The eelpouts, Zoarcidae, are a group of bony fishes, most species of which inhabit continental shelves and slopes of boreal seas. There are about 200 species of eelpouts, most of which are rare in collections, thus they have been only cursorially studied by most workers. as a result, the systematics of the family is in a poor state. This work is a contribution to the improvement of that state. The anatomy of all nominal genera of Zoarcidae was studied in an attempt to reconstruct phylogeny and establish the limits of genera. From analysis of a matrix of 63 characters, the 43 nominal genera recognized here form two subfamilies. One, Lycozoarcinae, contains only the primitive Lycozoarces regani. The other, Zoarcinae, is divided into three tribes, Zoarcini, Gymnelini and Lycodini. The more primitive zoarcids are characterized by having 4-6 suborbital bones arranged in a circular pattern close to the orbit, and complete cephalic lateralis pore patterns, except some of the few deep-sea forms. The more derived zoarcids are characterized by the loss of the interorbital pore (except for a few reversals) and by having 6-11 suborbital bones arranged in an "L-shaped" pattern away from the orbit (except a few which have lost some bones). An hypothesis is presented for the sister group relationship of Zoarcidae with six zoarceoid families: Ptilichthyidae, Zaproridae, Anarhichantidae, Stichaeidae, Pholididae and Scytalinidae. Bathymasteridae is hypothesized to be the primitive sister group of all the above taxa. The zoarceoids are probably most closely related to notothenioids and some of the trachinoids than to blennioids, a group recently restricted to six tropical-subtropical families. Since fully 45% of the genera recognized here are known from less than 15 specimens each, zoogeographic patterns are unsatisfactorily resolved. Considering the known distributions of all zoarcid genera, the highest endemism is found in temperate South America (30%), the northwestern Pacific (23%) and northeastern Pacific (11%). The best known deep-sea genera and species are wide-ranging, this perhaps due to the benthic, precocious larvae of most species.

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Bibliography: leaves 188-199. / Previous sandy beach research described beach macrofaunal communities according to the swash exclusion hypothesis (SEH). This hypothesis stated that more species are present on fine grained, flat dissipative beaches due to a more benign swash climate. It suggested that, as beach morphodynamics change to reflective conditions, which is experienced on coarse, steep beaches, few species can survive; these beaches are therefore characterised by lower macrofaunal diversities, abundance and biomass. Furthermore, little proof has been obtained of biological interactions such as competition or predation, and beaches have been described as physically controlled environments. The aim of this investigation was therefore to redifine the SEH in more specific terms, preferably into a form that is experimentally testable, and to find evidence of biological interactions that could be important enough to modify/explain population or community structures. Furthermore, the study aimed to find experimental procedures to serve as alternatives to the previously correlative type approach.

Bibliography: leaves 128-133. / This thesis makses an analysis of survey data of horse mackerel catch per unit effort and acoustics data from R/V Dr. Fridtjof Nansen over twelve years in the region of the Angola-Benguela front. The main objectives are: to characterize the pattern of distribution and mixture of Cunene and Cape horse mackerel in the area around the Angola-Benguela front and to study the relationships between the distribution of T. capensis and T. trecae and the movements of the Angola-Benguela front. The role of sea surface temperature (SST) was also examined, assuming that this environmental parameter would be related to the seasonal variation in distribution of both species of horse mackerel, at least in the overlap area.

Bibliography: leaves 69-81. / This thesis reports on an investigation into some aspects affecting and contributing to the flow of organic matter through a subtidal reef environment. In particular, the contribution of Porifera to the organic matter pool in terms of biomass and the consumption of organic matter by a dominant Porifera species are assessed. Further, reef fauna biomass and community structure, as well as Porifera respiration, the subsurface temperature regime above the subtidal reef and the amount of organic matter available for utilization are examined.

Includes bibliographical references. / Despite the importance of movement ecology studies, the field faces a prevailing challenge of methodological limitations in tracking individual organisms. This research investigated the utility of the stable isotope technique to trace movements of ducks in southern Africa. I sampled and analysed feathers of ten duck species for stable isotope proportions of Carbon (δ13C), Nitrogen (δ15N) and Hydrogen (δD), from five wetlands (Strandfontein and Barberspan in South Africa, the Manyame catchment in Zimbabwe, Lake Chuali in Mozambique, and Lake Ngami in Botswana) as test cases.Sampling was carried out at different seasons to account for seasonal isotope signature variations. Isotope signatures of feathers grown at different moulting locations were compared to test whether southern Africa shows stable isotope spatial patterns (distinct isotopic regions). Feathers grown at different life-phases were compared to test whether different sites had been used and if more mobile species showed more and stronger isotope distinctions. Finally, growing flight feathers grown at moulting locations were compared across species to query how much information on diet and foraging behaviour can be inferred from southern African duck feather stable isotopes.Feather isotope signatures were distinct by site in at least one of the tested isotopes, for the majority of ducks tested. Strandfontein had more and stronger distinctions of isotope signatures between feathers grown at different life phases. This site is the closest to the sea and most likely to have marine-influenced isotope signatures especially in δ15N, it falls within the Mediterranean climatic conditions experiencing winter rainfall unlike all the other sites. Vegetation compositions (C3 and C4 plant distributions) therefore vary across sites influencing δ13C patterns. More mobile species (only Egyptian Goose Alopochen aegyptiacus from Strandfontein, and Cape Shoveler Anas smithii from Barberspan; determined by mobility scores from other studies) had more and stronger distinctions between flight and body feathers. All the other species did not comply with mobility scores. They showed weaker and fewer tissue signature distinctions than their mobility scores suggested. There were high isotopic signature overlaps in δ13C and δ15N across and within feeding guilds at each moulting site implying dietary overlaps during moulting. More overlaps occurred during the dry seasons (summer in Strandfontein and winter in Lake Chuali, Manyame catchment site, and Lake Ngami). Higher isotopic variances (higher dietary flexibility) were associated with isotope signature divergence to mobility scores especially in Cape Teals and Yellow-billed Ducks.The isotope technique is flawed with uncontrollable sources of variation which potentially confound movement inferences. It is best used when accompanied by conventional methods to detect and counter against species specific biology and dietary behaviour imposed biases in tissue isotope signatures. Further research on how species specific biological processes affect the reflection of spatial patterns of isotopes in feathers is recommended. Multi-isotope time explicit approaches and trace element analysis were also recommended. Scientists should be wary about basing management strategies or building theory about movement patterns of species based on the technique at least in stochastic environments such as southern Africa. My results provide empirical evidence that the technique is unreliable at this scale of analysis. In particular, the majority of ducks in this region are not good candidates for use of isotopic signatures in distinguishing movement patterns of southern African ducks.4983

Includes bibliographical references. / All free-living animal species have their own unique parasite assemblages. These parasites can have a significant impact on the fitness and ecology of their hosts, and through them the ecological systems in which they occur. Gaining knowledge about these parasites offers important information on the biology, systematics and phylogenies of their hosts. During this study the following were collected: flea, fly, mite, tick and helminth species from 96 Natal Long-Fingered bat (Miniopterus natalensis Smith, 1834) individuals sampled from seven localities across South Africa. This study aimed to both identify the species forming part of this parasite assemblage, and attempted to explain the distribution of the parasites and the factors influencing it.

Bibliography: leaves 69-74. / Greater Flamingos, Phoenicopterus ruber, were excluded from intertidal areas of two lagoons and subtidal areas of one of these on the Namibian coastline. Macrofaunal and meiofaunal numbers increased at all exclusion sites, but taxon-specific responses were variable. Both intertidal sites were polychaete dominated; subtidally amphipods formed dense tube mats that covered the substrate. All except one macrofaunal species showed significant response to caging. Relative to controls, macrofaunal numbers increased approximately three times inside subtidal exclosures, and one and a half times intertidally, but diversity indices were similar between treatments. There was some evidence that amensalistic interactions developed between macrofauna within exclosures. Intertidally at Walvis Bay rneiofauna showed little response to flamingo exclusion, but subtidally all groups showed statistically significant responses to treatments. At Sandwich Harbour, foraminifera and ostracod abundance changed significantly. Bacterial counts were lower in exclusions at all sites, but significantly so only at Sandwich Harbour, which was the only site where chlorophyll concentrations did not change significantly. Sediment particle size composition was unaffected at all sites. Eh and organic content of sediments changed least subtidally; pH was affected by the treatment at both Walvis Bay sites, but not at Sandwich Harbour. Partial cages, used as cage controls, indicated that results were not artefacts caused by caging. Overall, it was clear that P. ruber was important in structuring communities in the areas studied. In the absence of P. ruber, physical disturbance may be the most important force structuring benthic communities.

This thesis is presented in three main sections. Each section is treated as a separate entity. The first deals with population structure, dynamics and production. The second reports on population respiration and the third section touches briefly on consumption. Conclusions are drawn in each section and a resume of the work concludes the thesis. This work is being followed up by other researchers tackling other populations in the system to build up a model of structure and functioning of the kelp bed community and ultimately the fate of the primary production of the kelp plants.