APPENDIX A
AGENDA

Agenda item

1. Opening of the Session

2. Election of Chairman, Vice-Chairman and Rapporteur

3. Review of state of stocks and fisheries of Lake Victoria

4. Consideration of report and conclusions of HEST/TAFIRI/FAO/DANIDA regional seminar on fish stocks and fisheries in Lake Victoria

5. Socio-economic issues for planning in support of fisheries management

6. Priorities for research and management in Lake Victoria

7. Adoption of the report

APPENDIX B
LIST OF DELEGATES AND OBSERVERS

Members of the Sub-Committee

Kenya

ARUNGA, O.J.
Assistant Director of Fisheries
Ministry of Regional Development
P.O. Box 1084
Kisumu

OGARI, J.J.
Senior Research Officer
Kenya Marine and Fisheries Research Institute
P.O. Box 1881
Kisumu

DOLA T.
Project Coordinator
Lake Basin Development Authority
P.O. Box 1516
Kisumu

Uganda

ORACH-MEZA, F.
Deputy Commissioner for Fisheries
P.O. Box 4
Entebbe

KUDHONGANIA, A.W.
Director of Research
Uganda Freshwater Fisheries Research Organization
P.O. Box 343
Jinja

ACERE, T.O.
Senior Research Officer
Uganda Freshwater Fisheries Research Organization
P.O. Box 343
Jinja

BUGENYI, F.
Limnologist
Uganda Freshwater Fisheries Research Organization
P.O. Box 343
Jinja

KARUHANGA, P.N.
Research Officer
Uganda Freshwater Fisheries Research Organization
P.O. Box 343 Jinja

Tanzania

SICHONE, W.A.M.
Director of Fisheries
P.O. Box 2462
Dar es Salaam

MAPUNDA, R.R.
Principal
Nyegezi Fisheries Training Institute
P.O. Box 1213
Mwanza

BWATHONDI, P.O.J.
Director General
Tanzania Fisheries Research Institute
P.O. Box 9750
Dar es Salaam

YONAZI, J.
Liaison Officer
Fisheries Division
P.O. Box 2462
Dar es Salaam

KATONDA, K.I.
Centre Director - Kigoma
P.O. Box 90
Kigoma

MKUMBO, O.
Research Officer
TAFIRI
P.O. Box 475
Mwanza

TEMU, M.
Research Officer
TAFIRI
P.O. Box 475
Mwanza

SENKORO, K.
Research Officer
TAFIRI
P.O. Box 475
Mwanza

BUDEBA, Y.
Research Officer
TAFIRI
P.O. Box 475
Mwanza

KILOSA, E.
Regional Fisheries Officer - Mara
P.O. Box 299
Musoma

RUSHOKE, E.
Regional Fisheries Officer - Kagera
P.O. Box 671
Bukoba

MWAIBULA, D.
District Natural Resources Officer - Ukerewe
P.O. Box 139
Nansio, Ukerewe

KAYUNGI, J.
Tutor
Nyegezi Fisheries Training Institute
P.O. Box 1213
Mwanza

MWAMBUNGU, J.
Research Officer
TAFIRI
P.O. Shirati
Tarime - Musoma

MSUKU, B.
Research Officer
TAFIRI
P.O. Shirati
Tarime - Musoma

MATOLAH, P.F.
Pasiansi Boatyard Project
P.O. Box 1577
Mwanza

Observers from Intergovernmental Organizations

East African Development Bank

GATERE, K.
East African Development Bank
EADB Building
4 Nile Avenue
P.O. Box 7128
Kampala
Uganda

Haplochromis Ecology Survey Team (HEST)

LIGTVOET, W.
P.O. Box 903
Mwanza
Tanzania

MOUS, P.J.
P.O. Box 903
Mwanza
Tanzania

EEC Naval Architect

MAC ALISTER, R.
Mac Alister Elliott and Partners
56 Highest Lymington
Hants 504190H
UK

The Netherlands

VAN DENSEN, W.L.T.
Lecturer
Agricultural University
Wageningen
The Netherlands

FAO Fisheries Department

FAO
Via delle Terme di Caracalla
00100 Rome

WELCOMME, R.L.
Chief
Inland Water Resources and Aquaculture Service
Fishery Resources and Environment Division

Field Staff

GREBOVAL, D.
Inland Fisheries Planning, Development and Management in Eastern/Central/Southern Africa
c/o FAO Representative
P.O. Box 1250
Bujumbura
Burundi

SSENTONGO, G.W.
Inland Fisheries Planning, Development and Management in Eastern/Central/Southern Africa
c/o FAO Representative
P.O. Box 1250
Bujumbura
Burundi

LUCIA, D.
Programming Officer
FAO Office
P.O. Box 2
Dar es Salaam
Tanzania

REYNOLDS, E.J.
Uganda Fisheries Statistics and Information System
FAO Office 1
P.O. Box 521
Kampala
Uganda

CHAKRABORTY, D.
Team Leader
URT/87/016 Statistics Project
Fisheries Division
P.O. Box 2462
Dar es Salaam

Secretariat

Host Government

MULEGI, Z.
Chairman of Liaison Committee
Regional Natural Resources Officer
P.O. Box 200
Mwanza

NKAKA, E.
Manager
Mwanza Boat Yard
P.O. Box 6384
Mwanza

KATUNZI, E.
Centre Director - Mwanza
TAFIRI
P.O. Box 475
Mwanza

MTOLELA, J.
Regional Fisheries Officer
P.O. Box 226
Mwanza

BYARUCABA, C.
Meeting Assistant
Tutor
Nyegezi Fisheries Training Institute
P.O. Box 1213
Mwanza

MAHATANE, A.
Assistant Liaison Officer
Tutor
Nyegezi Fisheries Training Institute
P.O. Box 1213
Mwanza

BYARUGABA, E.
Secretary
TAFIRI
P.O. Box 475
Mwanza

MBARAKA, H.
Secretary
Nyegezi Fisheries Training Institute
P.O. Box 1213
Mwanza

FAO

WELCOMME, R.L.
Technical Secretary of the Sub-Committee

APPENDIX C
LIST OF DOCUMENTS

APPENDIX D
NATIONAL REPORTS

1. The Uganda Waters of Lake Victoria - Uganda

2. The State of Lake Victoria Fisheries, Kenya Waters

3. The State of Lake Victoria Fisheries, Tanzanian Sector

APPENDIX D.1
THE UGANDA WATERS OF LAKE VICTORIA

by

E.S. Kanyike
Deputy Commissioner for Fisheries
P.O. Box 4
Entebbe, Uganda

STATUS OF THE FISHERIES

The Uganda waters of Lake Victoria are becoming more important in their contribution to the national catch (about 49 percent). This has been mainly due to species which were introduced form the western lakes (Lates niloticus, Oreochromis niloticus, Oreochromis leucostictus and Tilapia zillii). Considering the present catch of 107 092 t for 1988 the Nile perch (Lates niloticus) formed 85.9 percent of the total catch from the lake.

The domination of the catch by Nile perch has been due to the use of large mesh size gillnets ranging between 6 to 12 inch. Fishermen need not go far to fish for Nile perch in many areas, which means that they spend less money on fuel. whereas in the case of species like Bagrus docmac, fishermen need to travel considerable distances to the fishing grounds. This has lead to a drop in the catch of bagrus and the impression that this species has disappeared.

Recently the exploitation of Rastrineobola argentea (Mukene) has also increased. This is a species which is caught using light fishing and is used in the manufacture of animal feeds and for direct human consumption. This species was virtually unknown in catches previously, but has recently become available for human consumption in Uganda.

The Nile perch has had a great effect on the catch composition from the lake and as a result other species have become more expensive if they are caught. Species like Synodontis sp. which is so difficult to remove from nets, is no longer of any interest to the fishermen. Thus composition of the catch does not actually tell us what is in the lake. The forthcoming Lake Victoria Fisheries Research project should give us the actual picture of the present status of the stocks of the fishery of Lake Victoria. The results from this research will give us the management strategies of the lake as well.

Underutilized Species

The fauna of Lake Victoria provides opportunities for further utilization. There are bivalves, gastropods, crabs, lake flies, etc., which are hardly used. In Uganda the bivalves and crabs are only used as bait. Whereas both these species could be exploited for direct human consumption or for other uses. Lake files, which used to be eaten, are no longer being utilized because now there is plenty of fish, but these also could be caught and used in the manufacture of animal feeds.

Rare Species in the Catches

In the past there used to be species which were of great commercial importance but which are now rare in the catches. These include Labeo victorianus, Alestes jacksonii, Alestes sadleri, Schilbe mystus and to some extent Mormyrus sp. Specimens of these species are recorded from time to time indicating that the species still exist but they have somehow been affected by human activity on the lake.

It is necessary to have a project worked out and directed toward the ncrease in recruitment of these species. This is urgently required because it will be very unfortunate if we lose these species completely.

Updating of Information on Physical Characteristics of Lake Victoria

At the beginning of the present century, good work was done to produce the Navigation Chart of Lake Victoria. This same chart is still in use, but experience has shown that there are a number of physical features in parts of the lake which are not marked on the chart. If modern methods of fishing are going to be used, we need to update the present Navigation Chart.

The navigation lighting along the shore of the lake needs to be reactivated. This is something which has been discussed sometime but action has not been taken.

CONCLUSION

The stocks of Nile perch in Lake Victoria should be exploited to the maximum. However, the fact that this species dominates the catches should not be taken as a reflection of what is in the lake. This information can only be gained by a full stock assessment of Lake Victoria upon which management strategies for the lake can be based.

It is necessary to devise means of optimizing the utilization of the fauna of the lake. Species like bivalves should be exploited for direct human consumption while the lake flies should be trapped and used in the manufacture of animal feeds.

The enhancement of recruitment of rare commercial species like Labeo victorianus, Alestes jacksonii, Alestes sadleri, Schilbe mystus and to some extent Mormyrus sp. should be given serious attention so that these species are not completely wiped out. A project should be mounted for these species.

For the sake of safe navigation on the lake, the present Navigation Chart needs updating, while the shore navigation lighting should be reactivated.

APPENDIX D.2
THE STATE OF LAKE VICTORIA FISHERIES, KENYA WATERS

by

J.Ogari and A.Asila
Kenya Marine and Fisheries Research Institute
P.O. Box 1881
Kisumu, Kenya

INTRODUCTION

Aquatic research on Lake Victoria has been in operation since 1909, though without a pattern of continuity until the inception of the East African Freshwater Fisheries Research Organization (EAFFRO) from which three national research institutes took over. Kenya Marine and Fisheries Research Institute (KMFRI) was set up by an act of Parliament in Kenya and charged with the following objectives amongst others in Lake Victoria:

1. to carry out research on fish population dynamics and general water ecology;

2. to collect and disseminate scientific information on fisheries resources which will form a basis for utilization, and

3. to study and develop important species for fish culture in fresh waters and their rearing procedures.

When the East African Community was dissolved, KMFRI took over in Lake Victoria inheriting unique problems. Haplochromis stocks which were observed in Kudhongania and Cordone (1974) were dwindling and Lates niloticus fishery was expanding. There was an outcry at the disappearance of Oreochromis esculentus and anadromous species. The sprouting of industries and increase in farming activities were a potential problem in areas identified. All these led to special attention on studies of the ecology of Lates niloticus, limnology and water quality and pollution.

Review of Research Activities

Okemwa (1985) summarized the basic problems under study in KMFRI, other areas which were not included in the summary were fish culture and fishery economics and marketing.

In stock assessment basic parameters have been estimated (Asila and Ogari, 1988, Asila, Ogari, Rabuor, 1989; Getabu, 1988; Ochumba and Manyala, 1989; Okemwa, 1984, 1985). Growth rates, mortality rates and stock densities of Lates niloticus, Oreochromis niloticus and six riverine species were discussed. Estimates of biomass and fishing patterns of various species within the Kenya waters have been reported. Various factors have been discussed with respect to the management of the fisheries in the lake. Continuous monitoring of stock levels through trawl surveys is the ongoing project in this field.

Catch-effort assessment has been monitored by KMFRI since 1978, presently covering 24 beaches and has been the subject of summaries of catches and other scientific papers (Rabuor, 1988, 1989; Asila, 1988).

In order to tackle the problems of the expansion of the Nile perch fishery and the decline in other fish stocks, studies were initiated on the feeding and reproductive ecology of Lates niloticus, Bagrus docmac and Synodontis sp. in the Nyanza Gulf of Lake Victoria (Ogari, 1984; Ochieng, 1982; Mainga, 1981; Getabu, 1989). Current work on fish ecology is on Rastrineobola argentea and other biological aspects on the species that have already been studied, including close monitoring of the Nile perch fishery.

Limnological studies have been conducted in KMFRI and emphasis has been on phytoplankton and zooplankton distribution. Kibaara (1989) reported that the most dominant organism in the phytoplankton of the Nyanza Gulf was the blue-green algae Microcystis aeroginosa with a biomass of 150 mg 1^-1, followed by Anabaena sp. It has also been reported that chlorophylla concentrations showed two peaks May to June and October to January with lower concentration at the surface than at the bottom. The highest photosynthetic rate of 1.2 g 0 m^-3 h^-1 was recorded in Nyakach Bay in January 1987 compared to 0.65 g m h ^-1 reported by Talling (1965). Measurements of other limnological factors also undertaken particularly in response to the massive fish kills observed in 1984 (Ochumba and Kibaara, 1988). Benthic ecology has not been tackled at all.

Environmental studies have concentrated more on water quality analysis. Onyari (1985) worked on the heavy metals analysis in sediments and fish muscles from the Nyanza Gulf of Lake Victoria. Ochieng (1987) worked on the trace elements analysis in inland waters and concluded that inland waters meet WHO (1971) drinking water standards and standards related to aquatic environments and that the bicavailable (total exchangeable) metal concentrations compared very well with the concentrations in the fish muscles.

On fish quality, a project has already been concluded on improved utilization of Nile perch. Several products and by-products were developed in the project. Currently, work is proceeding on reduction in post harvest losses; in fish culture, where trials in cage culture are being made as a solution to early predation and fingerling production, and is not available yet; fisheries economics and marketing.

Composition and Distribution of Fish Species in Nyanza Gulf

The present trend in Kenya waters indicates that although the three taxa, O. niloticus, R. argentea and L. niloticus still dominate the fishing industry, other species which had disappeared between 1981 and 1986 are showing an increase in catches in some landing beaches. Their reappearance in Nyanza Gulf has been confirmed by bottom trawl surveys carried out in 1988/89. Results from trawl catches indicate notable recoveries of fish species including Bagrus docmac, Protopterus aethiopicus, Schilbe mystus, Mormyrus karumme and some Haplochromines within water depths of 3–6 m. Oreochromis niloticus which during 1981–86 survey was rarely observed in trawl surveys in the shallow open waters, has been observed more often in trawl hauls in corresponding depth range. Lates within 3–6 m depths which during the 1981–86 survey had declined is now showing higher catches (Table 1). The present trend is supported by landing data at beaches like Kusa, Dunga, Kaloka, etc., which cater for fish caught from depths less than 10 m.

The probable reasons for the increase in other species in the shallow open waters may be due to both change by fishermen toward use of large mesh gillnets to catch Lates, thus allowing other species to flourish, and also the decline of Lates as a predator within the corresponding depths. On the other hand, the present increase in Lates catches within water depths less than 10 m, may be attributed to the decline of prey species in water depths above 10 m and vice versa. The ecological consequences of the changes induced by Lates cannot be predicted yet as the ecosystem is still changing.

During the present survey the largest Lates caught was 120 cm total length and it was also observed from the trawl catches that larger Lates above 90 cm were rare. It is however probable that larger Nile perch could still be available within water depths of 0–3 m or 6 m and above. It is still too early to predict whether the Lates population is on the decline. Trawl hauls during the present survey indicated the presence of O. niloticus measuring about 60 cm and weighing about 5 kg. Results from some selected landing beaches along Kenya waters of Lake Victoria indicate some decline in Lates landing between January and July 1988/89. The observed decline may be due to the migration of Lates from deeper waters to shallow waters, and also a tendency by fishermen to reduce mesh-sizes to catch other species as they reappear.

This renewed use of small meshed nets may result in a further decline in catches of all those fish species which are now showing some signs of recovery. If these species are subjected to substantial fishing pressure as they endeavour to recover and at the same time Lates shifts from its present prey of Caridina nilotica to these species, then the ultimate result will most likely indicate a decline in catches of all fish species within Kenya waters of Lake Victoria.

Priorities in Future Research Activities

Understanding of the fish communities and their prey and the ecology of the benthic community should form the top priority on the research work of Lake Victoria to gain Caridina nilotica which forms an integral part of Lates prey which has not been given due attention. studies on effluent discharges into the rivers within the lake basin also form one of the top priorities.

Table 1

Catch compositon by weight in kg/hour of species caught at stations sampled

Note: - no catch

+ less than 1.0 kg/hour

Table 2

Catch data for 1988

REFERENCES

Asila, A. 1988. Stock size and fishing patterns of Lates niloticus (Manuscript presented to HYSEA in December 1988)

Asila, A. and J. Ogari, 1988. Growth parameters and mortality rates of Nile perch (Lates niloticus) estimated from length frequency data in the Nyanza Gulf (Lake Victoria).

Asila, A., J. Ogari and C. Rabuor, 1989. Relative changes in mean size and biomass of Nile perch (Lates niloticus) in the Kenya waters of Lake Victoria. (Manuscript presented to FAO/DANIDA Mwanza)

Getabu, A., 1988. Some aspects on the biology of the Lake Victoria fisheries with particular emphasis on Oreochromis niloticus and Alestes sadleri from the Nyanza Gulf.

Getabu, A., 1989. The culture and food of Oreochromis niloticus in waste water lagoons. M.Sc. Thesis, University of Nairobi

Kibaara, D., 1989. Primary productivity dynamics in the Winam Gulf of Lake Victoria. M.Sc. Thesis University of Nairobi, 189 p.

Kudhongania, A.W. and A.J. Cordone, 1974. Bathospatial distribution patterns and biomass estimates of the major demersal fishes in Lake Victoria. Afr.J.Trop.Hydrobiol.Fish., 3:167–181

Mainga, O.M., 1981. Some hydrobiological observations at the mouths of two affluent rivers of Lake Victoria with special emphasis on Synodontis (Pisces:Mochokidae). M.Sc. Thesis, University of Nairobi

Mainga, O.M., 1985. Preliminary results of evaluation of fishing trends in the Kenya waters of Lake Victoria from 1981 to 1982. FAO Fish.Rep., (335):110–16

Ochieng, E.O. 1987. Limnological aspects and trace element analysis of some selected Kenyan natural inland water. M.Sc. Thesis, University of Nairobi

Ochieng, J.I.O., 1981. Reproductive biology and feeding ecology of a predatory siluroid catfish, Bagrus docmac forskahl (Pisces: Bagridae) in Winam Gulf of Lake Victoria, East Africa. M.Sc. Thesis, University of Nairobi

Ochumba, P.B.O. and D.I. Kibaara, 1988. An instance of thermal instability in Lake Simbi, Kenya. Hydrobiologia, 158:247–52

Ochumba, P.B.O. and J. Manyala, 1989. Growth and related statistics of six riverine species in the lower Sondu-Miriu river (manuscript presented to FAO/DANIDA seminar in Mwanza)

Ogari, J., 1984. The biology of Lates niloticus in the Nyanza Gulf of Lake Victoria (Kenya) with special reference to the food and feeding habits. M.Sc. Thesis, University of Nairobi.

Ogari, J. and S. Dadzie, 1988. The food of Nile perch, Lates niloticus (L.) after the disappearance of the Haplochromine cichlids in the Nyanza Gulf of Lake Victoria. J.Fish.Biol., 32:571–7

Okach, J.I.O. and S. Dadzie, 1988. The food, feeding habits and distribution of a siluroid catfish, Bagrus docmac (Forskahl) in the Kenya waters of Lake Victoria. J.Fish.Biol., 32:85–94

Okemwa, E.N., 1984. Potential fishery of Nile perch (Lates niloticus) Linne (Pisces: Centropomidae) in Nyanza Gulf of Lake Victoria. East Africa. Hydrobiologia, 108(2):121–6

Okemwa, E.N., 1985. Principal gaps in the knowledge of fisheries of Lake Victoria (Kenya waters). FAO Fish.Rep., (335):117–22

Onyari, J.M., 1985. The concentration of manganese, iron copper, zinc, cadmium and lead in sediments and fish from Winam Gulf of Lake Victoria and fish brought in Mombasa town markets. M.Sc. Thesis, University of Nairobi, 282 p.

Rabuor, C.O., 1988. Catch and effort assessment survey for the artisanal fisheries of Lake Victoria (Kenya waters, 1987). KMFRI Tech.Pap., (2)

Rabuor, C.O., 1989. A preliminary report on catch and effort assessment survey of the artisanal fisheries of Lake Victoria, 1988. KMFRI Tech.Pap., (3)

APPENDIX D.3
THE STATE OF LAKE VICTORIA FISHERIES, TANZANIAN SECTOR

by

P.O.J. Bwathondi
Tanzania Fisheries Research Institute
P.O. Box 9750
Dar es Salaam

INTRODUCTION

As early as 1927 it was suggested that large piscivorous fish should be introduced in the lake to feed on the usually small bony fishes, the Haplochromis with the hope that the piscivores will grow to large sport fish. Attempts were made to introduce several exotic species in the lake in the search for bigger fish in the lake. Among the introduced species that are doing particularly well are Lates niloticus and Oreochromis niloticus. It is believed that there are three species of Lates in the lake, namely, L. niloticus, L. macrophthalmus and L. longispinus (Bwathondi, 1987).

Since the introduction of Lates spp. in Lake Victoria in the late 1950s and early 1960s great ecological changes and species variations have taken place. The Nile perch and Nile tilapia have also deeply influenced the nature of the fishery of the lake.

In 1973 FAO/UNDP assessed the stocks of the lake finding that up to 80% of the demersal ichthyomass of the lake consisted of more than 150 species of Haplochromis. Based on this knowledge, one fishmeal company, the Nyanza fishing and Processing Company (NFPC) was established to manufacture fishmeal using Haplochromis caught by trawlers. The activities of NFPC did not last long, as the target species became prey to the introduced species reducing their numbers so greatly that it was uneconomical to use them as a source of fish for the factory. Faced with the danger of closing down due to lack of fish, NFPC tried to explore the use of Nile perch in their fish meal, but due to the fatty nature of the fish, it was not possible to use it in the factory. This fact led to the end of fishmeal production in Mwanza by NFPC.

The Lake Victoria fishery of about 217 162.4 t (in 1986) in the Tanzanian sector constituted 56.2% of the total fish catch of Tanzania from all sources during the same period. However, this high production did not persist as will be considered later. Catch from the lake showed a big drop in 1987 (159 915.21 t or 46.7% of the total fish catches in Tanzania for the same period, equivalent to a drop of 9.5%). The fishery of Lake Victoria now supports about 22 207 registered and more than 30 000 unregistered occasional artisanal fishermen. The lake provides a monthly average income of T.Shs. 1 170.00.

Recent Trends of Lake Victoria Fishery

Table 1 summarizes the trend of Lake Victoria fishery between 1981 and 1987. Table 2 summarizes the species composition of the Tanzanian sector of Lake Victoria fisheries.

Prior to the 1950s, the Lake Victoria fishery consisted of several species of both indigenous and introduced species. Most of the species in the lake were relatively small and occurred in shallow littoral areas. Among the large species at this time were Protopterus, Bagrus and Clarias. There were also more than 150 species of Haplochromis, Alestes and Rastrineobola argentea. The tilapiine group was next to the haplochromines in abundance. After the introduction of the Nile perch, both species distribution and abundance changed greatly.

The number of fishermen fluctuated from the lowest figure of 15 194 in 1983 to 24 241 in 1986 with an annual average of 19 296 between 1981 and 1987 (Table 1). The peak in 1986 was followed by a drop of 8.4% the following year. During the same period the number of fishing craft also fluctuated with the highest figure in 1986 and lowest in 1983. Table 3 compares the average number of fishermen per fishing craft, average catch per boat and average catch per fisherman. It is seen that there were more fishermen per boat/canoe between 1981 and 1985 than between 1986 and 1987. One would however expect the size of the boats to be smaller because of the smaller number of fishermen per boat during the same period. But on the contrary most new boats being built are slightly larger than the old ones. Besides these new boats are more efficient than the old ones. There were more fish caught per boat between 1986 and 1987 than between 1981 and 1985. The average catch per fisherman also increased from 3.5 t in 1981 to 9 t in 1986 and a slight decrease to 7.2 t in 1987.

Table 4 summarizes catch statistics of the Nile perch in the three regions of the Tanzanian sector of Lake Victoria.

Nile perch

There has been a dramatic change in species composition in the fishes of the lake over the past decade (Table 2 also see Bwathondi, 1987). The catches of Lates sp. increased from 273.8 t (0.4%) in 1981 to 123 894.9 t (57.25%) in 1986. Although the absolute figures for Nile perch catch for 1987 show a slight decrease, the percentage contribution to the catch increased (60.96%). The overall fall in fish production between 1986 and 1987 is partly attributed to the fall in catches of Nile perch and partly to the fall in catches of other fish species, e.g., Haplochromis (a fall from 7.84% to 0.9%), Bagrus (a fall from 8.07% to 4.8%).

Table 4 compares catch statistics of Nile perch in the three regions of the Tanzanian sector of Lake Victoria. It is now known that Lates colonized the lake on a clockwise direction starting with the Mara region in the north through Mwanza in the south to Bukoba in the west. Catches for Lates in Mara region increased from 2% in 1981 to 77.2% in 1987. Similarly the percentage composition of Lates in catches from the Mwanza region steadily increased from 1.0% in 1981 to 63.55% in 1987. Nile perch catches for 1986 reached 25 864.63 t (26.46%). Catches of Lates for the Kagera region fluctuate without a given trend. For example, in 1984 the catches were highest on a percentge basis (51.5%). Catches for 1986 though seemingly low in percentage basis (41.6%) are actually higher by weight (see Table 4). There was an abrupt fall in the catches for the year 1985 (a fall of 60.92%). In the following year there was a sharp rise in total weight of Lates (rise of 171% in weight) before a fall in 1987 of 39.6% in weight.

When considering the fall in catches for 1987, an attempt was made to look at the fishing gears for all fishes. Table 1 summarizes the fishery statistics for the Tanzanian part of Lake Victoria. In this Table it is obvious that there has been a rise in use of certain fishing gear and fall in others. The most abundant fish in the lake is the Nile perch. The most effective gear for catching Nile perch, besides beach seines and trawlers are the 6–8 inch mesh size gillnets.

Figures 1 and 2 compare the production of Nile perch with the different mesh sizes. From work carried out in the lake, nets popularly used to catch Nile perch are 7 and 8 inch mesh size. The two types of nets when compared showed that there was a sharp increase in 8 inch mesh size nets in 1986 then a fall in 1987 whereas those of 7 inch mesh size steadily increased. When a comparison was made between gillnets of 5–7 inch mesh size and those of 8–12 inch mesh size, a similar trend was seen (Figure 2). A comparison between Figures 1 and 2 confirm that gillnets of mesh size 8 inch were the most effective in capturing the Nile perch, hence their increase will increase the catches of Nile perch. From reports on the sale of gillnets in the lake, particularly in Mara region through commodity assistance by NORAD, it is seen that many pieces of gillnets of mesh size 7 inch were sold to fishermen in Mara Region. This sale has greatly increased the catches for the year 1988 (report not ready yet).

Other Fishes

In Table 2 it is seen that the catches of most other fishes have declined. Catches of Haplochromis, for example, have declined from 24 593 t or 34.8% in 1981 to 1 488 t or 0.9% in 1987. It is believed that the decline in haplochromine species is attributed to heavy predation by the Nile perch. Furthermore, it was believed that the Nile perch will completely consume the haplochromines from the lake. Reports from fishermen and work done by TAFIRI through IDRC sponsorship now indicate that the catches of haplochromines are increasing in some areas.

Other species whose catches have declined include (with 1987 percentage total in brackets): Labeo (0.14%), Bagrus (4.8%), Barbus (0.44%), Protopterus (2.4%), and Synodontis (2.9%). It is reported that although Alestes had almost completely disappeared from catches in the past, small populations of them are now spotted in pockets along the lake. It is quite likely that reports for 1988 and 1989 should record their presence in the catches.

Rastrineobola argentea (dagaa) is now considered the most important pelagic species of fish in the lake (4 063.47 t of dried dagaa or equivalent to about 12 190.4 t fresh/wet dagaa by 1987 (see Fisheries Statistics, Tanzania Mainland, 1987)). HEST reports indicate a dramatic increase in Rastrineobola in the Mwanza area (in fact the figure given for the dagaa for 1987 (4 063.47 t) comes from Mwanza alone). Both Mara and Kagera regions have not recorded the dagaa catches although physical inspection at the landing beaches have confirmed the growing fishery of dagaa in the two regions. Bwathondi (1987) mentioned that the increase in the dagaa catches were due to actual increase in numbers of fish in the lake. Ssentongo (1985) reports that the dagaa produces numerous pelagic eggs. Because of the decrease in number of its competitors, especially the haplochromines, Rastrineobola is now doing well in the lake. Work carried out in Shirati (IDRC project) has observed that both juvenile Nile perch and the dagaa are the main fish prey for larger Nile perch. Small Nile perch feed on Caradina sp. Mwambungu and Msuku (1989) have reported a good fishery of dagaa in Tarime district using imported mosquito nets (the fishery is called “hurry up” as it catches all fishes encircled by the net due to their very small mesh size).

Although in Table 2 it is seen that the catches of tilapias are decreasing, the decrease is not uniform for all species. Endemic species like Oreochromis esculenta are on the decrease, whereas the introduced Oreochromis niloticus is on the increase. Reports from the lake indicate that in 1986, 10 584.36 t (4.89%) of O. niloticus were harvested and in 1987, about 6.2% (9 939.04 t) of the catches were O. niloticus. The Nile tilapia has been reported to co-exist with the Nile perch. For example, Ogutu-Ohwayo (1984) reported such a phenomenon in Lake Kyoga. It is now believed that the great resistance of O. niloticus to Nile perch predation is attributed to the possibility of hybridization of O. niloticus with O. esculenta or others. More work should be done to prove this theory. The fishery of O. niloticus in showing a bright future. In Shirati area, the fish is caught in baits of green filamentous algae or sometimes encircled by gillnets and the fish chased by divers into the nets (this practice is known as “Katuli”).

Post Harvest Losses

While working on the post harvest losses of fishes in Lakes Victoria and Nyasa, Bwathondi (1989) observed that during rainy seasons and glut catches, fish spoilage in Lake Victoria can reach 50%. He recorded that losses in economic value are generally attributed to fishermen sometimes landing their catches late (sometimes incurring losses of up to 50%), fish processors processing semi-decomposed fish and finally for fish traders keeping processed fish for longer periods resulting in reduced shelf life due to fungal and bacterial attack. Physical losses were reported by Bwathondi (1989) to be caused mainly by insect infestation particularly beetles and blowflies and fragmentation.

Future Research

Currently Lake Victoria fisheries are attracting many researchers from within the region and outside. It is recommended that external donors should assist the scientists in the region to strengthen their research capabilities. There are good young scientists in the region who should be encouraged to work on the Lake Victoria fishery. The following are some of the research areas:

1. Stock assessment of Lake Victoria fishery. As mentioned in my introduction the stocks of the lake were assessed by FAO/UNDP in 1973. During this period the Nile perch had not established itself. It is now considered important to assess the fish stocks of the lake;

2. The study of Nile perch should be encouraged. Assistance of IDRC to TAFIRI and UFFRO should be encouraged and extended to KMFRI. Work done by HEST in Mwanza should be acknowledged;

3. Since Rastrineobola argentea has shown to be a promising pelagic species in the lake, immediate work should begin on its biology and fishery. This should include the assessment of their stocks;

4. Nile tilapia, Oreochromis niloticus also has a promising future in the lake. Its biology and fishery should be studied. Further work should be extended to the development of efficient and effective gear to capture the fish;

5. Post harvest losses - from work carried out through assistance by the African Bioscience Network (ABN) it is seen that on average 25% of our fish catches are lost. This is equivalent to 39 978.8 t for 1987 catches. Bwathondi (1989) made several recommendations directed at decreasing losses. Among the recommendations are use of efficient, less fuel consuming kilns (participants should be able to visit and view the new kiln at TAFIRI centre during the meeting). Work on post-harvest losses of the fishes of the lake should be encouraged;

6. Management of the lake fishery. It is true that fishes in the lake do not have any boundaries as such the riparian states have to collaborate on the optimization of effort to usefully exploit the resources. For conservation purposes there should be joint efforts by all the states to form one or uniform conservation measures on the lake fishery. For example, the use of mosquito nets (“hurry up”) which are banned in one state should not be allowed in another state; the observation of closed seasons areas should be respected by fishermen from all countries.

REFERENCES

Bwathondi, P.O.J., 1987. The state of Lake Victoria Fisheries, Tanzania Sector. Paper presented at the Fourth Session of the CIFA Sub-Committee for Lake Victoria, 6–10 April 1987, Kisumu, Kenya. FAO Fish.Rep., (388):29–35

Bwathondi, P.O.J., 1989. Post-harvest losses in the fisheries of Lakes Victoria and Nyasa (Malawi). Paper presented to ABN sponsored workshop on post-harvest losses in fishes, 1–4 August 1989, University of Dar es Salaam, Tanzania

Fisheries Division Annual Statistics, 1987. Ministry of Lands Natural Resources and Tourism, Dar es Salaam

Mwambungu, J.A. and B.S. Msuku, 1989. The artisanal fishery in Eastern Lake Victoria (Tanzania). Report of a frame survey conducted from Kirongwe Village (Kenya-Tanzanian border) to Mara River

Ogutu-Ohwayo, R., 1984. The effects of predation by Nile perch, Lates niloticus (Linne), introduced into Lake Kyoga (Uganda) in relation to the fisheries of Lake Kyoga and Lake Victoria. FAO Fish.Rep., (335):18–41

Ssentongo, G.W., 1985. Recent trends in the fisheries of the Tanzanian Sector of Lake Victoria. FAO, Rome, 13 p.

Table 1

Summary of fishery statistics from Tanzania territorial water of Lake Victoria for 1981–87

Table 2

Species composition of fish carches in Lake Victoria (Tanzania) with percentages in parentheses (in tons)

Table 3

Comparison among average number of fishermen per boat, average annual catch per boat and average annual catch per fisherman

Table 4

Catch statistics of Nile perch in the three regions of the Tanzania sector of Lake Victoria

Figure 1 Comparison between 7 and 8 inch mesh size nets used in Lake Victoria to capture Nile perch between 1981 and 1987

Figure 2 Comparison between 5–7 inch and 8–12 inch mesh size nets used in Lake Victoria to capture Nile perch between 1981 and 1987