleution Islands to Lower California (Packard, 1918), Indicating adaptation to a wide range of habitats. In the Dillon Beach ares, Racons secta is found in a well protected cover just inside. and to the cast of the mouth of Tomales Bay. All specimens collected for this project wore takan from one site on a mudflat near Lesson's Landing, approximately one mile south of the Pacific Marine Station, Dillon Beach California. The exact location of the collection site on the mudflat may be seen in the serial photographs (Fig. 1 and 2).