Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

The illegal sale of East Coast rock lobster (Panulirus homarus) along the N2 highway at Mfazazana on the south coast of KwaZulu-Natal, continues to create tension between the local community and conservation and other authority structures in the region. Panulirus homarus (P. homarus) is a valuable commodity in an area distant from industry and other economic prospects and is within easy reach of both the harvester, in terms of its intertidal living space and the market, in terms of the N2 and the economy in seafood prevalent in the region. P. homarus is therefore at risk by virtue of its biology and habitat, and the illegal nature of its capture tests the parameters of sustainable resource management still further. This research addresses the issue of sustainable resource use through an examination of the perceptions of the various stakeholders who are involved in the use and protection of P. homarus at Mfazazana. This study was commissioned by the Communications Section of the KwaZulu Department of Nature Conservation (KONC) in response to continued illegal harvesting and trade of P. homarus at Mfazazana. One of the mandates of the Communications Section is to initiate and maintain environmental education programmes and thus comply with the KONC mission statement (See Appendix 1a). Specific objectives of the study include: • how respondents perceive their relationship with, responsibility to and role in terms of P. homarus • how respondents perceive their relationship with, responsibility to and role in terms of the others involved with P. homarus • how present legislation is perceived by stakeholders • what options exist regarding the regulation and/or management of P. homarus • whether changes over time have occurred in the respondents' relationship with P. homarus Fishing and trading activities were inv~stigated using informal, loosely structured questionnaires which elicited qualitative information. Two main groups were selected. and respondents were interviewed either individually or in small groups. The crayfishers made up the first group and the resource managers made up the second group which included the Natal Parks Board (NPB), the KONG, the Hibberdene Tourism and Publicity Association, the Community Policing Forum, the Community Development Forum at Mfazazana and the South Coast Fishing Forum. The study provided an understanding and explanatiol] of how the elements of the locality interact with underlying structures and human agency in time to produce the conflict over the marine resource P. homarus at Mfazazana. It was found that the conflict between stakeholders, as a result of differing perceptions regarding the illegal harvesting of the resource, was obstructing the sustainable management of P. homarus at Mfazazana. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 102-115).

Aquatic invasive species are a major threat to native freshwater biodiversity. The North American signal crayfish Pacifastacus leniusculus was introduced to Great Britain during the 1970s and is now widely distributed throughout England, Wales and Scotland. First recorded in Scotland in 1995, P. leniusculus is now established at more than twenty sites. The only other introduced crayfish species present in Scotland is the white-clawed crayfish Austropotamobius pallipes. A. pallipes is restricted to only two locations in Scotland, Loch Croispol and Whitemoss Reservoir. P. leniusculus negatively impacts macrophytes, invertebrates and fish though ecological and physical processes. Additionally, P. leniusculus has displaced A. pallipes throughout much of its native range within Great Britain due to competition and disease. Consequently, the two A. pallipes populations in Scotland have a high conservation value. This PhD study aimed to improve understanding of P. leniusculus invasion success by examining trophic dynamics and to develop methodologies that could improve the detection and control of P. leniusculus populations in Scotland. Stable isotope analysis was used to determine the diet composition, trophic position and whether an ontogenetic dietary shift occurs in the Loch Ken population of P. leniusculus. Bayesian mixing models indicated that P. leniusculus in Loch Ken do exhibit an ontogenetic dietary shift. Additionally, individuals of all sizes occupied the trophic position of a predator in Loch Ken suggesting that invertebrates and fish constitute an important component of P. leniusculus diet. Stable isotope analysis was used once again to compare the isotopic niche width and diet composition of P. leniusculus populations from Loch Ken and A. pallipes populations from Loch Croispol and Whitemoss Reservoir. At the species level, A. pallipes exhibited a larger niche width than that of P. leniusculus. At the population level, the isotopic signatures of the A. pallipes populations were considerably different from each other suggesting an overestimation of A. pallipes’ niche width at species level. Results showed no dietary overlap between species and Bayesian mixing models suggested P. leniusculus and A. pallipes were consuming different resources, indicating there would be no direct competition for food resources if they were to co-occur. A plus-maze study was used to determine if P. leniusculus exhibited a preference for one of four food attractants (Oncorhynchus mykiss, P. leniusculus, beef or vegetation), which could be used to improve trapping efficiency. In the maze system, P. leniusculus exhibited no preference for any food attractant presented. This would suggest that either the maze was not a good model or food attractants would not improve trapping efficiency of P. leniusculus. Additionally, a comparative investigation into the use of gill nets as a method to control P. leniusculus was conducted. Results showed that the net type and the presence of fish entangled in the net influenced the number of P. leniusculus caught. Finally, environmental DNA (eDNA) was used and evaluated for detection of P. leniusculus. A robust quantitative Polymerase Chain Reaction (qPCR) assay and DNA extraction protocol were developed. Using the developed qPCR assay, P. leniusculus eDNA was detected in controlled aquaria conditions but not in environmental water samples collected from the field. Furthermore, the quantities of P. leniusculus eDNA declined in aquaria conditions while individuals were still present suggesting the mechanisms for eDNA release by P. leniusculus are complex. Stable isotope analysis indicates that P. leniusculus exhibit an ontogenetic dietary shift, and in each life stage, P. leniusculus function as an omnivore but occupy the trophic position of a predator. Niche width analysis revealed that the diet of P. leniusculus was less general than that observed in A. pallipes and thus diet of P. leniusculus may not be responsible for invasive success. Food attractants will not enhance trapping efficiency but nets may present a potential new method to control P. leniusculus. Similarly, eDNA presents a promising new method for rapid detection of P. leniusculus. It will not be possible to eradicate P. leniusculus in Scotland but the findings of this PhD may help prevent establishment of new populations. These results should be incorporated into future management strategies for P. leniusculus populations in Scotland and may have broader applications in Great Britain and Europe.