Estuaries in South Africa are important nursery areas for the juveniles of many fish species. The condition of many of these systems has, however, deteriorated as a result of degradation caused by urban, industrial and agricultural development. An assessment of the role of harbours, particularly in KwaZulu Natal, as nursery grounds has therefore become an important issue. Durban Bay has undergone considerable changes since the mid-1800s and further developments are proposed. If these developments continue, they will result in the loss of large areas of the sandbanks, but Portnet has recognised the need to integrate environmental considerations into future port developments and operations. It was the overall aim of this study to establish the nature of the association of the juveniles of four common fish species viz. Pomadasys commersonnii, Gerres filamentosus, Liza dumerilii and Leiognathus equula with these sandbanks and, thereby assess the impact of their removal. It was found that all species were abundant on the sandbanks and that the diets of P. commersonnii, G. fiiamentosus and L. equuia were very similar, consisting primarily of bivalve siphon tips, benthic crustaceans and polychaetes. The respective contributions of each food type to the diet varied with species. The diet of L. dumerilii differed from that of the other three species, consisting primarily of benthic floc, foraminiferans, ostracods and sponge spicules. Despite differences in selectivity, it was concluded, from studies of the benthos in the harbour, that all four species, irrespective of size, were feeding on these sandbanks, as opposed to in the channels, throughout the year. Removal of the sandbanks for the construction of a new pier would, thus, result in the elimination of important feeding grounds for the juveniles of these four species. / Thesis (M.Sc.)-University of Natal, 1994.

Differences in coral reef fish assemblages were investigated on six South African and one southern Mozambican reef under varying management regimes. All of the South African reefs fall within marine protected areas (MPA) but are zoned for differing types and intensities of human activity. Reefs where no human activities are allowed were termed Sanctuaries, while those on which restricted fishing and SCUBA diving are permitted were termed Protected. The reef in southern Mozambique is subjected to unrestricted fishing and SCUBA diving and was consequently termed Open. This study consists of two parts. The first dealt with a community assessment which investigated and provided baseline data on the trophic structure, density, and species diversity of fish assemblages on each of the seven study reefs. The objective was to compare the aforementioned metrics between reefs and thereafter compare them between the different protection zones. The second part of this study focused on assessing the impacts of human activities using 25 fish indicator species. These species were selected a priori based on their ecological importance and sensitivity to human activity (fishing and diving). The selection process was then guided by the results of the community assessment. The objective was to use these species as indicators of recreational diving and fishing pressure in the different protection zones. Density, biomass and size frequency analyses comprised the primary metrics in this assessment. Randomly stratified underwater visual censuses (UVC) were used to collect the fish data and these were conducted on reefs inhabited by a coral community considered to be the core community on South Africa’s reefs in terms of biodiversity and coral cover. The fish community assessment consisted of timed counts in which all non-cryptic fish species were quantified. Indicator species counts employed the point count technique with a radius of 10 m. An average of 11 community counts and an average of 62 point counts were conducted per reef. Various environmental variables and habitat characteritics were recorded during the UVCs. Multivariate analysis of the fish assemblages indicated that the fish community structure differed significantly according to reef protection status. Sanctuary reefs were significantly different from the Open reef in Southern Mozambique. Mean fish abundance was highest on Sanctuary reefs and lowest on the Open reef. In terms of overall species diversity, a total of 284 species belonging to 50 families were recorded, this being comparable to other reefs in the WIO region. Six families contributed more than 50% towards the fish community composition: Labridae, Acanthuridae, Chaetodontidae, Lutjanidae, Pomacentridae and Serranidae. All predator categories were well represented on Sanctuary reefs, while top-level predators were scarce on the High-Diving and the Open reef. Generalised linear model (GLM) regression analysis indicated that human activities were significant variables in accounting for the variance in fish community structure. The total fish abundance and biomass of the selected indicator species were significantly higher in Sanctuary zones and lowest in the Open zone. In addition, Sanctuary zones were characterised by high numbers of large predators, while non-Sanctuary zones were characterised by higher abundances of prey species. Target species were also larger and more abundant in Sanctuary zones. The data revealed that recreational fishing and high diving intensity may be influencing the fish community structure on southern African coral reefs, which was confirmed by GLM regression analysis. Long-term monitoring of these fish communities is recommended to confirm the trends observed in this data set. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

The scalloped spiny lobster, Panulirus homarus has a subspecies trio that are widely distributed in shallow-water habitats in the South West Indian Ocean. Subspecies are defined by differences in colour and abdominal sculptural pattern. A red variety with the megasculptural carapace pattern, P. h. rubellus is distributed along the south east coast of Africa and Madagascar, where they are endemic. Along the African coast P. h. rubellus stocks traverse political boundaries, Mozambique and South Africa. This project aimed to facilitate regional fisheries management of shared stocks by employing genetic tools to determine whether stocks (or populations) are indeed shared between countries. Lobster samples were collected from seven localities throughout the east African coast. The mitochondrial cyctochrome c oxidase subunit 1 region was sequenced to assess the genetic diversity 1) between different subspecies, P. h. homarus and P. h. rubellus and 2) between populations of P. h. rubellus across its African distribution range. Using DNA barcoding methods, genetic diversity was also found between morphologically distinct subspecies, Panulirus homarus homarus and P. h. rubellus which differed genetically by ca. 2-3% in sequence divergence. Both subspecies were monophyletic relative to the out-group taxa and formed well supported sister clades (BI: 1.00, ML: 93%, P: 100%, NJ: 100%). The distribution of P. h. rubellus along the African coast occurs adjacent to different current regimes and therefore varied larval transport modes (i.e. Agulhas Current and inshore countercurrents along the Eastern Cape). This may have driven the formation of subpopulations (ΦPT = 0.104, p = 0.010) which differ by ca. 1.7% in sequence difference. The pattern of gene flow of populations of P. h. rubellus lends support to the Agulhas Current being a major mode of larval transport as well as corroborates previous abundance and distribution records. Time since population expansion estimates for the P. h. homarus and P. h. rubellus subspecies as well as for the P. h. rubellus subpopulations dated back to the mid-Holocene Epoch in accordance with a warmer, more stable marine environment. Genetically distinct subspecies of P. homarus as well as differentiated subpopulations of P. h. rubellus calls for a re-visit of the current collective management of P. homarus as well as P. h. rubellus as a single genetic stock along the south east African coast. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.

This study provides information on the biology, stock status and the management of C. puniceus, a key linefish resource in southern Mozambique. This is regionally endemic to Mozambique and KwaZulu-Natal. Fairly resident species, is found on the continental shelf ranging north to Zavora and south to KwaZulu-Natal and Transkei, and inhabits rocky seabeds, ranging between 20 and l00m. In Mozambique is manly exploited by semi-industrial fleet, and exported to South Africa. The reproductive biology, assessed through gonad somatic index as well as microscopic and macroscopic assessment, indicates that spawning extends over the spring months from August to November, peaking in September. It is a protogynous hermaphrodite, relatively slow growing and long lived species. The length-weight relationships for male and female C. puniceus show to be different, and the overall length frequency distribution shows clear difference in size between male and female C. puniceus, with male length frequency distribution restricted to the larger size classes. The monthly length frequency distribution of female C. puniceus is unimodal and peak at 300 mm FL, male shows unclear year classes. Age determination was carried out using otoliths and growth was estimated using the model developed by Punt et al (1993) for protogynous hermaphrodites reproductive styles. Validation of annuli was done by examining the outer margin of otolith, and also through mark and recapture information. Validation following the first method indicated that the opaque band is laid down twice a year, but the mark recapture results were inconsistent. This contradicts previously published information on C. puniceus, and thus; both single and double scenarios were modelled. The Von Bertalanffy growth parameters found for C. puniceus suggest relatively slow-growth, with the number of rings found from reading the sectioned otolith ranging from 2 to 18. Reproducibility of age estimates was evaluated using the average percentage error (APE) technique, and was equal to 22%. The age at full recruitment was found to be 2.5 and 5 years for bi-annual and annual banding, respectively. The analysis of the age-at-50% maturity, based on double band scenario, suggests that C. puniceus mature at 1.5 year-old, which corresponds to a mean FL of 240mm. A preliminary yield per recruit assessment revealed that at the current fishing mortality, C. puniceus fishery is moderately overfished, with the spawning biomass-per-recruit at 35.43% and 36.57%, for one and two bands, respectively, of its unexploited level. Fishing mortality was equal to 0.2 year-1 and 0.41 year-1, for single and double band, respectively. YPR analysis shows that the single band scenario is less conservative than the double band assessment, which has a bearing on the management approach. It is suggested as the preliminary management strategy a reduction of the number of boats. Indeed the average number of crew per boat, needs to be evaluated in terms of overall effort. To complement this management measures, there is a strong and urgent need to establish marine reserves in order to protect spawning stock, and also, to develop an overall linefish management plan, which will help in the management of the whole linefish resource in Mozambique. Furthermore, an age and growth study for C. puniceus over a larger geographical area needs to be done as a mean to overcome the differences between previous study and this study, once C. puniceus is being shared between the two countries (Mozambique and KwaZulu-Natal). / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Acanthopagrus berda is an estuarine-dependent fish species which is widespread in the tropical Indo-Pacific. In South Africa, it is particularly abundant in the three large northern KwaZulu-Natal estuarine systems, namely Kosi Bay, St Lucia and Richards Bay. In these systems, A. berda is harvested by a variety of methods, including traditional fish traps, gillnets and hook and line. The importance of A. berda to the different fisheries was evaluated by analysing all the available monitoring data specific to catches in these three systems. A. berda was found to be one of the five most important species taken in both the gill net and recreational fisheries at Kosi Bay and St Lucia. It was less important in the marine-dominated Richards Bay system. Catches were generally seasonal, with trends in catch per unit effort (cpue) for A. berda related to annual spawning migrations. The long-term trend in cpue for this species in the Kosi recreational fishery showed a disturbing downward trend. Ages of A. berda specimens caught in northern KwaZulu-Natal estuaries were determined by examining whole otoliths. Age estimates were validated by marginal zone analysis and oxytetracycline labelling, which indicated that opaque deposition occurs primarily from September to November each year. The reproducibility of age estimates was described by a coefficient of variation of 10%. The special von Bertalanffy growth curve was found to best describe the growth of A. berda. The parameters of the von Bertalanffy growth curve indicated that A. berda in northern KwaZulu-Natal is slow growing, attaining at least 16 years of age. The age and growth parameters and mortality estimates from catch curves were used to complete a per-recruit stock assessment of the species. The results of the spawning biomass per-recruit model using different ages of first capture indicate that A. berda is at 47% to 55% of its unfished level. Although these results may indicate that A. berda in northern KwaZulu-Natal is not at present overexploited, longevity coupled with late maturation, sex change, estuarine dependency, increasing catches of A. berda and poor monitoring give cause for concern for the continued sustainable use of this species in northern KwaZulu-Natal. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Coral reefs are being destroyed and degraded by natural and anthropogenic processes. Live corals are becoming increasingly popular as marine aquarium specimens, in both the commercial and private sectors, leading to the degradation of coral reefs. This often has serious economic implications for the fishing, aquarium and tourist industries. It is clear that there is a need for the management and protection of these fragile ecosystems. The artificial propagation of coral is desirable as it will alleviate the demand for wild coral specimens, and will also provide a stock for the rehabilitation of damaged reefs. Although corals are being propagated worldwide by hobbyists, reports on their work are mainly anecdotal and there is little in the scientific literature on the specific requirements for optimal growth rates and survival in suitable coral species. This study thus focused on developing techniques to propagate a range of appropriate coral species and to promote their optimal growth. The results revealed that different morphological groups of scleractinian corals require specialised techniques of fragmentation and attachment to ensure survival. The corals were broken using a hammer and chisel. Attachment techniques varied from the use of superglue (which is widely used in the United States), to thermoplastic glue. The mean mortality using superglue was 73% (n=120, ±0.167), using epoxy, 62% (n=120, ±0.127) and with thermoplastic glue it was 11% (n=120, ±0.108) Superglue was extremely difficult to work with and proved ineffective, especially when attempting to glue uneven surfaces. Certain species did not survive using this adhesive due to exposure of the coral to air. The most effective method of rapid attachment was the use of thermoplastic glue that set rapidly underwater. The use of electrolysis to promote the attachment of coral nubbins was tested as an alternative to the various adhesives. This method increased the survival of the nubbins and eliminated exposure to air. It has proven suitable for both coral propagation and in situ reef rehabilitation. Growth experiments revealed that the manipulation of current flow, light and the addition of different feeds had different effects on the growth rates of selected candidate species. A suite of optima was thus developed for each species. The majority of species grew best in a bi-directional current flow, with yeast as feed, under actinic blue light. An experiment that combined the optimal current flow, feed and light conditions, revealed that the majority of species grew best under mixed light with yeast as feed. The trade in corals is sensitive in terms of their handling, transportation and CITES (Convention on International Trade in Endangered Species) status. Having established the viability of their propagation, consideration was given to appropriate regulatory and marketing procedures to accommodate this sensitivity of the cultivated material. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

This study provides information on the age and growth of two important Iinefish species, Scomberomorus pluriline~tus and Polysteganus undulosus. Age determination for both species was carried out using otoliths and growth was modelled using age- and length-based methods. For the age-based method various growth models were evaluated to determine which growth function best described the age-length data, whilst Shepherd's Length Composition Analysis was used to estimate growth parameters from length-frequency data. Preliminary stock assessments, based on limited catch data, were also attempted for both species. Age estimates for the pelagic migrant S. plurilineatus, derived from reading whole otoliths, ranged from 0 + to 6 + years. As validation by marginal increment analysis was inconclusive because of the seasonal occurrence of this species in KwaZulu-Natal waters, it was assumed that a single opaque band was laid down in the otolith annually. Reproducibility of age estimates evaluated using the average percentage error (APE) technique was good (9.4%). Von Bertalanffy growth parameters were poorly estimated from length-frequency data because multiple maxima were encountered on the fitting surface. However, from the age-length data, growth was adequately modelled by the von Bertalanffy growth equation: L t =9 3 5mmFL (l-e -0. 583yr-1 (t+o. 991yr) ) S. p!urilineatus are fully recruited to the fishery at the age of 1 + year and the ageiv at-50% maturity is 2 + years. Preliminary per-recruit analyses indicated that the spawner biomass of S. plurilineatus is at 50% of its unfished level. Polysteganus undulosus is an endemic, reef-dwelling sparid and large catches weremade earlier in the century. Age determination was carried out using sectioned otoliths collected in 1962 and 1963 before the collapse of the fishery. Age estimates ranged from 3 + to 20 + years. Marginal increment analysis indicated that active deposition of opaque bands occurred during winter but, because of the seasonal occurrence of P. undulosus in KwaZulu-Natal, validation was inconclusive. Reproducibility of the age estimates was low (APE = 18.2%) because of difficulties with band interpretation as a result of stacking on otolith margins in old fish. Von Bertalanffy growth parameters could not be adequately estimated from length frequency data because of the slow growth and longevity of this species. However, from the age-length data, no difference in growth rate between the sexes was observed, and growth for the combined sexes is described by the following logistic equation: L = 942mmTL t 1+e-O.277yr-l(t-S.178yrs) The age at full recruitment was found to be 12 + years and the age-at-50% maturity was 8.8 years. A preliminary stock assessment revealed that the spawner biomass of P. undulosus was already at 25% of its unfished level in the early 1960s. / Thesis (M.Sc.)-University of Natal, 1996.

Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Fishing, and artisanal fishing in particular, plays a key role in the provision of rural employment and more importantly, household food security in the developing nations. The importance of artisanal fishery is shown in Malawi where artisanal fishery produces between 85-95% of the total fish production, and about 70% of the animal protein in human consumption comes from fish. About 43,000 people are employed directly in artisanal fisheries and approximately 100,000150,000 are indirectly employed within the artisanal fishery. Owing to increasing human population in the developing countries coupled with the common property, open-access nature of the fish resource, the resource has not been able to cope with the ever-increasing socio-economic demand placed on it. The resource is so degraded that it is has started to decline beyond capacity to sustain itself. This study was an attempt to examine and understand the artisanal fishery as it contributes to the socio-economic well being of the rural population particularly, the enclave communities of Lake Malawi National Park. The present study used structured interviews, focus group interviews, key informant interviews and personal observation to collect socio-economic information of the fishery. These research tools revealed that among the enclave communities income levels are low and unsustainable due to declining productivity of fishing. The decline may be a result of increasing human population, weak community-based institutions, limited agriculture, poor infrastructure with regard to processing and marketing of fish, limited supplementary and alternatives economic activities, and the fishing methods. Documentary information was used to contextualize artisanal fishery, to examine and understand the common-property and open-access nature of the fish resource as it relates to the exploitation Of fish among the enclave communities. Integrated development that brings together conservation and socio-economic development is the only option that will increase the income of the enclave communities to sustainable levels and achieve the Park's conservation objectives. The socio-economic intervention options should include provision of basic social facilities such as education, health, safe water etc, increase the economic power of the enclave communities through irrigation, adding more value to the fishery, engaging in aquarium trade, community-based eco-tourism and beekeeping. These options would lead to socio-economic sustainability among the enclave communities and would bring about the conservation objectives of the Park. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

The KwaZulu-Natal Bight is influenced by various nutrient inputs from the Thukela River and particular oceanographic features of the shelf such as the St Lucia upwelling cell and the Durban lee eddy that are in turn associated with Agulhas Current behaviour. Little is known about KZN Bight community dynamics of most faunal groups and so knowledge about the ecological functioning of this system as a whole is lacking. To address this, a large multidisciplinary project on the Bight was conducted through the African Coelacanth Ecosystem Programme. One aim of the programme was to establish whether nutrient inputs have significant impacts on this oligotrophic shelf and if so, how? This study looked at the macrobenthic compartment to examine variations in diversity across the KZN Bight in the midshelf habitat only. Changes in diversity were explained in relation to important habitat and/or process drivers. Replicated biological and sediment samples were collected in and between the three focus areas of high nutrient input along the Bight spanning an area from Durban to just south of the St Lucia Estuary mouth. Samples were collected twice at the same stations, once during a wet period (February 2010) and once during a dry period (August 2010). These periods were selected to represent high and low outflow and thus potentially higher and lower nutrient inputs to the Bight, respectively. Macrobenthos collected by 0.2m2 Van Veen grab were identified to the lowest possible taxonomic level and resulting data were analysed using combinations of univariate and multivariate statistical procedures. Diversity was described using well-published techniques that related to community Alpha () and Beta (β) diversity and including several newer methods such as Taxonomic Diversity indices (Taxonomic Distinctness (Δ*), Average Taxonomic Distinctness (Δ+), Variation in Taxonomic Distinctness (Λ+)) to determine the taxonomic relatedness of macrobenthic communities within the study area. Midshelf macrobenthic community  and β diversity was highly variable across the shelf with no distinct patterns related to focus area. Diversity values were however similar to values obtained in what are considered highly diverse tropical and high latitude shelves. Diversity was then related to hydrographic parameters measured on the Bight to understand the possible indirect or direct roles the Agulhas Current and Thukela River have in maintaining the macrobenthos. Findings were that diversity was only weakly related to measured environmental variables suggesting far more complex interactions in the biophysical environment of the Bight. This was highlighted by the finding that alpha and beta diversity measures had complimentary relationships as an inverse trend was found between these measures along the KZN Bight. Thus, more detailed systematic studies on the Bight are needed to fully understand the role and supply of nutrients on specific communities and how these pertain to the ecological function of the whole shelf ecosystem. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.