• Notes on the mangrove swamps of Kenya.

      Graham, R.M. (1929)
      It is estimated that the Mangrove Swamps in Kenya cover an area of about 180 squares miles. All have been gazetted as forest reserves. Since only four creek systems have been surveyed, it is obvious that the area given is only approximate, but the composition of the gazetted areas does not vary very much. Judging by the four swamps that have been surveyed, it seems probably that only about two-thirds of the total area can be classed us merchantable forest. The remainder consists of scrub mchu, liIana and undersized mkandaa. Of the merchantable forest, probably 70% consists of well-grown mkoko, with scattered muia and mkandaa, and 30% of badly-shaped mkandaa which, however, finds a market as fuel.
    • The Biology of Trout in Kenya Colony.

      Van Someren, Vernon D. (River Research CentreKenya, 1950)
      Apart from Copley's papers (1940 a, b, 1947, 1950), there have been no scientific observations made on trout biology in East Africa, though van Someren has also published a few preliminary observations (1946). Trout were first introduced into Kenya Colony in 1905, and there are now many miles of trout water available in the Colony; the history of their introduction has been described by Copley (1938, 1940 a and b). Management of these trout waters has been largely empirical and remarkably successful, though the need has now been recognised to support such management policies by biological data. Because such data are largely lacking, the work at the Research Centre, which has gradually increased in scope as facilities became available, has been directed mainly towards the collection and assessment of facts on the natural history of our exotic trout in all aspects. Two and a half year's work has seen the amassing of a very large quantity of such factual data, and the results are presented herewith. The reader will find this first account of trout biology purely descriptive and analytical; very few experimental results are described, and there are only occasional references to aspects and policies of fishery management. Proposals for the later can only be based on the scientific data now being made available, and will follow naturally as results become known and confirmed by experimental procedure. Thus in time will the rivers yield the fullest of which they are capable.
    • Annual report of the East African Fisheries Research Organization, 1952.

      East African Fisheries Research Organization (East African Fisheries Research Organization (EAFRO)Jinja, Uganda, 1952)
      The scientific activity of the former East African Fisheries Research Organization is briefly reviewed. The research refers to the Lake Victoria region.
    • Preliminary Survey of the Pelagic Fishes of East Africa.

      Williams, F. (Her Majesty's Stationary OfficeLondon, UK, 1956)
      The scope of the survey is defined. A short description is given of the hydrographic and climatic conditions of the East African coastal region. A full description is made of the gear used in multiple trolling from M.F.V. "Research". The efficiency and limitations of the gear are discussed, with suggestions for improvements in the method. Most effective trolling speed was 5-6 knots. The twenty-eight species of fish taken by trolling are fully described. The catch, seasonal abundance and distribution of the pelagic fishes are discussed. Some species - Caranx, Sphyrcena, Aprion and Plectropoma appear to be present throughout the year. They are more numerous during the N.E. monsoon when the gonads are in the spawning condition. Coryphcena hippurus makes an inshore spawning migration from January to June. Due to migrations other pelagics such as the Scombrids show a marked seasonal abundance, but little is known as yet of the reasons for the migrations. Shoals of tunny-like Scombrids have been seen in large numbers but fish were not taken from them by trolling. Monthly details of the catch of fishes are tabulated for each section of the coast. The average catch rate for the whole of the survey was 1•14Ibs./line/hour. The monsoon conditions have a direct bearing on the productivity of the fishery, especially in the S.E. monsoon. Fish are almost entirely restricted to within the 100 fin. line. Largest numbers are taken where a shallow shelf extends out from the fringing reef or over the shallow off-shore banks. Reasons for this distribution are advanced. It is concluded that multiple trolling alone by a fishing boat the size of "Research',' would not be commercially profitable. However the expansion of the native fishery for pelagic fishes is advocated. Two possible methods of development by using trolling are given. Suggestions are made for the capture of tunny-like shoals by means of a purse seine or the live bait technique, together with the use of deep long lines for tunny and gill nets for the capture of the smaller shoaling Carangids and Scomberomorids. The future biological investigations to be carried on the pelagic fishes are discussed.
    • Report to the Government of Kenya on the Sea Fisheries of Kenya June-July 1958. Based on the work of J.A. Crutchfield (FAO Technical Assistance Fishery Expert).

      Food and Agriculture OrganizationRome, Italy, 1958
      There is a widespread feeling among government and business officials that expansion of the Kenya coast fisheries is impeded by an inadequate and restrictive marketing structure. Various plans for improvement of the industry have been put forward by the trade -and by the Game Department's Fisheries Division, but all have been subject to vigorous objections from one or more groups concerned. The Kenya government therefore requested the Food and Agriculture Organization to assign a qualified person to survey the industry and to recommend measures for improve the marketing of sea fish. This request was subsequently broadened to include an appraisal of the need for a loan fund for Arab, African and Bajune soa fishermen.
    • An Investigation of the Biology and Culture of an East African Oyster Crassostrce cucullata.

      Van Someren, V.D.; Whitehead, P.J. (Her Majesty's Stationary OfficeLondon, England, 1961)
      CrassostrtZa cucullata (Born) is the most important edible oyster of the East African coast, and is .a purely littoral species occurring intertidally on open reefs, mangrove roots and creek rock exposures. Heavy commercial exploitation ofoyster beds on the Kenya coast has led to almost complete destruction of these beds, and in all areas the rate of natural regeneration and recovery of beds appears practically negligible, or at the best, an extremely slow process. Exploitation of beds, hitherto unlicensed, is now strictly controlled by Government. A survey of the biology and ecology ofoysters was carried out between September 1953 and August 1954, with further brief visits in October 1954 and September 1956, with particular reference to conditions in Mida Creek, one ofthe largest natural beds of oysters on mangroves. Here two forms of oyster occur; one, a spiked form growing on mangrove roots at higher tidal levels, and the other a flat form, growing at the lower levels. These appear to be distinct species, the latter being recognizable as C. cucullata; no attempt 4as been made to determine the identity ofthe former, which is referred to as Species A. The tidal and certain physico-chemical conditions in Mida are described in detail, these being different from those of the open shore, owing to the geographical formation of the Creek. The particular differences in each oyster zone are well marked. The oysters themselves are confined only to the eastern fringes of the mangrove forests, a spatial distribution which limits their abundance, and which may be due to the habit ofthe settling spat. They occur also on old reef rock expanses, and are phoretic on the abundant mollusc Terebralia palustris Brug. Zonation on the mangrove roots is distinct, and bears a strict relation to tidal levels. Temperatures, salinity and rainfall figures were noted, and their seasonal and local variations are described. Weekly dissections of adult oysters were made to determine spawning rhythms. While spent oysters may be found in armost any week ofthe year, and a low level ofspawning is continuous, nevertheless spawning sho~s two maximal periods coinciding with the onset of the rainy seasons in the year. The environmental factors related to spawning are complex, and it is suggested that (a) maximal water temperatures oYer 85"F (29'S°C), (b) the immediate onset of rain and (c) a fall in salinity are jointly responsihle for major spawning activity. While natural spat is very rare on all Kenya oyster beds, nevertheless a variety of spat collecting devices tried at Mida showed that spat would settle readily on Mangalore tile collectors, and shell culch strung on wires. The importance of cleanliness of spat collectors is not yet fully established for Kenya conditions and further trials are required both in this connection and that of the most suitable method in which to arrange the collector and the best type of collector. Itis, however, certain that some form of cultural method, using spat collectors, is fully practicable. While spat may settle at almost any time of the year, the heaviest spatfalls occurred at the beginning of, and during, the rainy seasons of November/December and April/May, the latter season providing maximal spatfall. The duration of free swimming larval life is not, however, known. All spat collected settled within a few inches ofground level, and appeared to be that of C. cuculla!a. Under natural conditions spatfall is fractional only, and the evidence suggests that the spat settle by preference on hard surfaces, mangrove bark being a second "choice". The conditions influencing settlement of spat are discussed. Growth of spat collected at Mida is very fast, averaging about 0·6 em a month; at only seven months the young oysters have reached the average adult length, but not thickness; thickness is added during the second year of life, and artificially grown oysters reach marketable size in about 2! to 3 years. Spat from elsewhere, grown at Mida, does not grow so fast, nor does Mida spat at levels above their normal tidal zone. Growth or survival of spat under pennanent submerged conditions is not known• Natural mortality of spat is not particularly heavy, nor apparently are there many serious natural predators. The growth of spat may vary according to season, but once adult, the oysters apparently cease to grow. Size at first maturity is not known. The preliminary results indicate that artificial culture of these Kenya C. cucul/ata oysters on shell culch strung on wires, and on tile collectors, would be practicable and economic, and indeed essential if exploitation is to continue at its present level. Possible cultural methods are discussed, and in places such as Mida or Ngomeni reef, there are large potentially productive areas which could be utilised for such culture.
    • Re-investigation of clino-ferrosilite from Lake Naivasha, Kenya.

      Bown, M.G. (1965)
      The clino-ferrosilite from the lithophysae in an obsidian fl'om Lake Naivasha, Kenya, originally examined by Bowen (1935), has been shown to be substantially pure FeSiO3, with about 5 % MnSiO3 in solid solution. It has the same space-group, P21/c , as clino-enstatite and pigeonite. The unit-cell dimensions are a = 9.718 A, b = 9.088 A, c = 5.239 A, ~b = 108~'27'. These do not conform to the scheme proposed by Brown (1960): reasons are given why this was not unexpected.
    • Report on Kenya Fisheries 1967.

      Kenya Fisheries Department (Fisheries DepartmentNairobi, Kenya, 1967)
      The Report on Kenya Fisheries 1967 summarizes the activities that occurred within the Fisheries Industry in Kenya.
    • Report on Kenya Fisheries 1968.

      Kenya Fisheries Department (Fisheries DepartmentNairobi, Kenya, 1968)
      There was a further increase in production of fish and other marine products by Kenya fishing industry in 1968.
    • A brief report on a survey of the fish and fisheries of the Tana river, with special reference to the probable effects of the proposed barrages.

      Mann, M.J. (East African Freshwater Fisheries Research OrganizationJinja, Uganda, 1969)
      The construction of several barrages, in order to develop the hydroelectric and irrigation potential of the Tana river, has been proposed and the probable effects of these developments upon the fish and fisheries of the area has been investigated. Briefly in the highest reaches the sport fishery will be unaffected, in the, middle reaches the sparse subsistence fisheries will be only slightly inconvenienced but in the terminal reaches of the river the subsistence and commercial fishing enterprises are expected to be seriously reduced by the progressive re-regulation of river-flow. However each new dam will support a new and productive reservoir fishery and with proper development the annual yield of fish from the Tana basin is expected to increase considerably.
    • Monex Kenya.

      Johnson, D.R. (University of Miami, Rosenstiel School of Marine and Atmospheric SciencesMiami, USA, 1980)
      This report presents physical oceanographic station data collected during seven cruises along the coast of Kenya from April to December, 1979. Vertical profiles of horizontal currents, temperature and salinity are presented for each station. In the last part, horizontal sections of alongshore currents, temperature and salinity are given for the months of July (height of the SW monsoon season) and December (beginning of the NE monsoon season).
    • Aid to Fisheries at Lake Turkana - Evaluations and Recommendations: Report by an Advisory Group Appointed by NORAD September 1980.

      Jorgensen, Knut; Raa, Jan; Saetersdal, Gunnar; Williams, Johan; Broch-Due, Vigdis; Storas, Frode; NORAD (NORADNairobi, Kenya, 1980)
      In 1967 Kenya made a request for Norwegian assistance to develop the fisheries of Lake Turkana. A project was formulated and agreed and its first phase started in 1970. Norway provided financial and technical assistance to this project. During the first years personnel from the Norwegian Voluntary Service worked as advicers in boat-building and in the management of the Turkana Fishermen's Cooperative Society (TFCS). A fishing master conducted trial fishing. The project was equipped with a number of fishing boaus, one 36 ft. research vessel, fishing gear, tools for boat bUilding and some vehicles for the staff and the Society. The Society was also provided with some financial support. During these years the main efforts were directed towards building up the Turkana Fisheries Cooperative Society. In 1977 its monopoly over the fish sale from the fishermen and the further wholesale of processed fish was reinforced by the Kenya government. Rules and regulations for the fishing in the lake were also established in order to protect the fish resources against over­ fishing. In 1974 a Norwegian consultant recommended the establishment of a fish pro­ cessing plant at Lake Turkana. In 1975 the Government of Kenya submitted a request to Norway for assistance in building such a plant. In 1976 and 1977 NORAD carried out feasibility studies of a fish processing plant including evaluations of marketing conditions for the economics of frozen fish produc­ tion. The building of a plant with freezing facilities was recommended mainly on the basis that such an expansion would be economically beneficial to the TFCS. An agreement between Kenya and Norway concerning the building of a plant was signed in 1978. The project was to include a processing unit, storage facilities for frozen fish, refrigeration machinery, icemaking machinery, generators and other facilities. From 1977 NORAD provided a manager for the TFCS, from 1978 a fish-processing expert and from 1980 also a refrigeration machinery expert and a marketing expert. The building of the new factory started in May 1979 and will be completed during the first quarter of 1981.
    • Cruise Report R/V ”Dr. Fridtjof Nansen” Survey of the Abundance and Distribution of Fish Resources off Kenya 7-15 December 1982

      Iversen, Svein A. (Institute of Marine ResearchBergen, Norway, 1982)
      Objectives for the survey were as follows: (1) Acoustic/fish survey whole shelf (200 m); (2) Detailed study of fish distribution Malindi Bank; (3) Trap/longline fishing in various localities including Kenya Bank; (4) Hydrographic sections.
    • Oceanographic Features Along the Kenyan Coast: implications for Fisheries Management and Development. Special Project Report.

      Ochumba, Peter B.O. (Oregon State University, 1983)
      This Special Project Report has the following major headings: 1. Introduction (a) Position; (b) Nature of Coastline; (c) Fisheries Status. 2. Oceanography (a) Currents and Water Masses; (b) Local Upwellings and Vertical Mixing Between the Water Masses; (c) Primary Productivity and the General. 3. Fish stocks and fisheries; (a) Crustaceans: (b) Spawning, Breeding and Recruitment Activity; 4. Stock assessment: Maximum Sustainable Yield (MSY) Calculations; Along the Kenyan Coast from the Surplus; Production Model 5. Management: (a) Possible Management Strategies; (b) Issues for International Fishery Management. 6. Developments: Industrial and Foreign Fishing. 7. Recommendations. 8. Literature cited. 9. Appendix figures 1-20 and Tables 1-3.
    • Offshore Trawling Survey Kenya: Project Findings and Recommendations -- FI:DP/KEN/74/023 Terminal Report.

      Food and Agriculture Organization of the United Nations (Food and Agriculture Organization of the United NationsRome, Italy, 1983)
      The survey described in this project terminal report was planned to provide detailed and reliable data on the demersal resources in the waters outside the reef area, to be used eventually for a pre-investment study for development of an offshore (trawl) fishery.
    • The Impact of River Discharges on a Kenya Coral Reef Ecosystem - the physical processes. Part Two: Effects on the Malindi-Watamu Coastal Environment.

      Giesen, W.; Van de Kerkhof, K. (Catholic University of NijmegenNijmegen, Netherlands, 1984)
      This study was carried out on the fringing reefs near Malindi Watamu, Kenya, in the period October 82 to May '83 as a part of the 'Watamu Reef Expedition'. Participants of this expedition were students of the Laboratory for Aquatic Ecology and the Department of Human Geography, both of the Catholic University of Nijmegen, the Netherlands. The aim was to quantify and qualify coral death to assess the contribution of certain factors of disturbance to the decline of these reefs, and to assess the impact of changes in the reef on the coastal inhabitants. Our part in this study consisted of an attempt to quantify and qualify the physical characteristics of the reef environment. Special attention therein was paid to the increased influx of terrestrial silt originating from the Sabaki river, which is one of the most conspicuous factors contributing to the disturbance of this marine milieu. The report has been subdivided into two parts: the first deals with 'The Athi (Sabaki) river basin', and the second with effects on the Malindi-Watamu Coastal Environment’.
    • Tudor Creek, Mombasa: The Early Life History Stages of Fish and Prawns 1985. Overseas Development Administration, Research Project R3888.

      Grove, S.J.; Little, M.C.; Reay, P.J. (Plymouth PolytechnicPlymouth, UK, 1986)
      The project was based at KMFRI headquarters in Mombasa, with Tudor Creek (a fully saline area of mangroves, mud and open water) as the study area. Sampling mainly involved the use of plankton nets and fine-meshed beach seines, in all months from February to November 1985. Sampling frequencies of hours, days and weeks were also employed in order to cover the diel, circatidal, semilunar and lunar cycles. From the samples, prawn post-larvae, fish eggs and larvae, and juvenile fish and prawns were sorted, identified as far as possible, and counted in order to provide data on their occurrence, distribution and abundance. Records of temperature, and some other abiotic parameters, were also maintained. 'l'he fish and prawn fauna of Tudor Creek, is described from the results of the seine-net sampling and is found to include 6 species of penaeid prawn and 135 species (49 families) of teleost fish; additional families were recorded only as larval stages in the plankton. Many of the fish occurred as juveniles, but very few of these were species commercially exploited on nearby reefs and trawling grounds. Differences have been found between the creek mouth and inner creek in terms of both planktonic and juvenile stages, and are associated with a gradient of decreasing depth and dissolved oxygen concentration, and increasing temperature and turbidity from the mouth inwards. One of the' most conspicuous trends has been the decrease in fish egg density and diversity along this gradient, which suggests that while the creek can be regarded as a fish and prawn nursery area, it is not an important spawning ground, at least for pelagic spawners. The existence of the gradient also results in tide-related changes in egg-density which are probably lest explained in relation to the tidal incursion of egg-rich coastal water into the creek rather than to tidal spawning cycles of adult fish. The latter have not been discounted, however, and may emerge from further analysis of data from individual taxa. No clear indication of general systematic seasonal changes in either the planktonic or Juvenile stages were found, but the lowest catch-rates of some species of juveniles occurred during the early part of the SE Monsoon (April/July). Again further analysis of data from individual taxa of both planktonic and juvenile stages, and of the size-frequency data collected; may reveal clearer evidence of seasonal periodicity. The results are discussed in relation to the literature available on similar ecosystems in other tropical areas, and in relation to the major problems encountered in carrying out the work. It is concluded that much has still to be learned about the role of mangrove creeks as nursery areas, and also that this role is important in the context of future fisheries management and environmental monitoring with this application in mind, it is recommended that future work should concentrate on the post-settlement juvenile stages rather than on the planktonic stages, and an argument is presented to support this view.
    • Kenya-Belgium Project. Report on the Physiological Respiratory Adaptations of Oreochromis niloticus L.

      O'Omolo, Samson; Kidi-Okoth, Brigitte (Antwerp State UniversityAntwerp, Belgium, 1986)
      The main objective of this work was to investigate physiological respiratory adaptations of Oreochromis niloticus to hypoxia under different temperature conditions. This African cichlid is widely distributed around the world where temperature is suitable for its growth and reproduction. In many countries it was introduced for vegetation control, pond culture, recreational and commercial fishing, because of its excellent aquaculture potential, fast growth, omnivorous feeding habit and tolerance to low water quality. Like many other cichlids it is also known for its tolerance to temperature variations. However, from the physiological, ecological and economical points of view, such important aspects like rate of thermal acclimation temperature acclimation, critical temperature and oxygen pressure still remain to be elucidated.
    • Trial Fishery in Lake Turkana Kenya: Western Shores, September 1986 - March 1987.

      Kolding, J. (Institute of Marine ResearchBergen, Norway, 1987)
      This report concerns the datas collected so far, i.e. from September 1986 to March 1987. It should primarily be regarded as an evaluation of the methods and data collecting system. The attempted conclusions are, due to the limited material in terms of numbers of investigations and geographical and seasonal coverage, based on very weak foundations. The main aim of this report is to provide the members of the stock assessment group with an updated review of the latest progress.
    • Netherlands Indian Ocean Programme: Part 3. Kenya Shelf And Coastal Ecosystems.

      Netherlands Marine Research Foundation (Netherlands Marine Research FoundationThe Hague, Netherlands, 1990)
      The main goal is a study of the effects of the monsoonal regime on coastal marine systems. In particular the following seasonal effects will be considered: (1) the seasonality in productivity of surface waters. the structure of pelagic and benthic systems and sedimentation and exchange processes; (2) inland erosion and erosion of degraded mangrove systems and increased siltation of coastal areas; (3) changes in growth of seagrasses and corals due to siltation. increased nutrient levels and temperature increases; (and 4) changing inputs of nutrients. particulate matter and inorganic pollutants from (semi-) terrestrial origin. including mangrove systems. Long-term climatological changes will be considered as well. in particular (l) the contribution of coastal wetlands to the greenhouse effect through the production of methane; (2) tracing of changes in precipitation over the last 10.000 years in coastal sediments; and (3) changes in coral growth related to sea-level rise.