Fishery
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Item A Preliminary Note on the Breeding And Growth of Tilapia in Marine Fish Ponds On Zanzibar Island(1956/1957) Talbot, F. H.; Newell, B. S.The following notes describe an initial experiment in the stocking of marine fish ponds operated by the Organization with a species of wild Tilapia found in the estuarine reaches of the Mzinga Mzinga stream, at the north-western end of Zanzibar Island. This species had been collected twice previously from Zanzibar. It is closely allied to Tilapia mossambica (Peters) and to Tilapia pangani Lowe, being fairly similar to the latter but differing from it in the lateral line scale count. It is possibly a distinct species, and Dr. Trewavas of the British Museum is working on its systematic position.Item The Bulb Eelworm Disease of Narcissus in Kenya(1950) Nattrass, R.M.The Bulb Eelworm disease of Narcissus species has long been the cause of serious loss Europe. It has only recently (1949) been recorded in Kenya. In appearance the disease symptoms are similar to those usually associated with fungi or bacteria. It is, however caused by an elworm Anguillulina dipsacngItem The Sea Fisheries of Kenya(1950) Allfree, T.E.; Hugh, C.The possibilities of the utilization of the sea fishes off the coast of Kenya has been discussed since 1928 but it was really the late war that focused attention on this matter. Since the war much discussion has taken place and various attempts have been made by individuals and commercial interests to make wealth out of our sea fishes. Our newspapers have also shown great interest in these matters. The time seems appropriate to examine the possibilities for the utilization of our sea fishes and to put before the public a comprehensive view of the whoe question and to discuss the various methods by which advancement can be made.Item The Lung-Fish Protopterus In Central Africa, South of The Zambezi(1962) Weir, J.S.; Zoology Department University College of RhodesiaSeven specimens of Protopterus from the Sabi Valley, Southern Rhodesia are described. Comparison with previous descriptions shows that these belong to the species P. annectens (Owen), of which a few specimens have been found previously in the Zambezi River Basin. It is likely that these specimens are from a population of P. annectens (Owen) which can be separated statistically by rib number from populations of P. annectens (Owen) in West Africa. The present specimens have rib numbers intermediate between those of P. annectens (Owen) from West Africa and P. amphibius (Peters) from Kenya and Tanganyika. The description of P. amphibius (Peters) from specimens collected at Quelimane on the Zambezi estuary has rested largely on differences in the number of ribs in comparison with specimens of P. annectens (Owen) from the same locality. Specimens of P. annectens (Owen) described here show that this distinction can no longer be maintained, and the possible occurrence of P. amphibius (Peters) as revised by Trewavas (1954) in the lower Zambezi and district must be regarded as uncertain. These fish present difficulties in subspecific taxonomy. Two groups of fish showing consistent differences in respect of a meristic character might be given subspecific rank.Item Mundulea Fish Poison(1936) Greenway, P.J.; Contribution from the East African Agricultural Research StationAttention has recently been drawn by Worsley to the insecticidal possibilities of Mundulea sericea (Willd.) Green way, comb. nov. The following is an account of its botany, ecology, distribution and recorded uses as a poison.Item Two New Hosts for Clinostomum Phalacrocoracis Dubois, 1931 (Trematoda), from Uganda(1970) Peirce, M.A.; Din, N.A.; East African Veterinary Research Organization, Muguga, P.O. Kabete, Kenya.; Scientific Warden, Queen Elizabeth National Park, UgandaClinostomum phalacrocoracis is recorded for the first time from Pelecanus onocrotalus and P. rufescens in Uganda. The incidence and intensity of infection, higher in the former species, are related to the feeding habits of the hosts. Although both species feed on Tilapia nilotica[Oreochromis niloticus], P. onocrotalus feeds on larger specimens which presumably harbour greater numbers of metacercariae.Item Some Preliminary Results Of Trap Fishing Trials For Crabs(1971) Heath, J.R.Preliminary results with a variety of traps indicate that madema are the most effective traps for catching Portunus pelagicus. No entirely satisfactory design has yet been produced for the Mangrove crab, Scylla serrata. A number of observations relevant to the fishery of both species have been recorded. Fishery of both species have been recorded.Item The Culture of Tilapia Nigra (Gunther) In Ponds Part Viii-The Effect of Cropping a Breeding Population by Trapping(1962) Vernon, D.In Part VI of this series the effect of selective cropping of a mixed breeding population of T. nigra in three different ways was described. In those experiments cropping was carried out by monthly seine netting with a t in. mesh nylon seine, and selection was effected by hand sorting the fish in one haul. The three methods employed were: (a) removal of all large fish, returning fry alive; (b) removal of only colored males, returning all females, immature males and fry alive; and (c) removal of fry only, returning all large fish alive. The results, which were different in each case, showed a profound effect on both the periodic crop taken and the final yield on draining.Item A Simple and Cheap Design of Large Reel for Commercial Bottom Fishing in Deep Water(1962) Morgans, J. F. C.Native fishermen of the coast do not use reels because most line fishing is done in a few fathoms of water with thick cotton line Now that mono filament plastic is becoming more favored this, too, is handled in the traditional manner. However, difficulties arise when powerful fishes are hooked for the thin plastic cuts hands severely and becomes uncontrollable, running out so fast that its coils usually snarl. A reel keeps the coils of line under control and obviates wear and tear on the hands. For both these reasons a reel is especially necessary when fishing deep.Item The River Fisheries of Kenya I-Nyanza Province(1959) Whitehead, P.J.P.An Investigation of the river fisheries of Nyanza Province has shown that there is a large and heavily exploited source of fish, the estimated annual yield of which exceeds 2,000 tons. The Kenya river fisheries as a whole may thus rival the marine fisheries in size. Preliminary findings, after a year of observations, were discussed in an Interim Report in which, however, it was stressed that further biological work was essential before accurate recommendations could be safely made. A second year of observation has now amply confirmed the initial overall impression, viz. increasing exploitation and, by excessive destruction of potential breeding stocks, a trend returns. Since such a situation parallels that found on Lake Victoria itself, it is not difficult to predict the final outcome on the rivers should conservation measures be delayed.Item A Study of a Small Basket-Trap River Fishery In Kenya(1959) Van Someren, D. V.An analysis is given of seven months' operation in 1957 of a small basket-trap fishery in the Ragati-Sagana river junction area, at an altitude of 3,940 feet in Kenya. The hydrological regime of the two rivers during this period is described, both rivers showing the twice yearly flood periods typical of most eastward flowing rivers in Kenya, with which are associated changes in conductivity and turbidity only three genera of fish enter such a fishery, two species of Anguilla, and one each of Barbus and Labeo. Though total catch showed a diminution in this period in spite of increased effort, this does not necessarily indicate a diminution of total stock available, since all these fish are migratory. Although the effect of fishing on total fish stocks is thus not clear over such a short period, the fishery appeared to alter the composition of the local fish stocks, Labeo dominance in early catches being replaced later by a Barbus dominance. It is suggested that this change may be due todifferences in the biology of the two genera, and data available from the trap catches concerning migration, food, sex ratio, maturity state and length /weight relationship are discussed. Studies on age and growth of these fish are not yet complete. The results have shown that such a small basket-trap fishery is relatively inefficient from a cash profit aspect, but it can nevertheless contribute materially on an individual subsistence basis to alleviating protein malnutrition, since the supply, though small, is fairly regularly obtainable at negligible cost in such rivers.Item Fishes taken by purse - seine and dip net in the Zanzibar channel(1966) Losse, G. F.Two commercial fisheries exploit the pelagic fishes in East African coastal waters. Both are confined to the Zanzibar Channel, a shallow water bank extending from the Pangani Estuary (Latitude 50 26' S.) in the north to Dar salaam (Latitude 60 49' S.) in the south. Asardine purse-seine fishery was introduced into this area by Greek fishermen during 1961(E.A.M.F.R.O. Annual Report 1961), laser tuna seining was developed (E.A.M.F.R.O. Annual Report 1963). Japanese dip nets, or boke ami, came into operation off Dar es Salaam in 1964.Both sardine seining and dip netting depend essentially on the attraction of pelagic fish shoals to a source of artificial light at night; the tuna seine exploits the larger surface shoaling species during the hours of daylightItem The dam fisheries of Tanzania(1966) Bailey,R. G.; Ministry of Agriculture, Forests and WildlifeDams constructed for domestic and agricultural purposes in Tanzania have been successfully stocked with fish. The geographical distribution of dams is discussed with some consideration of their physical, chemical and biological characteristics. The use of Tilapia in stocking dams is described together with the present distribution of these and other self-stocked species. A review of the fisheries exploitation of dams in Tanzania is made and a few estimates of the annual crops from dams are presented.Item Sharks of the Western Indian Ocean-II Triaenodon Obesus (Ruppell)(1960) Wheeler, J.F.G.; East African Marine Fisheries Research Organization, ZanzibarTriaellodoll obesus was first described by Riippell in 1835 (as Carcharias obesus) from specimens up to 3+ ft. in length (1,070 mm.) that he collected at Djetta on the Red Sea. It has since been recorded at a number of localities in the tropical Indian and Pacific Oceans, those of former including the Seychelles (Playfair, 1867), Madagascar (Sauvage, 1891), India (Day, 1889) and the Chagos Archipelago (Wheeler and Ommanney, 1953), but, curiously enough, it has not been observed until recently in Zanzibar or among the fishes of East Africa (Playfair and Gunther, 1866. Copley, 1952), nor does it range to the south far enough to be included among the fishes of southern Africa (Barnard, 1927, Smith, 1949).Item Sharks of the western Indian Ocean I - Loxodon macrorhinus M.& H.(1959) Wheeler, J.F.G.; East African Marine Fisheries Research Organization, ZanzibarThis paper is the first of a series intended to assist in the identification of the sharks of the East African coast, where many different species are caught but very little is known about them.Item The sea we fish in(1959) Morgans, J.F.C; East African Marine Fisheries Research Organization, ZanzibarMost of us realize that different forms of country such as savannah, swamp and forest, harbour different animals and that they move about or,perhaps, change their behaviour 3S their climate changes during the year. The same is true for fishes in the sea. Fishermen know that some sorts inhabit coral reefs, where as others are typically found over sandy bottoms and yet others in open water. But so far as the sea is concerned, little is known of the seasonal changes in the underwater climate off East Africa and of the effects of these changes on the fishes.Item Dagaa fisheries in lake Tanganyika(1954) Lockley, G. J.; Department of Agriculture, Tanganyika TerritoryThe dagaa industry of Lake Tanganyika is the Territory's most valuable inland fishery. The small sardine-like dagaa are marketed in a sun-dried form and this product is in great demand by employers of fed labour, particularly in the sisal industry. Over the past few years, sales of the value of exports of dried dagaa from the Lake Tanganyika area has been of the order of £150,000 per annum and approximately one-third of this amount is usually obtained in hard currency from sales to the neighboring Belgian Territories. On the production side the industry is entirely in the hands of Africans and at least 6,000, using upwards of 2,000 canoes, are believed to be engaged in the fishery.Item Fishery research in the lakes of East Africa(1954) Beauchamp, R. S. A.; East African Fisheries Research Organization, UgandaFishery research is the study of fish in relation to their environment; little can be learnt about them until we have a fair knowledge of the conditions in which they live. The need for this knowledge is made very obvious to the biologist working on inland fisheries. Forxample,the same species of fish occur in anumber of East African lakes, in some theygrow to a considerable size. weighing several pounds, while in others they never exceed afew ounces in weight. No explanation of these facts is likely to arise from investigations confined solely to the study of the fish themselvesItem The families of freshwater fishes of Tanganyika Territory, with a key to their identification(1949) Lockley, G. J ; Department of Agriculture, TanganyikaEvery specimen should be accompanied by a label giving details of locality, altitude, date, method of capture, sex (if known) and any other relevant items such as the colour of the fish in life. Such labels are best written on unsized paper with a 2B pencil or on parchment paper with waterproof Indian ink.Item A study of the fecundity of some mormyrid fishes from lake Victoria(1970) Okedi, J.; East African Freshwater Fisheries Research Organization, Jinja, UgandaThe need for a rational exploitation of the fish stocks in the Lake Victoria Basin has, during recent years, necessitated further investigation of the breeding potential of the species of commercial importance. Because of their greater commercial importance in East Africa, the fecundity of species belonging to the families Cichlidae and Cyprinidae is better known than that of the Mormyridae. Lowe (1955) has described the breeding potential of a number of Tilapia and Cadwalladr (1965) has published some notes on fecundity in the cyprinid fish, Labeo victorianus Boulenger.The only available reference to fecundity in the Mormyridae, is that of Nawar (1959b), who made some observations on Hyperopisus bebe Lacepede from the Nile. Although members of the Mormyridae at present make up a relatively small part of the total landings offish from Lake Victoria, the group is nevertheless becoming one of increasing commercial importance to the fishery of the affluent rivers, Okedi (1966).
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