by Natalya N. Ovsianico-Koulikowsky. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 121-134.

The microsporidan Pleistophora sp. is a common parasite of Crangon franciscorum, C. nigricauda, and C. stylirostris in the vicinity of Yaquina Bay, Oregon. Characteristics of the parasite are described. Skeletal muscle was the only host tissue infected. The seasonal prevalence and intensity of the parasite in crangonids are described, based on examination of 1,556 C. franciscorum, 3,877 C. nigricauda, and 1,674 C. stylirostris collected at monthly intervals from June, 1975, through June, 1976. Prevalence in C. franciscorum and C. stylirostris increased through the fall and reached winter peaks of 30.3% and 41.0% respectively, then decreased in the spring. Prevalence in C. nigricauda remained below 8% through the year. Intensity increased with size of the shrimp in the three species. Infection experiments and field observations indicate that only very young shrimp are susceptible to infection during a relatively short period during the summer months. Following initial exposure, the infection spread within the host, indicating repeated schizogonic cycles. Parasitic castration was indicated by the absence of gravid infected female shrimp and was confirmed by histological examination. Ovaries of infected shrimp did not develop beyond a very early stage. A shift in sex ratio toward females in infected shrimp also indicates that the parasite may influence sex determination. Shrimp showed little cellular response to infection. Only rarely in heavily infected shrimp was encapsulation of the parasite cysts observed, and necrotic tissue was occasionally observed. Infected shrimp succumbed before uninfected shrimp under low oxygen stress. The collection of unusually large infected shrimp indicates that these shrimp either experienced accelerated growth or lived longer than uninfected shrimp. / Graduation date: 1977

Thesis--Leyden. / "Proefschrift verschijnt met geheel overeenkomstige pagineering in Temminckia, deel VII." Author's autograph presentation copy. "Stellingen:" 3 p. inserted. Includes bibliographical references (p. 151-174).

No description available.

Typescript. / Bibliography: leaves 224-227. / xii, 227 leaves ill

Thesis (M.S.)--University of Akron, Dept. of Biology, 2006. / "December, 2006." Title from electronic thesis title page (viewed 12/31/2008) Advisor, Stephen C. Weeks; Committee members, Francisco B.-G. Moore, R. Joel Duff; Department Chair, Bruce Cushing; Dean of the College, Ronald F. Levant; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 177-196).

Estuarine ecology in South Africa has progressed in two distinct stages. The first of these was a necessary descriptive phase which documented the general distribution of estuarine animals and recorded the physical conditions within estuaries . This phase has been carried out by the Zoology Department of the University of Cape Town which has made a series of ecological surveys of southern African estuaries. These surveys have provided a vast amount of valuable information which was utilised by Day (1964.) to state some general conclusions about estuarine faunas. The most important of these conclusions is that most of the estuarine fauna is really a quiet water fauna which also occurs in sheltered non-estuarine water. The information gained in this first stage is necessarily general and it can only indicate overall trends or reveal major features of distribution. Further estuary surveys are not justified unless they deal with unique conditions. It is at this point that the second phase of estuarine ecology becomes necessary. This phase involves a detailed investigation of individual species or particular problems. The present investigation falls into this second stage of estuarine ecology and was designed to extend our knowledge of the anomuran mud prawn Upogebia africana (Ortmann). The general estuarine surveys have shown that U. africana is a common inhabitant of many estuaries and sheltered bays along the southern African coast from Langebaan on the West coast to Inhambane on the East coast. However these surveys only revealed and could not explain anomalies in its distribution such as its apparent absence from closed estuaries and from estuaries in the tropics. In addition it was not even certain whether this abundant and widespread animal should really be considered a valid species distinct from a common West Coast prawn Upogebia capensis (Krauss). It was felt that a study of an estuarine species should be based upon a sound knowledge of its distribution, population structure and habitat. Knowledge of the habitat must be gained by studies in the field to establish which facets of the environment are of importance to the species. It was decided on the basis of field observations that temperature and salinity are of prime importance: in limiting the distribution of U. africana and a detailed laboratory study was therefore made of the tolerance of U. africana to these two physical factors. The results of laboratory experiments together with field observations were finally used to interpret the ecology of the species. Most of present day knowledge of crustacean ecology has been gained from a study of European and North American animals and information about southern hemisphere species has lagged behind. It is hoped that the present study will contribute to a wider understanding of Crustacea and that it will lead to further more advanced research on South African marine and estuarine animals

No description available.

published_or_final_version / abstract / toc / Zoology / Master / Master of Philosophy