Characterization and Space-Time Downscaling of the Inundation Extent over the Inner Niger Delta Using GIEMS and MODIS Data

The objective in this work is to develop downscaling methodologies to obtain a long time record of inundation extent at high spatial resolution based on the existing low spatial resolution results of the Global Inundation Extent from Multi-Satellites (GIEMS) dataset. In semiarid regions, high-spatial-resolution a priori information can be provided by visible and infrared observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). The study concentrates on the Inner Niger Delta where MODIS-derived inundation extent has been estimated at a 500-m resolution. The space-time variability is first analyzed using a principal component analysis (PCA). This is particularly effective to understand the inundation variability, interpolate in time, or fill in missing values. Two innovative methods are developed (linear regression and matrix inversion) both based on the PCA representation. These GIEMS downscaling techniques have been calibrated using the 500-m MODIS data. The downscaled fields show the expected space-time behaviors from MODIS. A 20-yr dataset of the inundation extent at 500 m is derived from this analysis for the Inner Niger Delta. The methods are very general and may be applied to many basins and to other variables than inundation, provided enough a priori high-spatial-resolution information is available. The derived high-spatial-resolution dataset will be used in the framework of the Surface Water Ocean Topography (SWOT) mission to develop and test the instrument simulator as well as to select the calibration validation sites (with high space-time inundation variability). In addition, once SWOT observations are available, the downscaled methodology will be calibrated on them in order to downscale the GIEMS datasets and to extend the SWOT benefits back in time to 1993.

Estudio de la respuesta al potasio, usando Aspergillus niger van tieghem en varios suelos de Nicaragua

Se midió la respuesta a la fertilización con potasio, usando el método de Mehlich para potasio soluble con Aspergillus niger, en cuatro suelos de Nicaragua que contenían 370, 690, 1450 y 3500 libras de K20 por manzana respectivamente. A estos se le aplicaron tratamientos de 0, 50, 100, 150, 300, 500, 600 y 1,000 libras de K20 por manzana. Entre 50 y 150 lbs/mz. de K20 aplicadas, no hubo respuesta. Aplicaciones de 300 lbs/mz. produjeron respuesta en relación proporcional inversa al contenido de K20 salubre de los suelos. Aplicaciones de 500 y 600 lbs/mz. produjeron la misma respuesta y sus efectos estuvieron también en relación inversa al contenido de K20 soluble. Las aplicaciones de 1,000 lbs/mz. produjeron respuesta en todos los suelos, excepto en el D alto en K20 disponible. El grado de respuesta concordó con el contenido de K20 extraible en HC1 0.1N.

Fresh and brackish water shrimps of economic importance in the Niger Delta

In the author’s opinion, extremely little is known of fresh and brackish water species, i.e. those supporting the traditional artisanal fisheries and most likely to include suitable candidates for aquaculture. The immediate purpose of this paper is to document the species which are encountered in artisanal fisheries, give available background information on them relevant to fisheries and aquaculture work, and to provide a means for their identification in the field by nonspecialists. Scope of Coverage the "Niger Delta" in the title reflects the geographical area of the author’s personal experience. For purposes of identification, the scope of the paper is West African for brackish species, and Nigerian for freshwater species

Potentials for fisheries in the Niger Delta: Another green light for self sufficiency in regional food production

A discussion is presented on the potential for fishery development in the Niger Delta region, considering engineering activities and food production potentials of the freshwater zone and immediate hinterland, the brackishwater mangrove swamps and the estuaries. An examination of current trends in the environment indicates that a possible solution to improved exploitation of the region lies in hydraulic engineering, the manipulation of environmental conditions through varying freshwater and seawater inputs so as to increase aquatic and wetland productivity

Preliminary survey of parasites of Clarias in the Niger Delta area of Nigeria

A total of 160 Clarias lazera were collected with line hood between April and June 1984 from the Niger Delta area and observed for the presence of parasites. The results revealed the presence of three classes of endo-parasites: Trematodes (47%), nematodes (46%) and cestodes (7%). It was found that, the parasites have great affinity for the spleen (34%) and the liver (28.3%). Also, smaller fish habored more parasites than large fish. Though the investigation is still continuing, the study reveals the presence of parasites in Clarias and calls for measures to prevent wide-spread infestation in fish ponds and suggests treatment of infested fish

Some experiments on commercial pond fish culture in the tidal mangrove area of Niger delta of Nigeria

A pilot fish culture project was initiated by Shell Petroleum Development Company of Nigeria Limited in 1981 with specific aims and objectives. Site selection, survey, pond construction method and fish production with regards to experiences gathered and gained, problems and solutions so far obtained are discussed. Trials of freshwater fish species to check their adaptability to brackishwater ponds were carried out and the promising results of the growth rate of these species when compared with the traditional local brackishwater species selected for culture are reported. The extension programme so far carried out is briefly described

Age and growth of Heterotis niloticus around Pategi in the middle River Niger, Kwara State

Biological studies of Heterotis niloticus were conducted for three years in the middle River Niger. Scales were found to be the most suitable structure in ageing Heterotis which was validated by length/histogram curve. Annual rings were found to be formed between March to June. Growth was rapid in the first two years and they reached sexual maturity at 2 years. The male grow longer while the female are bulkier. The length-weight relationship of male and female Heterotis did not differ significantly and the resulting equation for male was W = 1.25L super(2.5) and W = 1.6L super(2.7) for females respectively where W = weight (g) and L = total length. The total length to body scale relationship was found to be L = 14.3R super(2.6) where (R = oral radius of scale Heterotis growth was found to be allometric

Harnessing the fishery potential of man-made lakes for the partial commercialisation of Niger River Basin Development Authority, Minna, Nigeria

Niger River Basin Development Authority Minna (NRBDA) is one of the eleven river basins in Nigeria now undergoing transition towards partial commercialisation. In the light of this the need to be self-sustaining through exploration and exploitation of every possible areas along their operation to yield revenue cannot be over-emphasized. Therefore it is most pertinent to consider fisheries activities along their water bodies as one of the major sources of revenue by organising the local fishermen operating along the water into cooperative bodies and made to pay for fishing rights. Strategies to accomplish this objective is highlighted. The need to embark on aquaculture projects by construction of fish ponds at suitable sites along the reservoirs and developing the recreational potentials of their water bodies as sources of revenue is also stressed

The incidence of Nypa fruticans (Wurmb) and its impact on fisheries production in the Niger Delta mangrove ecosystem

Nypa fruticans occurs in Bayelsa, Rivers, Akwa Ibom and Cross River State, Nigeria; invading an estimated area of 821 Km super(2) mangrove dominated swamps. Human activities such as tree felling, urbanization, oil and gas exploration and exploitation and other activities led to the interference in the normal mangrove by the Nypa palm. Lack of utilization by the local population of the Nypa palm as in into-pacification has increased the population over the years. The effect includes the reduction in primary and secondary productivity, disruption of food chain and erosion of riverbanks. The eradication of the Nypa palm from the Niger delta mangrove ecosystem and replacement with red and white mangroves will restore the ecosystem health and enhance biological diversity

Feasibility of adopting integrated rice-cum-fish culture system to enhance the development of conventional aquaculture participation in Niger State

In a survey conducted to find out the status of integrated rice-cum-fish culture in Niger State, Nigeria, 0.37 ha of Fadama wetlands was utilized for rice-cum-fish culture and at experimental stage. In the case study of this rice-cum-fish model, the Nile Tilapia (Oreochromis niloticus) was involved. The result was that 1,4720 kg/ha/yr could be produced using chick manure application under rice-cum-fish culture model. The available records reveal that 233,079 ha out of 495,000 ha of estimated Fadama in Niger State was used for rice cultivation in 1997. If 233,079 ha were to be used for integrated rice-cum fish culture, it is estimated that 343,092 mt of fish (Oreochromis niloticus) could be produced per year. The fish demand in Niger State in 2002 was 50,000 mt. The NPK application under rice-cum-fish production gave the best rice production estimated at 43,968.0 kg/ha/yr. The percentage increase in rice yield as well as increase in net income due to introduction of fish was 10.1 % and 54.4% respectively. The culture system is therefore recommended for adoption towards greater participation in aquaculture development by the farmers

Improved fisheries technologies and approaches for their dissemination: a case study of Niger State

Technology generation and dissemination are important components of rural transformation programmes. Nigerian fisheries sub-sector is still hampered by low productivity (especially in aquaculture) and low output (capture fisheries and post-harvest technologies). Research institutions and the Universities have made efforts in developing improved technologies to find solution to these problems, yet the level of adoption of the technologies remain low. This is due to a combination of various factors among which are faulty agricultural policies; institutional framework and unfavourable socio-economic environment. Niger State plays an important role in production in Nigeria and host the only research institute with the mandate in inland fisheries. It is important therefore to know the effectiveness of various extension approaches used in disseminating the technologies developed and their impact on adopters. Forty fishers were randomly selected in Shiroro L.G.A. of the Niger State and interviewed. The study probed into their socio-economic characteristics, traditional practices, extent of awareness and adoption for fisheries technologies and the effectiveness and impact of various approaches used by the extension organizations to disseminate the technologies. The results show that the economically active age group of the fishers was in the range of 20-50 years (87.5%). Males (95%) dominate the fisher population. 47.5% of the respondents have average household size of 6-10 and 57.5% were below primary school in educational attainment. Only 57.5% belonged to cooperative societies, while 90.0% of the fishers have no access to credit other than personal finance. Majority of fish-farmers (60%) operate at homestead level with pond size less than 50 square meter, stock under polyculture fishing methods are at subsistence level, while 67.5% of processors use mud-oven to cure, by smoking, freshly caught fish. Disseminated aquaculture technologies have low level of awareness (5-20%) and adoption (2.5-22.5%). For capture fisheries and post-harvest technologies awareness levels of 47.5-72.5% and adoption levels of 27.5-50.0% were recorded. Method demonstration (87.5%), result demonstration (75.0%) and field days (47.5%) are the major approaches used by the ADP. Respondents were of the opinion that method demonstration (65%), result demonstration (57.5%) and field day (30.0%) are effective. 62.5% of respondents had enhanced income due impact of extension activities

Observations on the ecology of Hepsetus odoe, Bloch, 1794 (Pisces: Hepsetidae) in Epie Creek floodplain, Niger Delta, Nigeria

The distribution, abundance, age and growth, the food and feeding habits, condition factor and reproduction of Hepsetus odoe in the Epie Creek Floodplain (Nigeria) was studied. H. odoe occur in the creek, swamp channel and lake. It is a very common, abundant and one of the major commercial species. A total of 457 specimens weighing 76.90 kg were caught during the period of investigation. The catches were more abundant in the dry season than in the wet season. The total length ranged from 10 cm to 46 cm while the weight varied between 50 g and 900 g. Six distinct components or year classes were observed using Bhattacharya's method. A growth exponential value 'b' was 3.35 with condition factor, 'k' values ranging from 0.69 to 0.83. The main diets of Hepsetus odoe were fish, including crustaceans (shrimps) and insects. The mean fecundity was 6060 plus or minus 358 eggs (range 2,769 to 6.667 eggs). The ova diameter of H. odoe was found to range from 2.2 mm to 2.6 mm with overall mean = 2.4 plus or minus 0.1)

Review paper on the production trials of rice-cum fish culture - a transferable concept into Niger State, Nigeria

This paper reviews the production trials of rice-cum-fish culture. Rice and various fish species using rotation and concurrent methods of cultivation are used. The farming system is mostly practiced and researched in to in Southeast Asian countries. It addresses the problems of high external inputs, sustainable aquaculture, poverty and nutrition in the rural population, insect pests, use of insecticides, weeds control and under-utilization of agricultural lands. The production trials yields are summarized and a summary of annual income per hectare from rice and fish have been given. The yield however depends to a large extent on the species stocked, culture period, fertility of the soil and water, degree of supplemental feeding and culturing methods. The production results are discussed. Niger state is blessed with abundant wetlands/rice fields suitable for the practice. However, ecological differences from country to country and region to region, research and development trials are necessary to ensure a successful adoption of the technology to farmers in the State