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<p>Beach-cast kelp (the most widely used feed for commercially grown South African abalone) is plentiful during winter months when periodic storms cause kelp to wash ashore. During summer, however, this resource is not always readily available and farmed abalone are often starved for short periods. The aim of this research was to assess how periodic kelp starvation influences growth of the commercially grown abalone, Haliotis midae Linnaeus.</p>

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No description available.

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The aim of this research was, first to test the suitability of different seaweeds and formulated feeds as food for post-weaning juvenile South African abalone and secondly, to test the effects of basket design on the growth of grow-out juvenile abalone in both flow-through and re-circulation systems.

<p>Beach-cast kelp (the most widely used feed for commercially grown South African abalone) is plentiful during winter months when periodic storms cause kelp to wash ashore. During summer, however, this resource is not always readily available and farmed abalone are often starved for short periods. The aim of this research was to assess how periodic kelp starvation influences growth of the commercially grown abalone, Haliotis midae Linnaeus.</p>

Amphipods are the most ubiquitous animals, after nematodes, on earth. Although there are several terrestrial amphipod species, most are aquatic. They are familiar animals in the water table exposed in cave environments and boreholes. The food source on which the amphipods depend was not directly observable in the cave environments frequented by the amphipods. In order to establish the role cave-dwelling amphipods play in ecology, the primary purpose of this study was thus to determine what cave-dwelling amphipods feed on. Amphipod, water and sediment samples were collected from five different caves, in the northern part of South Africa, namely Koelenhof Cave, Sterkfontein Cave, Ficus Cave, Peppercorn’s Cave, and Irene Cave. Following collection and transportation, resulting in zero amphipod mortalities, all of the samples were transferred to rectangular fish tanks stored in an environmental room, set up in such a way as to mimic the conditions in the caves as closely as possible. Long term adaptability and survival proved to be a successful undertaking, resulting in the death of only two amphipods per tank. Scanning electron microscopy was used to observe the mouthparts of the amphipods in order to begin establishing their feeding behaviour. Standard microtechniques were carried out to establish the general histological orientation and histology of the gastrointestinal tract. A Histochemical Fluorescent staining method was employed, and a reddish-orange fluorescence was observed, thereby indicating the presence of mucous in the GIT. Several feeding experiments were carried out, and it was established that on average amphipods can survive without a food source for a maximum of sixty ABSTRACT xv days. Through a series of different feeding experiments, it was determined that amphipods ingest bat faeces, leaf litter, sediment and yeast, with leaf litter producing the highest rate of survival. It was also observed that amphipods, regardless of body size, are predators, scavengers, and cannibals, which may provide an explanation as to why amphipods display evasive behaviour. Microbiology plays a vital role in determining what amphipods feed on, and therefore water, soil, and digestive contents of amphipods were studied using a wide array of microbiological analyses: Heterotrophic Plate Counts; Total Coliforms; Faecal Coliforms; Faecal Streptococci; Confirmatory test for Escherichia coli; Detection of Clostridium, Pseudomonas, and Salmonella. According to the South African Bureau of Standards, the quality of the water contained within all four of the caves in this study may not be used for human consumption prior to undergoing various purification processes. Once the role that cave-dwelling amphipods play in ecology has been firmly established it may then be possible to make use of amphipods as biological indicators, because since they inhabit cave streams and groundwater and are sensitive to pollutants, declines in their populations could indicate a decline in the water quality in their streams and surrounding groundwater supply. / Dr. J.F. Durand

Introduction : Family Poultry (FP) are birds of indigenous breeds living in almost symbiotic relationship with human communities. The chickens are usually free ranging, or have very limited restrains on their access to the village environment. African livestock population statistics for 1995 indicates poultry to be the most numerous species of farm animal (Anonymous, 1996a). More than 80% of poultry are kept in rural areas and contribute substantially to annual egg and meat production (Sonaiya, 1997). Throughout Africa poultry production stems from ancient traditional practices. FP is the most important type of poultry kept on the continent. In general, village producers keep small flocks of between 5 and 20 birds per household (Gueye, 1997a). Women and children play a key role in their management (Kitalyi, 1996). Because of its productivity, FP production has been neglected and is frequently considered by farmers as an insignificant occupation compared with other agricultural activities. Nevertheless, outside urban centers and especially in non-coastal areas, FP provides the population with a vital source of protein and income. In addition, they play an important role within the context of many social and/ or religious ceremonies. Although this type of poultry constitutes an important part of food security for rural households in South Africa, scientists have not explored this area of research for improving or recording this production system. Yet, FP survived for decades without being wiped out, in the interim, their keepers have gathered and stored a wealth of knowledge and experience, ensuring the survival of this genetic resource. The objective of this study was to collect the baseline data on FP production systems, determine their production constraints and achieve data for future use in the intervention strategies.