Catch trends from Lake Victoria - Tanzanian waters

Catch trends from Fisheries Department reports from the last eleven years (1985-1995) were analyzed. These showed a shift in the fishery from a cichlid-based system to one dominated by Nile perch and tilapias. In recent years, catches have declined from a peak in the early 1990s. Catch per unit effort appears to have remained stable except for a drop in 1995, however, this is considered dubious because the effort showed a doubling in that year. Limitations of the fisheries data collection system for the Tanzanian sector of Lake Victoria are highlighted and discussed

Managed realignment for habitat compensation: Use of a new intertidal habitat by fishes

Managed realignment has become an increasingly common mechanism to increase the efficiency and sustainability of flood defences, reduce defence costs or compensate for habitat losses. This study investigated the use by fishes of a new intertidal habitat, created by managed realignment, intended to compensate for the loss of mudflat associated with a major port development. Although broadly similar, statistically significant differences in fish species composition, abundance, biomass, size structure, diversity and diet composition indicate that the managed realignment is not yet functioning in an identical manner to the mudflat in the adjacent estuary, most likely due to differences in habitat between sites. Notwithstanding, similarity in the species composition of fyke catches in the managed realignment and estuary increased annually during the 5-year study period, suggesting that the mudflat in the realignment is still developing. Indeed, the site will inevitably change over time with accretion, establishment of vegetation and possibly development of creeks. This will not necessarily prevent the aim of the realignment scheme being achieved, as long as sufficient suitable mudflat remains

Notes for guidance on preparation of research reports, research dissertations and scientific papers

The notes for guidance on preparation of research, research dissertations and scientific papers are meant to assist researchers on how to achieve a successful presentation, writing a technical report or research paper. This comprises some simple rules that have helped many inexperienced writers to get started, and have also helped more experienced writers to get out of a hopeless tangle of observations and inferences. (PDF contains 65 pages

Report on Fourth FIDAWOG Workshop held in Kisumo, 16 to 20 August 1999: summary of proceedings

The FIDAWOG workshop held at the Tom Mboya Labour College in Kisumu was the fourth stock assessment workshop held under the LVFRP programme. There were two main objectives: training in paper and report writing and presentation, and presentation of research results collected to date

The general anti-avoidance rule

Although a general anti-avoidance rule (GAAR) being enacted within a country is becoming increasingly more common, the presence of a GAAR is generally overlooked and thus its effect left unstudied. In this paper we provide an initial investigation by studying the effect that the presence of a GAAR within a country has on corporate tax avoidance behaviors. Using an indicator for the enactment of a GAAR within a specific country, we find a statistically and economically significant increase in aggregate tax collections and a statistically and economically significant decrease in firm-level tax avoidance. Additional analyses show that the firm-level results are strongest for firms with higher levels of tax avoidance, for countries with lower levels of tax enforcement prior to the implementation of a GAAR, and for countries where the burden of proof lies, at least partially, with the taxpayer. In final analyses, we find that the GAAR is associated with a decrease in the volatility of reported ETRs

Assessing fisheries and environmental impacts and proposing policy recommendations for sustainable development of Mekong River Basin

Since its establishment in 1995, the Mekong River Commission (MRC) has been involved in the collection of data and the development of models, both conceptual and mathematical, aimed at demonstrating and improving the understanding of the functioning of aquatic ecosystems and links between the people and the river, and aiding policy and decision-making in the Lower Mekong River Basin. The objective of basin-wide fisheries and environmental assessment is to provide clear and comparable information on the impacts of proposed hydropower and other key sector developments on the aquatic ecosystems and their fisheries and other aquatic resources of Mekong River downstream of the China border, inclusive of the Tonle Sap Great Lake and the Mekong Delta. The DRIFT Flows process and Decision Support System (DSS) referred to in the MRC Council Study as the BioRA-DSS, were used to organise existing MRC data, information in the international scientific literature and expert opinion from a highly-qualified and experienced team of river scientists to provide a systemic and systematic picture for the LMB, Tonle Sap River, Tonle Sap Great Lake and the Mekong Delta ecosystems in terms of (1) their ecological condition; (2) possible future changes in condition as a result of development-driven changes in the water flow, sediment supply and transport, water quality, and lateral and longitudinal connectivity as described through the evaluation of the water-resource development scenarios; and (3) predictions of change in abundance/area/concentration (relative to baseline) for a range of key fish and other bioresources indicators. Last but not least, policy recommendations were proposed for Mekong countries’ Prime Ministers and Ministers of Water Resources for basin planning and sustainable management and development of the Mekong River Basin

Optimising hydropower development and ecosystem services in the Kafue River, Zambia

Fisheries are an important resource in Zambia, but are experiencing overexploitation and are under increasing pressure from external development activities that are compromising river ecosystem services and functioning. One such system is the Kafue Flats floodplain, which is under threat from hydropower development. This paper reviews the impact of potential hydropower development on the Kafue Flats floodplain and explores mechanisms to optimise the expansion of hydropower whilst maintain the ecosystem functioning and services the floodplain delivers.Since completion of the Kafue Gorge and Itezhi-tezhi dams, seasonal fluctuations in the height and extent of flooding have been suppressed. This situation is likely to get worse with the proposed incorporation of a hydropower scheme into Itezhi-tezhi dam, which will operate under a hydropeaking regime. This will have major ramifications for the fish communities and ecosystem functioning and likely result in the demise of the fishery along with destruction of the wetlands and associated wildlife. To redress the problem it is recommended that an environmental flows study is conducted, as initiated by World Wildlife Fund, to protect the existing ecosystem services provision and optimise hydropower development, thus ensuring sustainability of the aquatic resources of the Kafue Flats for future generations

Diel variations in the assemblage structure and foraging ecology of larval and 0+ year juvenile fishes in a man-made floodplain waterbody

© 2016 The Fisheries Society of the British Isles. This study investigated diel variations in zooplankton composition and abundance, and the species composition, density, size structure, feeding activity, diet composition and prey selection of larval and 0+ year juvenile fishes in the littoral of a man-made floodplain waterbody over five 24 h periods within a 57 day period. There was a significant difference in the species composition of diurnal and nocturnal catches, with most species consistently peaking in abundance either during daylight or at night, reflecting their main activity period. There were no consistent diel patterns in assemblage structure or the abundance of some species, however, most likely, respectively, due to the phenology of fish hatching and ontogenetic shifts in diel behaviour or habitat use. There were few clear diel patterns in the diet composition or prey selection of larval and 0+ year juvenile roach Rutilus rutilus and perch Perca fluviatilis, with most taxa consistently selected or avoided irrespective of the time of day or night, and no obvious shift between planktonic and benthic food sources, but dietary overlap suggested that interspecific interactions were probably strongest at night. It is essential that sampling programmes account for the diel ecology of the target species, as diurnal surveys alone could produce inaccurate assessments of resource use. The relative lack of consistent diel patterns in this study suggests that multiple 24 h surveys are required in late spring and early summer to provide accurate assessments of 0+ year fish assemblage structure and foraging ecology