Fisheries in African reservoirs are typically multi -species and in most cases the fish resource is harvested with a number of gears. These characteristics complicate their management and the development of management procedures. Typically, long time series of data on catch and effort and length- or age-based catch are not available for these fisheries. This precludes the use of data intensive methods such as multi-species virtual population analysis. The principal aim of this thesis was to develop a management procedure for African reservoir fisheries that takes into account the pertinent biological characteristics of the target species and accounts for the multi-species and multi-gear irIteractions in such fisheries. An opportunity availed itself to undertake this work on Lake ChicaIllba (19°08'S 33°08'E) a man-made hydroelectric dam in subtropical Mozambique (Manica province). The specific objectives of this study were: to obtain locality specific biological parameters for the target species in Lake ChicaIllba; to assess gear utilisation trends in the fishery through the determination of gear-selectivity, catch rate and effort for each of the principal gears used in the fishery; to assess the fishery using traditional per-recruit models and to test existing and new per-recruit models that account for the multi-species and multi-gear nature of the fishery and to determine the adequacy of each of these approaches in the determination of suitable target reference point (TRP) exploitation rates. The three principal specIes in Lake Chicamba are the introduced largemouth bass, Micropterus salmoides, and two cichlids the Mozambique tilapia, Oreochromis mossambicus and the redbreast tilapia, Tilapia rendalli. Sectioned otoliths were used for age and growth determination. Marginal zone analysis showed that annulus formation in all three species occurred during winter. The maximum-recorded age was 5 years for M. salmoides, 16 years for T. rendalli and 10 years for O. mossambicus. Growth of the three species was best described by the 3 parameter von Bertalanffy growth model as ℓa = 465.51 (1 - e⁻ₑ·ₑ⁷⁵⁽a⁺⁰·⁰⁰⁹⁾ mm FL for M salmoides; ℓa = 238.74 (1 - e⁻⁰⁶³⁶⁽a⁺⁰·⁹⁰⁵⁾) mm TL for T. rendalli; and ℓa = 266.06 (1 - e⁻⁰⁷⁹⁰⁴⁽a⁺⁰·²⁶⁹⁾) mm TL for 0. mossambicus. Female T. rendalli attained 50%-maturity at 2.89 years, while O. mossambicus matured at 2.83 years and M. salmoides at 0.9 years. Both cichlid species spawned throughout summer while M. salmoides had a very short spawning season from August to September. The total annual mortality rate (Z) for M. salmoides in Lake Chicamba was 1.27 yr⁻¹, the mean empirical estimate of natural mortality (M) was 0.73 yr⁻¹, and fishing mortality (F) was calculated at 0.54 yr⁻¹. For T. rendalli Z = 0.31 yr⁻¹, M = 0.20 yr⁻¹, F = 0.11 yr⁻¹ and for 0. mossambicus Z= 0.62 yr⁻¹, M= 0.38 yr⁻¹, F= 0.24 yr⁻¹. The three species exhibited reproductive traits, which implied a high reliance of recruitment on spawner stock (nest guarding in T. rendalli and M. salmoides and mouthbrooding in O. mossambicus). For this reason it was decided that the cichlid fisheries should be managed using TRPs which maintained the spawner biomass-per-recruit at 50% (FSB50) of pristine levels. However, based on good evidence it was hypothesised that the high rate of fishing mortality helped to maintain the fast growth rate of M. salmoides. It was, therefore, decided to manage this species at a TRP of F SB40. The three most important fishing sectors were the gill-net, seine-net and hook-and-line fisheries. The total catch for 1996 was 223 t. The gill nets selected all three species at a size/age approximating 50%-maturity while the seine-net and hook-and-line fisheries selected mainly juvenile fishes. There was strong evidence to suggest that seine net fishing also disrupted spawning. It was shown that the 'traditional' single-species per-recruit models were unsuitable to assess multi-species and multi-gear reservoir fisheries. Since existing multi-species/multifishery yield-per-recruit models were not capable of defining FsB(x) TRPs, a new multispecies/ multi-fishery spawner-biomass-per-recruit approach was developed. This approach allowed for the simulation of the response of spawner biomass-per-recruit to changes in effort in the three fishery sectors, simultaneously. The models showed that the spawner biomass-per-recruit, at current effort levels, was higher than the suggested TRP for the three species. However, it was shown that an increase of 10% in current total effort would reduce spawner biomass-per-recruit to below the recommended TRP levels. With the closure of the seine-net fishery, gill-net effort could be increased to 338 fishers (340 for management purposes) and effort in the hook-and-line fishery could be increased by 30% before the TRP was reached. To maintain the fish stocks above TRP levels, effort control was considered to be the most effective management method. The main recommendations for Lake Chicamba were to close the seine-net fishery, to limit the gill-net fishery to 340 fishers (using 137-m long x 3-m deep gill nets) and to maintain the open access nature of the hook-and-line fishery. The multi-species/multi-fishery per-recruit approach allows for the meaningful simulation of various scenarios and provides relatively robust management options. In the absence of long time series of effort and age- or length-based catch data, this approach was considered as the most suitable assessment method for multi-species/multi-gear African reservoir fisheries.

Indigenous knowledge use in identifying artisanal fishing zones is the core issue in this dissertation. It seeks, on one hand, to show the potentially of this knowledge and to establish the relationships between indigenous and scientific knowledge in fishing zones identification and, on other the hand, it is also a trend for alleviating those fishing zones surrounding beaches, estuaries and bays highly exploited by artisanal fishermen. Pushing artisanal fishermen upward offshore and/or into the open sea, they will fish more quality and high economic value fish contributing to enhance their income. By so doing, artisanal fishermen will uplift their living standard and, at the same time, they will contribute to sustainable artisanal fisheries management. Angoche District in Nampula province, north of Mozambique is the study area. The study was carried out to describe the logical sequence underlying on the process of identifying artisanal fishing zones using indigenous knowledge. The relationship between indigenous and scientific knowledge is treated with particular attention. The nature of the study is descriptive and analytical based on qualitative and quantitative data. The method used for data collection was face-to-face interviews using structured and semi-structured open-ended questions. Data on socioeconomic, traditional and cultural practices, technological and climate characteristics were collected, analyzed and discussed. Factors underlying artisanal fishing zones were studied. Spatial and non-spatial information for artisanal fishing zones identification was recorded applying Global Positioning Systems (GPS) and, later, processed and analyzed employing Geographical Information Systems (GIS). Finally, a map showing the localization and distribution of the identified fishing zones in the study area was produced. Results from the research show that identification of fishing zones offshore or open sea can be done simply based on local indigenous knowledge. The GIS technology employment facilitates the inclusion of indigenous knowledge into other knowledge which can be used for local decision making. Sustainable fisheries management can only be achieved by developing a science based on the priorities of local people, and creating a technological base that includes both traditional and modern approaches to problem-solving. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Sound management of information and data is an essential cornerstone for efficient and effective decision making. Structured, up to date and easily retrievable data from several heterogeneous sources is often required to effectively manage, monitor and predict resource quantities particularly for depleting resources such as fish. The documentation and management of fisheries data in most developing countries however poses great challenges. The main aim of this study therefore is to design an information system (IS) for Artisanal Fisheries management. The developed IS is supported by a database. Secondary data, from the provincial offices of Moma and Angoche in Mozambique, is used to test and populate the prototype database. The manner in which the database is developed demonstrates how in practice a database can be created as part of an information system. However, due to time restrictions, a complete database for the AF system could not be developed. To accomplish the objectives of the study, a model of the Artisanal Fisheries (AF) system was developed first. Based on standard system development approaches, the key components of the AF system that include; processes, data flows and data stores, were identified. The developed conceptual system was then used to identify critical data stores for the AF system and data models were subsequently developed. A prototype database to support the AF system was then implemented in MS Access. The motivation for this study is as a result of two observations made on information management which are a challenge in artisanal fisheries management in Moma-Angoche. These observations are; (i) the current information system lacks a structured approach and a database to document and archive data/information on the artisanal fisheries subsector; and, (ii) the high proportion of the data/information collected from different sources is not well processed, analyzed and is not user-friendly as yet. The Moma-Angoche Provincial Fisheries office was chosen because it is strategically suitable for research. This has been demonstrated by the amount of socio-economic artisanal fishing census data already collected and by the research on stock marine resources already carried out. As a result, the study area has become a pilot zone of integrated fisheries development projects. During the life cycle of the various projects, and even after their termination, the area remained an important zone where subsequent studies (for example baseline studies) were carried out. Furthermore, the existence of subsequent data available from those studies allows a good opportunity for data comparisons to be made. / Thesis (M.Env.Dev.) - University of KwaZulu-Natal, Pietermaritzburg, 2007.