Socio-economic and marketing aspects of Laila and Bottom Long Line fisheries in the Kalpitiya peninsula of Sri Lanka

Surrounding Net Fishery (laila) and Bottom Long Line Fishery which operate in the coastal waters of Kalpitiya Peninsula, compete for the same fish resources, resulting in a fishery dispute between the respective fishermen. Both fisheries target demersal as well as mid pelagic fishes, such as travellys (parava), mullets (galmalu) and barracudas (ulava). As the dispute had an adverse impact on the social harmony in the fishing community of the area, a socio-economic survey was conducted to study the underlying factors and to suggest policy measures to resolve the issue. The laila fishermen were resident fishermen in the Kalpitiya Peninsula while bottom long line fishermen were migratory fishermen from Negombo and Chilaw areas in the west coast of Sri Lanka. The Kalpitiya peninsula is located in the North West coast, some 50 km away from the west coast. Although the educational level and literacy rate of the laila community was below that of the bottom long line community, the laila community was economically better off. The net economic returns from laila fishery were superior to that from bottom long line fishery. The boat owner's and crew's share per operation of laila fishery were Rs.3,736 and Rs.947 respectively. The same figures for bottom long line fishery were Rs.588 and Rs.327 respectively. The resource rent from laila fishery was Rs.5,860, however, and much higher than that for bottom long line fishery (Rs.275), showing that the laila fishery exploits the targeted fish resource at a much higher rate compared to bottom long line fishery. This situation badly affects the equitable distribution of resources between the two fishing communities and results in unequal economic gains. Based on the findings of this study, certain input/output controls are proposed to address this problem, among which is the need to increase license fee for laila fishery units to offset the higher exploitation rate of fish resources.

The study of socio-economic aspects of Lake Kimira fisheries after the ban on fishing

Lake Kimira is a minor lake in Bugiri district one of the riparian district of Lake Victoria. It is an important source of livelihood to people living in the neighbouring sub counties; Iwemba in the southwest, Kapyanga in the South and Buluguyi in the East. At the request made to the District Fisheries Officer of Bugiri District, this study was conducted to gather information on the Socioeconomic aspects of lake kimira fisheries after the ban on fishing with regards to fish amounts, marketing, consumption and the perception of the people about the restocking and the ban

Training aspects for a trawling fishery

Trawling experiments carried out by the United Nations Development Programme Project and the Uganda Department of Fisheries, strongly suggest that the trawling method of fishing, if introduced on Lake Victoria, would bring about a tremendous increase in fish production from the lake. It is recognised, however, that before trawling is introduced, its economic, social, technical, biological and manpower implications must be carefully analysed. I now propose to discuss the training aspects of a trawl fishery on Lake Victoria.

Some major unsolved aspects of the dynamics of African fisheries as related to questions of rational development and management

Studies of fish and fisheries in Africa fall in to four phases: the period of fisheries expeditions, ecological investigations, the development phase, and the period of mechanized exploitation. There is need to establish the taxonomic status and ecology of the varied components of the potentially important Haplochromis in Lake Victoria. A comprehensive study of their bionomics and life history, population structure, natality, recruitment and mortality coefficients should be undertaken. Emphasis lo be laid on the study of the ecology, especially breeding behaviour of the economically important c1upeids (Stolothrissa tanganciae and Limnothrissa miodon), in Lake Tanganyika. A comprehensive investigation into the migratory and shoaling behaviour of the Lake Victoria Tilapia to be initiated. Pre-impoundment studies to be undertaken to assess effects of hydroelectric projects of fisheries. Studies on parasites of economically important fishes to be stepped up to assess pathological effects and the biological basis for their control. The role of predators, e.g., Hydrocyon, Lates and Micropterus salmoides in commercial fish populations should be evaluated, and the knowledge gaincd used to effectively manage the fisheries in favour of the more desirable fish stocks.

Fishery resources and some economic aspects of four fishing villages on Lakes George and Edward in the Queen Elizabeth National Park, Uganda

The fishery resources of Lake George and Ugandan waters of Lake Edward are described. The main fish species currently observed in the commercial catches were determined and the reasons of changes in species composition of the catches. that occurred in the recent years, are explained. The fishing activity and some economic and nutritional aspects of four fishing villages, selected among the ten present within the Queen Elizabeth National Park boundaries, are analyzed, In the end some suggestions are given for management of the fishery resources of these lakes.

The potential for further proliferation of water hyacinth in Lakes Victoria, Kyoga and Kwania and some urgent aspects for research

Shore environments of Lakes Victoria and Kyoga with potential for the establishment and proliferation of water hyacinth were identified. They are characterised by: (i) shelter from violent off-shore and along-the-shore wind and wave action (ii) flat or gentle slope under relatively shallow water, and (iii) a muddy bottom rich in organic matter. Such environments are strongly associated with emergent macrophytes of papyrus, Vossia sp and, at times Typha sp where Pistia stratiotes, species of ceratophyllum, myriophylum and nymphaea also occur. In Lake Kyoga association with Vossia sp facilitated establishment of water hyacinth even along wind-swept shores and promoted extension of mats of the two machrophytes into the open lake. Urgent research on water hyacinth is proposed in the areas of nutrient relations, weed biology and on its impact on the biodiversity resource, with particular emphasis on the fishery component. Findings from the research could facilitate formulation of weed control options and alternative resource management strategies. A regional approach to address the water hyacinth menace is highly recommended.

Aspects of the biology of the Lake Tanganyika sardine, Limnothrissa miodon (Boulenger), in Lake Kariba

Juveniles of limnothrissa miodon (Boulenger) were introduced into the man-made Lake Kariba in 1967-1968. Thirty months of night-fishing for this species from Sinazongwe, near the centre of the Kariba North bank, from 1971 to 1974 are described. Biological studies were carried out on samples of the catch during most of these months. Limnological studies were carried out over a period of four months in 1973. Limnothrissa is breeding successfully and its number have greatly increased. It has reached an equilibrium level of population size at a lower density than that of Lake Tanganyika sardines, but nevertheless is an important factor in the ecology of Lake Kariba. The growth rate, size at maturity and maximum size are all less than those of Lake Tanganyika Limnothrissa. A marked disruption in the orderly progression of length frequency modes occurs in September, for which the present body of evidence cannot supply an explanation.

Systems aspects of optical technologies for use in datacommunications

This paper reviews the development of system techniques using advanced modulation formats that have arisen in recent years for use in datacommunications. Simulations are provided to allow comparison of the emerging schemes. © OSA/OFC/NFOEC 2011.

Important aspects when modelling the interaction between surface structures and tunnelling in sand

Tunnelling in urban areas continues to increase and has highlighted the need for a better understanding of the impact of tunnel excavations on existing buildings. This paper considers the influence of surface structures on ground displacements caused by tunnelling in sand through finite element modelling and centrifuge testing. First, the importance of modelling assumptions is evaluated by comparing centrifuge modelling results to finite element modelling results for various soil constitutive models: both a Young's modulus that linearly increases with depth and a power law relation between the soil stiffness and stresses are considered. Second, the most effective soil constitutive model was used to perform a sensitivity study on the effect of different factors governing the structural response. In particular, the effect of the building stiffness and weight on the modification of soil displacements is investigated by introducing a simple surface structure. The use of a no-tension interface between the building and the soil was found to be essential to investigate the effect of weight on gap formation between the soil and the structure, as observed during the experimental tests. Results show the importance of considering the relation between the building weight and the relative stiffness between the building and the soil when assessing the structural response. © 2014 Korean Geotechnical Society.