The Government of Nigeria, assisted by the United Nations Development Programme and the Food and Agriculture Organization of the United Nations has been engaged on a project concerned with research in the Kainji man made lake.
The purpose of the Kainji Lake Research Project was to assist in the comprehensive development of man made lake resources through research and surveys. Research was conducted in the fisheries, agricultural and socio-economic aspects. It also studied Public Health problems and means of developing the Borgu Game Reserve into a national tourist attraction.
The long range objective of the project as far as fisheries is concerned is described as follows:
”To establish a fishery research programme that will enable the fullest utilization of the lake's and downstream river's fish crop on a maximum sustained yield basis. This will require limnological and biological research, also trials and demonstrations of new fishing boats, different fish catching, processing and marketing methods.“
The project became operational on 12 August 1968 and terminated on 31 August 1974.
As part of the project operation, FAO assigned a consultant; his original terms of reference were to study the present fish processing methods around the newly created Kainji Lake basin in order to assess the possibilities for improvements and to outline a future research programme to be incorporated in the project at a later date.
The project will shortly become a Federal Institute of which the results will be made available to all states requiring assistance in the fields covered by it.
The consultant arrived in Nigeria on 10 January 1974 and left on 5 March 1974. In this period a meeting of the fisheries subcommittee of the National Advisory Committee of the project was attended at Ibadan.
At this meeting the consultant was asked to consider covering a few more points outside the actual terms of reference.
Survey of existing fish processing technology and suggestions on ways to improve these;
construct smoking kilns of improved design using local cheap materials, smoking trials for brined and unbrined fish;
experiments on salting and sundrying of larger types of fishes, e.g. Tilapia and Lates;
sun drying of clupeids - comparative trials of fish drying on wire mesh racks and on cement floors. Protection from rain. Estimation of conversion ratio for commercially dried clupeids. Packaging and storage;
training of project's staff on handling, processing, packaging and estimation of quality grades of fresh fish. Train staff on how to ice fish in fish boxes for transportation to inland markets.
Due to a lack of locally available material point 2) has been covered only as far as construction of a kiln. Due to the absence of water for several weeks at the project site it was not possible to handle fish in the proper way or to produce ice on the scale required.
Information with regard to quality assessment of fresh fish and icing of fish was given to Mr. A. Illoh, B.Sc. (studying biochemistry in Ife University) who for the duration of his service in the National Youth Corps was assigned to the Kainji Lake Research Project, and assisted the consultant during his stay at Kainji. He undertook a preliminary survey of the fish processing methods around the lake.
Mr. Illoh, if given the necessary equipment might give further help in carrying out the research required into the existing local traditional and new processing methods as outlined in this report.
The consultant would be willing to assist a future research programme with suggestions, literature, information about equipment and if so required act as a liaison between the project and other institutions or companies.
The Kainji Lake is located in the western part of Nigeria and is in fact a part of the Niger River system. It was created in 1968 on the completion of the Kainji Dam and covers an area of 1 280 km2 when at its highest level.
The primary purpose of the dam is of course the production of electricity for the country. Other possible benefits however are improved navigational facilities downstream of the dam and on the lake up to Yelwa, introduction of irrigation schemes and (it is hoped) increased fish production.
The fish production off the lake in the first years after its impoundment, due to a high content of nutrients in the water, seems to have been as high as an (estimated) 27 000 tons per year, but in the meantime has dropped sharply to a figure below 10 000 tons per year.
It is not yet quite clear whether this decline is due to the gradual leaching of the inundated lake shores or to better sampling methods or to both.
It seems to be clear that the water of the River Niger and its tributaries outside and inside Nigeria are of relatively low nutrient content.
Important
fishing villages around the lake are:
Yelwa,
Papiri, Shagunu, Rofia, Wara, Doro, Garafini, Duga.
According to a 1970 estimate no less than 7 163 fishermen using 3 961 canoes are operating on the lake.
A large proportion of these are non-indigenous fishermen from the south, mid-west and from Lake Chad who have been attracted by the supposedly high production of the lake. How far the decline in catches has caused the quoted figure to drop to a lower level is not known.
Canoes are both dug out and planked. The amount of mechanisation seems to be low. Canoe craft are too unstable to fish deeper waters in the lake and to reach such grounds only after a long time of paddling must discourage fishermen to even try fishing in deeper water. Fishing is therefore confined to the shallower parts of the lake near the shores and in the numerous creeks and swamp areas that have been created since the impoundment of the lake.
Fishermen do not necessarily operate from their home village only. Many, in fact, move to temporary fishing camps when the fishing is good. Most of these camps of course have no other connexions with villages and trading centres other than via water transport.
Consequently all the fish that is not used for home consumption has to be preserved.
Fishing gear in use are gill nets of various sizes and mesh. The use of synthetic materials is well established. Apart from gill nets many fishermen use long lines to catch fish. A variety of fish traps in all shapes and sizes can also be found around the lake.
A large variety of different species is being caught in the lake. The most important of these from a commercial point of view, that is looking at their presence in the dried fish trade seem to be the following:
Latin name | English name |
Synodontis spp. | Cat fish |
Lates | Niger perch |
Citharinus | Moon fish |
Bagrus spp. | Cat fish |
Tilapia spp. | - |
Schilbe spp. | Butter fish |
Clupeid spp. | - |
The fishing knows marked good and poor seasons, with highest catches in the June–July–August period and lowest catches in the January–February–March period. The period of high catches coincides more or less with the rainy season when possibilities for processing, most of all for sun drying are most unfavourable.
Climatic conditions in the Kainji Lake basin are those of a savannah. The period April to October is characterized by a southern wind coming from the ocean and bringing rain. The period November to April brings the hot dust-laden dry northern wind from the Sahara (Harmattan).
The temperature and relative humidity for Yelwa at the northern end of the lake are given in the table below.
Temperatures at Yelwa
Period | Jan. | Feb. | March | April | May | June | July | Aug. | Sept. | Oct. | Nov. | Dec. | Av. Year |
1951–1961 Mean Max. | 96.5 | 99.8 | 100.3 | 100.8 | 94.9 | 90.3 | 86.6 | 85.5 | 87.1 | 91.1 | 97.0 | 95.9 | 94.0 |
1951–1961 Mean Min. | 59.2 | 64.3 | 74.5 | 78.4 | 76.5 | 73.7 | 72.1 | 71.9 | 71.1 | 70.6 | 62.7 | 57.3 | 69.4 |
Relative humidity at Yelwa
Period | Jan. | Feb. | March | April | Hay | June | July | Aug. | Sept. | Oct. | Nov. | Dec. | Av. Year | |
1951–1960 | Mean at 07.00 | 59 | 49 | 59 | 69 | 81 | 89 | 93 | 95 | 95 | 95 | 91 | 76 | 79 |
" | Mean at 16.00 | 16 | 15 | 22 | 32 | 49 | 59 | 67 | 70 | 67 | 56 | 29 | 19 | 42 |
(Figures taken from Jenness, 1970, Fishermen of the Kainji Basin, Informal Rep: No. 3) |
The time elapsing between lifting of the nets and delivery to the shore can vary with the distance that has to be covered. It can at times be a period of several hours.
The fish, when brought aboard is usually more or less alive. It is stored simply on the bottom of the canoe, lying there in a pool of warm, dirty water. The fish is never gutted and freely exposed to the sun.
Needless to say the product thus handled has an extremely short keeping period that could be improved by more hygienic handling and by keeping the fish in shade. The ultimate aim at least for the fish to be entered into the fresh fish trade should of course be to have the fish iced.
The same applies to the handling after landing. No precautions are taken to prevent the fish from being covered with sand, leaves, sticks, etc. Better handling practices would be a prerequisite to the development of a fresh fish export trade towards the larger towns in the north and south.
It is a well known fact that fishes' rigor mortis period lasts longest with fish kept at a low temperature and is also favourably influenced by killing the fish as soon as possible after catching; in other words by shortening its death struggle and avoiding chemical and enzymic deterioration after passing the rigor mortis period at the lowest possible level.
It is recommended that future research tries to establish whether the relationship between killing the fish right after landing on board and a consequent extension of the rigor mortis period is of sufficient significance to be taken up in a programme of improvement of fish handling.
An estimated amount of 90–95 percent of the total fish catch is being processed into dried fish. All the fish, except the clupeids, for drying are exposed to the heat and smoke of burning wood.
The general consumer's preference, established during many preceding decades, is clearly for unsalted dried fish with a fairly heavy smoke taste in the ease of the indigenous species of fish. Before 1966 however, Nigeria on average also imported 30 000 tons of stock fish, a non smoke flavoured product, yearly. This import trade was reintroduced in 1973 for a short period but stopped again due to price increases.
Salting or brining as a preliminary treatment prior to drying is not being used. Fish from Lake Chad however, according to information, is being salted and sun dried. It seems therefore likely that a market for the salted product exists somewhere in or outside Nigeria.
The consequence of the non use of salt is that the fish, at least during the initial stages of drying, must be preserved in another way to prevent spoilage during drying. This is being achieved by subjecting the fish, at least during the first hours of the drying process to high temperatures. The resulting cooking of the fish to some extent sterilizes the fish, stops the activity of enzymes in the tissue and intestines, and frees part of the moisture in the fish that hereafter dries more quickly.
The fact that such fish after prolonged drying becomes a very brittle product that needs only little pressure or bending to break and crumble into smaller pieces does not seem to affect either producers or traders very much. Nevertheless the loss both in weight and quality (and value per piece) must be considerable.
Other authors have estimated the total losses as high as 15 percent.
The smoking process is carried out in simple smoking ovens of different outward appearance, usually constructed of mud. The oven invariably contains one single support to lay fish on during drying and smoking. This support usually is made out of a piece of expanded metal or out of a steel rod frame with chicken wire. The support is either taken up into the structure or in turn supported by steel rods embedded in the walls of the oven.
Ovens are to be found of all sorts of shape and sizes. The most common model consists of walls either in oval shape or rectangular (Fig. 1).
The rectangular ones are sometimes grouped together to larger units of three or more. At one occasion an oven was seen constructed of wooden poles at the corners, covered with thin metal sheeting to form the walls. The owner claimed that he bad no preference for either the mud or metal oven. Most processors however are keenly aware of the better heat retaining properties of the thick earthen walls as compared with the metal.
To keep as much of the heat as is possible in the drying oven it is covered with a thin sheet of metal, usually flattened pieces of corrugated roofing material. The irregular shape of these, their battered appearance and the fact that mostly they were torn in various places makes the effectiveness of this method far less than what could be regarded as a possible maximum. The cover of the kiln, can, with a bit of fantasy, be regarded as a roof with a rather unctrollable air outlet. The drying ovens in their present shape make it difficult to put more than one drying rack in the kiln, as is done for example in the Altona oven (as described in FAO report FIIP/T 104 entitled "Equipment and Methods for Improving Smoking and Drying of Fish in the Tropics). It could be done by having an additional loose drying rack fitting into the kiln and kept at a distance from the underlying supporting rack by metal legs or even by a few bricks. Processors however, when asked whether they never considered this possibility, answered that the work involved in exchanging the positions of the fish relative to the fire would be too much and also expressed the fear that fish in the top layer would not receive sufficient heat if the bottom layer was tightly packed.
Provided that the bottom layer or successive layers are not so tightly packed, so that hot air can reach higher layers and with a slightly changed kiln design, a better fuel to fish weight ratio can be achieved and better process control comes within reach. One such kiln was shown to the expert at the fisheries office in Yelwa in the north western State. This kiln, constructed in a few days on the occasion of the state visit of the Head of State, was made of mud walls and was provided with a mud roof supported by sheet metal. Air outlet is through a number of holes in the top of the side walls. Inside are three drying racks that can be taken out (Fig. 2).
The author is of the opinion that trials with this oven deserve much attention, since it can be made with the simplest and cheapest materials.
A similar one should be constructed at the Kainji site to obtain experience before starting demonstrations in the field. It would in the author's opinion however have to be provided with a small chimney with damper to obtain better process control.
In the more northern parts of the Kainji Lake basin the kilns are of a different shape that can be described as an hour glass. A reason for this particular shape could be that the top part of this type of kiln fits more or less around the open top half round baskets in which the fish is kept after smoking and drying, thus facilitating easy re-drying (Pig. 3).
It could also be that the venturi shaped upper part of the oven gives a better distribution of the hot air over the surface on which the fish is exposed to it and thus gives better process control, reduced necessity to change the position of the fish and possibly better fuel economy than is the case with the rectangular oven. It might be worth while to pursue this point in future research.
All fishes, except the smallest ones, prior to smoking are gutted and scales are removed. If water is readily available fishes are then washed to remove dirt and slime. The larger fishes such as catfishes are curled around so that the tail reaches the head and then either skewered on a pointed stick or the tail is fixed on the fish's own pectoral spine as is the case with Synodontis. The reason for this practice seems to be the resulting reduction of material losses through breakage after drying and during transport.
Small and medium sized fishes in an operation prior to subsequent smoking and drying are sometimes laid out on a bed of dry burning grass and left there in the smouldering ashes until transferred to the smoking oven to be dried further over a slow burning fire. This charring method, although crude and giving the product an unsightly dirty and blackish appearance is again probably for fuel saving and is most effective in that it quickly destroys the spoilage mechanisms on and in the fish. Very large fishes such as Niger Perch are cut into smaller, more easily handled and dried pieces of approximately 1 kg. These large pieces before processing are often wrapped in pieces of discarded netting material to prevent them from falling apart during processing and subsequent storage and transport.
The processing in the smoking ovens consists of a period of several hours in which the fish is cooked followed by a period of drying with a low slow burning fire, producing only a moderate amount of smoke. The length of this latter period varies with the required keeping quality. :Fish to be sold within a few days for local consumption or for nearby markets may be smoked for 24 hours, fish for export to the south may be dried for as long as four or five days. The smoking period is probably also influenced by the market cycle. The moisture content of the dried product varies thus between an estimated 40 percent in the higher ranges and 10–20 percent in the lower.
In one experiment the author bought fish from the local tradeswomen at Faku and had this lot smoked by a local processor in the traditional method. Particulars of this trial are given.
gr. | |
Weight of purchased fresh fish | 8 310 |
" dressed fish prior to smoking | 8 045 |
" smoked fish after 24 hrs smoking | 3 640 |
" " " " 48 " " | 1 780 |
" " " " 72 " " | 1 655 |
Percent | |
Weight loss after dressing in percent fresh weight | 3.2 |
" " " 24 hrs smoking | 55 |
" " " 48 " " | 65.8 * |
" " " 72 " " | 80 |
* The fish after this period was judged as being sufficiently dry to be marketed.
It is recommended that more similar trials be carried out in the field, preferably with a full load of the kilns, to obtain a reliable figure on the average weight losses during the smoking process. In the above experiment the amount of fuel used was also recorded as 66 kg. It should be realised however that a far larger amount of fish could be smoked with this quantity of hard wood if the oven were loaded to its maximum capacity. the product when ready for sale is brought to market in open top round baskets, mostly by fishermen's wives who have processed the fish. At the market the fish is sold per basket, usually to male fish traders who combine their buyings to larger expert lots. The quality of the product, judged on degree of drying, appearance, damage and insect infestation is influencing the price. The weight of an offered lot of fish is judged superficially by lifting the baskets. The wholesale fish traders usually assort the fish to species and size and pack these in a cylindrical basket known as mankara, made of Guinea corn stalks. The inside of such baskets is padded with paper. Used cement bags are used for this purpose. The net weight of such a mankara according to Anthonio (see bibliography) may vary between approximately 30 kg and 60 kg. According to data being compiled at the Yelwa fish market the gross weight of mankaras with dried fish varies from 15 to 25 kg. A large empty mankara would cost up to 60 kobo (US $ 1). As a packaging entirely made of local readily available material the mankara is certainly cheap and reasonably effective in giving protection against mechanical damage. Protection against insect infestation during transport and storage is of course hardly a quality of the mankara. An improved way of packaging, giving better protection against insect infestation would have to be a well closing box with the disadvantage, contrary to the mankara, that it would be too costly to be treated as a one way package, as is the case with the mankaras, which would cause a doubling of the transport costs and an elaborate system of deposits on packaging.
A reduction in losses of produce through breakage and insect infestation, would in the opinion of the consultant have to be found in the gradual introduction of a salted dried product that is less attractive to insects and that can contain a higher percentage of water, thus being less susceptible to breakage.
Such a salted product however requires different methods of preparation and cooking. It is again in Yelwa that some experience with a salted, sundried product is being obtained.
The findings of the home economists of the north western state in this respect would be useful in setting up marketing tests for this sort of product.
The prices of fresh fish and smoked fish seem to vary through the season with supply and demand and depend also very much on the location and the fishermen's or trader's need of money.
In the short term of this study it has not been possible to collect data of sufficient reliability in this respect. The concensus of opinion seems to be that fishermen prefer to sell their produce fresh, in the first place because they prefer not to be bothered with the job of fish smoking but also because generally a fresh fish fetches a higher price than a dried fish (on a piece basis), in those places where a substantial demand for fish exists, i.e. villages and towns.
The lack of fast transport forces the fisherman in the remote areas however to take up processing himself (or his family) or to sell his fish at rock bottom prices to professional processors.
The profit margin in the processing operation is another mystery that would need clarification. Anthonio in his report (p. 69) comes to the conclusion that the price of dried smoked fish (per lb) on average is 256 percent higher than of the fresh fish (per lb) and concludes that smoking is a very profitable operation. If one considers however the incurred weight loss of an average 55 percent and the costs of smoking (labour, firewood, etc.) the profit on smoking appears to be negative (Appendix 2).
In view of comparisons to be made between the costs of adapted or new processing methods (such as the use of ice and salt) and the traditional processing it would seem a very useful effort to renew and update the data on the price structure of the fresh fish intended for smoking, fresh fish intended for fresh consumption and processed fish, over a period covering at least the good and the poor fishing season.
If it were found true that the profits on smoking and drying are very small or negative the fact remains that the non-fishing professional processors must be making a profit large enough to pay for their labour and risks.
The conclusion could be that they are doing this only by buying fish at lower than normal prices in remote areas and that the profit is merely a remuneration for input of labour for which in fact the fishermen are paying.
Under such circumstances there seems to be a case to induce the fishermen to take up their own processing for example in cooperatives and to stimulate better distribution facilities for fresh iced fish.
In this respect it would also be useful to obtain an idea how much wood is used yearly to preserve the catches of freshwater fishes. On the basis of the combustion value of dry wood, approximately 3 000 kcal/kg, an assumed weight loss of fish of 60 percent during drying and for this type of dryer an evaporation heat for the water of 2 500 kcal/kg, it can be calculated that per kg fresh fish to be smoked and dried, an amount of
For the whole of Kainji Lake where an estimated amount of 5 000 tons of fish is processed during the year, this theoretical figure would mean a consumption of wood of 2.5 million kg, an impressive figure in an area where deforestation and slow creeping drought are imminent dangers and in itself a reason to stimulate alternative processing and handling methods even at the expense of government subsidies on better infrastructure, reduction of taxes on salt used in fisheries and mineral fuel used in stationary (drying) plants and power plants.
Piatek in 1963 did a number of experiments comparing local ovens (smoking Bonga), Tanganyika ovens and Altona type ovens (pp. 20, 21) and found appreciable fuel savings in the range of 30 percent for the Altona type oven provided the fish are hung on sticks. For the traditional oven Piatek quotes a figure of 3.16 m3 wood per ton of fish (fresh weight) which seems not to correlate with the theoretically derived figure above. This leads to the conclusion that efficiency of the traditional ovens and processing methods is extremely low.
The Altona type oven consumes 2 m of wood per ton of fish, still a figure that is not impressive from the efficiency point of view.
(It would be an interesting exercise to assess the amount of fuel wood used in domestic cooking and compare this figure with the amount of wood used for fish smoking).
A special case is presented by the Clupeid spp. (Sierrathrissa leonensis and Pellanuloa afzeliusi). These very small fishes with an average weight of approximately 0.26 g, because of their small size can only be processed in bulk and so far were only sun-dried (the only sun-dried fish product around the lake). A substantial amount is being caught by dip nets, mainly in the northern narrow end of the lake and brought to Yelwa fish market.
Until recently the total stock of Clupeids in the lake was believed to be in the range of 160 tons (Lelek). The fisheries technologist of the project however, with pelagic trawling trials has proved that much more than this quantity is available. The expectations for Clupeids are now, pending a survey covering the whole lake, set at around 10 000 tons sustainable yield per year.
The Clupeids, because of their very small size, are an easily drying product. The fish can in about 24 hours (including the nightly hours) lose as much as 75 percent weight. The drying speed on (mosquito) screens is only marginally faster than on solid surfaces. Further drying of the product in a drying oven at 100°C reduces the weight to almost exactly 20 percent of the fresh weight. There seems to be no reason to change anything in the present sun drying method, apart from letting people know that the fishes should be spread thinly, preferably not more than one fish thickness, while drying (2.8kg per m).
This necessity of spreading the fish very thinly and the consequently large required surface for drying is reason for the author to discard the idea of artificial drying of the fish in mechanical drying kilns.
A good drying method for Clupeids was seen at Faku. The fish are spread on mosquito screening that in turn is resting on a bed of dried grass. The high drying rate of the Clupeids eliminates the danger of insect infestation during drying. Clupeids when dried are packed in large bags of synthetic material, sometimes woven, sometimes polyethylene film. This material offers some protection against insect infestation during storage. However, cockroaches seem to penetrate fairly easily through these materials.
Nevertheless, if trawling with harvests of more than 100 kg/hr continues to be successful, some form of bulk processing must be introduced. Since the dried Clupeids before use in meals are being ground to a powder (in other words reduced to fish meal) the logical line of thought is directed to fish meal. The smallest available fish meal units on the market are machines with a capacity of 10 tons/24 hrs or 2 500 tons per year 1.
At the present price of the locally caught Clupeids, about 6 kobo (10 US cts) per kg, one cannot of course expect to produce ordinary fish meal for animal consumption in competition with the international market and in view of the relatively small quantities concerned such a venture would not seem a realistic one to pursue. Besides there is a strong feeling among the authorities concerned that good fish protein should not be wasted in animal food.
It would however be perfectly feasible to produce a good hygienic fish powder in the same way, that can be sold on the markets as a ground dried Clupeid and that altogether falls in a different price bracket when regarded as human food. It could also be tried if a simple batch drying process in a rotating drying drum would be sufficiently effective in drying the Clupeids to the required moisture content.
The fresh Clupeids locally are highly relished food after frying the fish in oil. One of the members of the National Advisory Council when at Kainji Research project took frozen Clupeids to Lagos for home consumption and would in fact be willing to buy on a regular basis if available in Lagos. This might also be a line to pursue if refrigerated transport to Lagos could be organized.
The nearest freezing plant cum cold store with regular transport to Lagos is that of the Mokwa Cattle Scheme at 120 km from Kainji. Provided that well frozen and packed fish are supplied they would probably be willing to help in sending some trial shipments of frozen Clupeids (and other fish) to Lagos or Ibadan. (A 10 kg frozen sample was prepared at the project to be sent to Ilorin for test marketing).
The project for this purpose would have to obtain freezer equipment and cold storage. Some information regarding the costs of this equipment is given elsewhere in the report (Appendix 1).
The next possibility for use of Clupeids that in the author's opinion would be worth while trying out is the production of Asian type fish sauces and pastes, like the Nuoc-Mam of Thailand and the Pindang from Indonesia. In the Nuoc-Mam process the fish, mixed with salt, is left to decompose under the influence of enzymes of the ungutted fish itself. After several months a clear supernatant solution of amino acids is obtained. The Nuoc-Mam naturally very salty, is used as a condiment to foods rather than as food proper. Literature on this Subject is available and should be obtained for the project. A Nuoc-Mam is already produced in Abidjan, Ivory Coast, by Finuma S.A.
It would also be worthwhile trying to develop salted Clupeids, stored and transported under brine. This product would be produced by dry salting the fish with 20 percent salt and keeping the fish under the developing brine in, for example, plastic barrels with lids. Such a product for consumption would have to be soaked for a period and could then be fried as a snack with either drinks or meals.
As a raw material for canning, the Clupeids are unsuitable. The small size of the fish would necessitate a cannery to use the fish with heads. The sterilization process, as was found in a simulated “canning” experiment does not sufficiently soften the bones of the head with the result that the product obtains an unpleasant gritty structure. The conclusion must be that canning of Clupeids is not feasible.
Another altogether new product that could possibly be produced in the starch (cassava) consuming areas of the country is the Indonesian “krupuk”. In the manufacture of krupuk an amount of fish fillet is finely minced and mixed with double the quantity of cassava starch, water and if required salt, sugar and spices. This mass is kneaded to a dough-like consistency, wrapped in a clean cloth and then cooked over steam for several hours. The cooking time depends on the dimensions of the “bread”. The cooked “bread” is left to cool overnight and then cut to thin slices that are being dried in the sun. The dried slices for consumption have to be fried in oil and expand to at least twice the original size, producing a very palatable product that can be used as a snack with meals or drinks. The product can also be pre-fried and sold as such. The production method is simple and requires very little equipment apart from a meat mincer and (but not absolutely necessary) a kneading machine. It could easily become a sort of house industry.
To establish a modestly equipped experimental demonstration centre at the future Institute at Kainji in order to carry out among other things, the following programme:
A study of the effect of gutting and bleeding fish on board immediately after hauling, on keeping quality. This would be particularly relevant if a chilled fish export trade from the Kainji area to other towns of Nigeria were to be developed.
A study of the production and acceptance tests of dried salted fish. The acceptability level of salt concentration in the products should be established and the required amount of drying to obtain good keeping quality determined.
In view of a possible over-exploitation of forests to study the fuel wood consumption of different types of smoking kilns and procedures. To establish also the actual or capitalized costs of the fuel used per unit weight of fish in order to decide whether replacement of wood by mineral fuel would be an economic proposition.
To construct an improved traditional mud kiln of the type seen at Yelwa and an Altona type kiln and to study their performance.
To collect data on:
the price at different trade levels of fresh and dried fish
the transport costs of fish to markets outside the area.
and on the basis of these to decide whether a pilot scheme for the collection of chilled fish and distribution to larger consuming centres would be a feasible proposition. If found feasible such a pilot scheme should be implemented.
In view of the fact that Clupeid spp. may be expected to become a major part of the catches of Lake Kainji:
to test market powdered dried Clupeids and to decide whether or not to embark on bulk drying operations
to study the possibilities of large scale production of new products like krupuk and fish sauces.
In view of a programme to cut down losses by alternative processing and packaging methods to study the losses in weight and value of dried fish during transport and storage.
General Recommendations
A complete and sophisticated fish processing research department should not be set up at Kainji Lake during the initial stages of the programme, but the required period would fit into a well defined five-year plan under which staffing would be as follows:
One Food Technologist - assisted by
Two Field Assistants with high school education and some experience of inland water fisheries
One Chemical Analyst.
At a later date, the programme would also require the part time cooperation of a chemist and an economist (each for approximately six man-months). This team in total would spend nine man-years in the two-year period envisaged, three academic man-years and six analyst assistant man-years.
A chemist could be recruited from or seconded by the Federal Fisheries Research Institute in Lagos.
The programme envisaged for Kainji would eventually develop into a mere demonstration and extension centre for the Kainji Lake Basin and possibly also for other inland fisheries. Whenever more sophisticated research, such as analysis of amino acids and spoilage products is required, such research could be done at university laboratories or at the Federal Fisheries Institute at Lagos where both the expertise and more favourable working conditions are available.