Observer opinion on Nile perch is roughly divided into two camps (see Appendix B). On the one side are those who regard the introduction of Lates as a great calamity for Lake Victoria; on the other are those who regard the fish as a positive development, or at least not as a wholesale disaster. These positions can now be considered further in light of the foregoing review of the fisheries situation within each of the three country portions of the Lake.
5.1.1. Ecological Disruption
Those who see the Nile perch as a “calamity” for Lake Victoria stress that the introduced predator has thrown ecological balances into severe disarray and drastically depleted endemic fish stocks, which represent crucial subsistence and commercial resources for human communities and invaluable objects of biological study.
The technical ecological and biological issues involved with this line of argument do not lie within the scope of the present review, and were not addressed in detail. But there are various aspects to the argument and they need to be recognised and judged on their respective merits. First of all, it must be acknowledged that very serious questions are at stake. There can be no doubt that the establishment of such a highly successful predator as Lates in Victoria waters carries profound implications for the pre-existing or traditional trophic structures of the lacustrine environment. The long-term consequences of changes in niche utilisation patterns remain unclear, however, and have thus become subjects of considerable speculation. Most alarming are the forecasts which start by taking the apparent demise of various planktivores, algal feeders, and other specialised fish species as presumptive evidence of critical breakdowns in the energy processing chains of the Lake. The supposed cumulative development of inefficiencies and general trophic instability is then projected to lead ultimately to lacustrine system collapse. On the other hand, it can be noted that Lake Victoria is in the midst of a fundamental transition, as one sort of ecological energy processing system is evolving into another. It may be that the gaps, slacks, or vacancies that have been created in the food web structure of the lake will be taken up by other organisms in other ways, so that energy flows will continue to cycle effectively within the system.
Other aspects of the “ecological disruption” line of argument need to be looked at critically as well. While there are strong indications that the presence of Nile perch has had a disruptive effect on pre-existing fish stocks in the Lake, particularly amongst the haplochromines, the valuations of these stocks (a) as case material for the study of lacustrine ecology and evolutionary biology, and (b) from a human welfare point of view, are not necessarily one and the same.
In the former connection (a), the disappearance of certain cichlid species may indeed constitute an enormous loss, and a strong argument may well be made for such salvage conservation measures as can now be mounted (Balon and Bruton 1986; Coulter et al. 1986; Ribbink 1987). Yet it should be recognised too that other factors have certainly contributed to the decline of various fish stocks over the years. To some extent these include environmental perturbations (e.g. floods, storms, algal blooms, and perhaps pollution) which bring sudden shifts in water levels and quality. But most of all it is the effect of simple overfishing of favourite target species that is crucial here. Repeated observations were made about overfishing of tilapia stocks, for instance, beginning well before Lates colonisation became a concern (Graham 1929; Beauchamp 1955; Mann 1970; Wanjala and Marten 1974; cf. Ogutu-Ohwayo 1988). It is noteworthy that many of the local fishermen interviewed during the mission frankly acknowledged overfishing as a serious problem. Additional human interventions such as the construction of the Mbita Causeway at the entrance to Nyanza Gulf are perceived to be disruptive of fish stocks as well. In other words, lakeshore residents themselves do not regard the Nile perch as the sole perpetrator of endemic stock declines.
In terms of the human welfare connection (b), specialised scientific and academic concerns must be mediated by those of a more immediate and utilitarian nature. The significance of fish stocks needs to be judged also, and indeed primarily, from the perspective of community livelihood.
5.1.2. Loss of subsistence and Commercial Resources
The role of Haplochromis stocks as important food and cash resources for lakeshore communities in the past has not been well documented. Haplochromines seem to have represented a food of last resort around much of the Lake, as reflected in fisheries reports about their relatively low level of exploitation (e.g. EAFFRO 1960) and poor marketability (Dhatemwa 1982; Nyholm and Whiting 1975). In recent years price levels for Nile perch, which have made up a far greater proportion of the total catches in the Lake, have been either on a par or substantially higher those for haplochromines. (see Tables 2.4., 3.6., 3.7). Although the attempt to develop a trawl fishery for Haplochromis in the Tanzania sector beginning in the mid-1970s is often said to have collapsed because of the eradictation of stocks by Lates, it is very doubtful that haplochromines could have withstood the pressure of large-scale commercial exploitation (Goudswaard and Witte 1985; cf. Wanjala and Marten 1974).
In any event, it is clear that the abundance of haplochromines has been greatly reduced nowadays, probably owing mostly to Nile perch predation but to some extent (in Tanzania) perhaps to the impact of industrial trawling as well. Yet it is by no means clear that this should be regarded to be the “disaster” for local fisherfolk that some critics have alleged. Indeed, if lakeshore dwellers' own stated reactions and the documentary evidence assembled by the mission offer any guides, there are no reasons at all to speak of a “disaster” from a food resource/commercial value point of view.
Reference should also be made to other important species groups which were significantly contributing to the landings in the 1970s, and commanding relatively high prices. These include Clarias, Protopterus, Bagrus, Synodontis, and Schilbe especially. According to available statistics, catches for these fish have decreased markedly in Kenya since 1980 (Table 2.3), whereas in Tanzania catches have remained fairly high (Table 3.3). These trends are corroborated by the mission field observations. For Uganda, it was learned that catches of these fish have generally been on the decline, although Clarias and Protopterus appear to have been less affected. Different catch levels possibly reflect both a difference in stock abundance and fishing practices (varieties of specialised gear used) between the three country sectors.
The extent to which Lates predation has contributed to the decline of these other species groups is difficult to assess. Some fish like Protopterus and Clarias may be relatively immune to predation by Nile perch because of their habitat ranges. On the other hand, they may be subject to indirect pressure from Lates due to competition for common prey stocks.
Whatever the factors underlying the decrease of Haplochromis and the other, more preferred endemic species stocks -- predation, overexploitation, or some combination of causes -- the total supply of fish from Lake Victoria has in the meantime more than compensated for these losses. The trends have shown strong similarity to the situation that developed in Lake Kyoga, where new species introductions carried out in the mid-1950s and subsequent adjustments in stock balances led to fisheries based principally on Lates, O. niloticus, and R. argentea. Parallels with Lake Kyoga are addressed more fully in the concluding section (5.1.6.) of this review.
It is commonly acknowledged that fisheries statistical records in all three riparian states are woefully inadequate. Despite manifold shortcomings, however, they do provide rough measures of catch magnitudes and trends over the recent past. They may be used generally to demonstrate the decline in Haplochromis and certain other indigenous fish stocks, for instance. They may also be used to demonstrate the dramatic upsurge in Lates catches. Together with other lines of evidence, such as those from research reports and field interviews, the records suggest that overall fish yields have strongly increased since the Nile perch introduction.
Summary indications cited earlier in the report are drawn together in Table 5.1. Over the period 1975–1985, estimated total catches increased from 676 to 137,637 t for Nile perch, from 11,684 to 30,093 for tilapia, and from 6573 to 33,966 for R. argentea. Catches of haplochromines decreased by some 50% during this interval, while the catches of other species remained generally stable, despite country-to-country variations. Table 5.1 indicates that overall estimated production from the Lake rose from about 88,000 t in 1975 (a level that is fairly average for the 1970s) to over 250,000 t in 1985.
With due regard for the imprecision of available information, it is still quite certain that fishermen are catching greater tonnages nowadays despite changes in the species composition of the harvests. They have, in short, adapted to the new realities of the Lake fisheries and turned them to advantage. While Nile perch tonnages have reached spectacular proportions, the small pelagic dagaa (R. argentea) and the introduced tilapia O. niloticus are also important components of the new realities of Lake Victoria fishing. Both of these fish have registered impressive gains in catch return records over the last ten to fifteen years. Along with Lates, they make up a new commercial and subsistence resource base in the Lake.
The catch trends depicted in Table 5.1 can be translated into monetary value using a price index which yields estimates in terms of constant 1987 US dollars. Gaps in the price records and questions about currency exchange standards over the last decade or so make it difficult to comment with any precision (see notes for Table 5.1), but very roughly it can be estimated that the value of landings has risen from a level of US$ 25 million in 1975 to US$ 72 million in 1985.
The results in Table 5.1 suggest that the total catch from the Lake over the 10 year period 1975–1985 just about tripled in quantity and value.
As far as the evolution of the fisheries since 1985 is concerned, more recent (but still preliminary) landing statistics show further increases in total catch in both Kenya and Tanzania. Catches are also reported to be increasing in Uganda. A level of 300,000 t per year is probably now attained in the total statistical reckonings for the three states.
Not even the most optimistic of observers would expect continued unremitting growth in the Victoria fisheries. Obviously there are limits, and species stocks will eventually adjust to certain population ranges, depending on dynamics of predator-prey interaction, further expansion of the fishing effort, and so on. Perhaps the process of adjustment will culminate at a level of production around the current high reckonings noted above; perhaps (and more likely) it will settle at a rather lower level. In any case, the ultimate gross value of the Lates presence to the riparian populations would remain very substantial. Table 5.2 shows the results of an attempt to quantify total benefits across a 15 year period (1980 – 1994) according to a range of scenarios, based on hypothetical levels at which the fisheries stabilise. Total benefits are gauged against the average pre-Nile perch production level. Assuming a production peak of 250,000 t in 1987 and a subsequent sharp decline to the 100,000 ton level, total benefits would lie in the neighbourhood of US$ 800 million. Assuming a peak of 300,000 t in 1987 and a subsequent stabilisation level of 250,000 t, total benefits would amount to about US$ 1500 million. While these figures are based on hypothetical production levels, they are indicative of the magnitudes of wealth generation that the transformations wrought on the Lake fisheries by Nile perch may entail. They suggest at the very least that even if overall production drops dramatically and eventually stabilises around the pre-Nile perch levels observed in the 1970s, the ultimate economic gain for local fisherfolk will have been prodigious.
The mission noted a significant decrease in catches of Nile perch and other species within Kenya's Nyanza Gulf, a rather definite sign of overexploitation which should be viewed very seriously. The decline has led fishermen increasingly to operate along the outer shore. In contrast, Ugandan and Tanzanian fishermen reported that catch rates for Nile perch have remained strong over the last three years. It was further observed that the R. argentea fishery in Kenya and Tanzania has continued to expand, with the growth in Tanzania being particularly remarkable.
The question of overriding concern is of course whether present catch levels are sustainable or not. Despite definite and gloomy pronouncements on the future which have come from some conservationist-minded authorities, it may be supposed that the long term resolution of species stock balances and the state of fishing in the Lake will turn on a complex of factors -- some currently known or suspected, and others imponderable. The eventual outcome eludes easy prediction.
Further consideration will be given to the question of sustainability later on (Section 5.1.6). For the present, it is important to bear in mind that while the composition of catches may have narrowed considerably, the Lake fisheries are still multispecific, even though currently dominated by Nile perch. As the country reviews showed, a fairly wide variety of other indigenous fish are yet to be found, and specialised fisheries still exist in a number of areas (e.g. the Bagrus and Synodontis fisheries in the Mwanza and Mara regions of Tanzania). Furthermore, the action of fishermen themselves constitutes an important variable to take into account. Field observations confirmed earlier reports that fishing gear has been adapted so that Nile perch may be captured more effectively, and that most fishermen are now targetting this species. The probable effect of these developments is to multiply pressure on Lates and to reduce it for the immature and smaller sized fish of other species which are able to escape the larger gillnet mesh sizes being used.
5.1.3 Resentment towards Nile perch by Local People
Critics have pointed out that people around the lakeshore resent Nile perch for destroying traditional and preferred food fish, ruining fishing gear, being an unpleasant food in itself, and having a poor market.
The country reviews show that the above statement fairly characterises local reaction to Lates in the initial stages of its proliferation around the lakeshore, except in Uganda, where it was already a familiar product of the Lake Kyoga and Lake Albert fisheries. Direct testimony from fishermen and traders in Kenya and Tanzania indicated that the fish did arouse strong negative feelings when it first appeared on the scene, and for the very reasons cited. Yet the same line of testimony indicated that within a rather short range of time people's views began to change dramatically, to a point where the new fish became widely regarded as not only an acceptable, but a positively welcome development.
The small meshed nets which were previously in common use and which were easily damaged by Nile perch gave way to heavier, more appropriate gear as fishermen adapted to the changing technical requirements. Consumption habits in lakeshore and inland communities began to adjust to new circumstances of fish supply, and markets for the fish developed in places where they did not exist before. It is clear that there are still many who do not appreciate Nile perch as a food, and more needs to be learned about patterns of consumer preference and what underlies them. It is also clear that old favourites like tilapia are still the fish of choice for many consumers, especially in the narrow belt around the shore.
Be that as it may, Nile perch has achieved considerable popularity amongst consumers as a palatable, relatively cheap, and readily available fish, and amongst fishermen and traders as a valuable commercial asset. This has been the case for some time, despite the rather sensational reports to the contrary which have continued to appear in the press and elsewhere. In this regard, local reaction to the loss of Haplochromis stocks also seems to have been the subject of some exaggeration. Judging from what could be learned during the mission, they are generally not sorely missed by fisherfolk and consumers. In most places fishermen and traders were far more concerned about ways to sustain and expand exploitation of Nile perch than about the negative effects for haplochromines. Lates, for all the depredation it has wrought on the small cichlid stocks, has clearly assumed prominence in both subsistence and commercial terms. To recall the words of some vetereran fishermen noted earlier in the country reviews, the disappearance of furu, the haplochromines, is not so much a problem for people as it is “a problem for the furu.”
Although the distribution of earnings from Nile perch may favour larger fishing and trading enterprises, it is nevertheless the case that the new fish supports a robust artisanal industry and is highly valued by most lakeshore folk as a moneymaker. In Tanzania the fish has earned the nickname of “saviour” because of the way it has boosted catches and earnings and provided food in greater abundance. The fact that Lates provides saleable by-products like oil and swim bladders only adds to its appeal.
5.1.4 Local Fish Processing and Deforestation
Repeated alarms have been raised about the social and environmental impacts of local preservation techniques which are commonly used on Nile perch (smoking and frying), since it is feared they are leading to widespread fuelwood shortages and deforestation around the lakeshore.
It does seem to be the case that fuelwood shortages are severe in many areas bordering on the Lake, particularly in Kenya and Tanzania, and that these shortages have been exacerbated by the growth of the Nile perch fisheries. With the exception of small juvenile specimens, the Victoria Lates, probably because of its exceptionally high oil content, does not readily lend itself to the traditional technique of sun-drying used on various other species processed around the Lake. It is possible that as feeding patterns shift in response to changes in prey stock balances, the oil content of the Victoria perch will be reduced (as observed by Ogutu-Owayo 1988). This would more readily allow processing in the manner employed around Lake Albert and elsewhere, which involves cutting the fish into long strips before drying.
Most areas around Lake Victoria are not well-served by infrastructural facilities, a circumstance that greatly curtails possibilities for distribution of fresh fish. Local processors have no other options but to employ smoking and frying if their products are to reach markets remote from the landing sites. During the mission's field visits, fishmongers themselves expressed their concern over the mounting problem of fuelwood supplies. The problem must be regarded seriously and warrants further and urgent attention, first in order to assess its true dimensions and then to assess the possibilities for its resolution.
5.1.5 Nile perch Fisheries and Socio-economic Displacement
A further area of concern amongst observers of the Lake Victoria fisheries relates to issues of employment security and resource access. It has been asserted by some critics that Nile perch is displacing or threatening to displace huge numbers of small-scale fishermen and traders due to the reduction in other fish stocks and because richer and bigger operators are coming to dominate its fishery.
Two points are involved here: displacement due to stock declines, and displacement due to economic inequalities. The Lake fisheries in general are still the domain of the artisanal operator and, in their post-harvest aspects, the artisanal processor and small-scale trader. The precise number of people who depend on these fisheries for their livelihood is not known, but for all three countries together they must amount to several hundreds of thousands. Obviously this large population would be most adversely affected by any serious drop in fish supplies, not to mention the further multitudes of consumers who would be deprived of a rich source of protein in their diets. However, as has been shown, Nile perch itself offers an optional and abundant fish supply; in switching over to exploit this fishery, small-scale operators are not displaced by the depletion of certain other species. Also, again as was emphasised before, there are indications that yields of some other fish besides Lates have not declined in recent years.
Far from destroying opportunities for fishermen, then, the proliferation of Lates has created them. The substantial growth which has occurred in fleet size and the population of fishermen since the 1970s is indicative in this regard. Some 11,000 canoes and 55,000 fishermen were reported for the late 1970s (FAO 1982). Current levels may be roughly on the order of 19,000 canoes and 70,000 fishermen (see country review sections and CIFA 1988, 1988a). If it is further and conservatively assumed that the accessory service and post-harvest sectors employ about three persons per fishermen, it can be estimated that direct employment provided by the entire fisheries now entails some 280,000 jobs, 64,000 of which have emerged in association with the Nile perch phenomenon. These are very roughly approximated figures, to be sure, and might be subject to some revision. The basic point remains the same, however: on balance Nile perch represent substantial overall opportunities gained for lakeshore communities, rather than opportunities lost or obstructed.
The displacement of poorer small-scale fishermen, artisanal processors, and petty traders by wealthier entrepreneurs and industrial firms is another question. It bears on the distribution of benefits rather than on their sheer availability.
Large-scale operators are evidently taking an increasing role in production, processing, and marketing activities, being attracted to the lucrative commercial possibilities offered by Nile perch. There are some signs in some areas that richer owners of gear and equipment secure substantial advantages for themselves while those fishermen with less means are left in a marginal position. Also, the development of trawling operations, now well underway in Tanzania waters, beginning to show in Kenya, and contemplated for Uganda, may eventually place the canoe fishery in serious jeopardy.
Preliminary evaluation by the mission suggests that the use of trawlers involves poor levels of financial performance and can hardly be justified on economic grounds. The comparative financial and economic analysis of a wooden trawler and of traditional canoes depicted in Table 5.3 indicates that for the same production level, the profitability of a fleet of about 15 canoes is about 10 times higher than that of the trawler. Employment benefit is similarly much higher when traditional canoes are used. The canoes as well exhibit a far lower foreign exchange requirement.
The Nile perch fishery has become big business in Kenya especially, where numerous firms are now involved with the processing and export of fillets to serve overseas markets. Supplies are secured directly from the landing beaches where women traders, who are the principal agents in the extensive local-level fish distribution network, also must seek their fish. There is a real possibility, not to be treated lightly, that they will be displaced as the large outside firms expand operations and/or as catch rates and total catch start declining. A related question with even wider social implications concerns overall security of access to fish by local communities. The effects of increased channelling of fish products away from the domestic consumer market cannot be gauged quickly, but it stands as an issue for immediate consideration.
5.1.6 “The Nile perch Question”: Summary and Conclusion
“Does Lates represent a boon or a bane for Lake Victoria and the people who rely on its fisheries?” This question does not lend itself to easy and unequivocal answer as the new fisheries are still in a transitional stage. Important elements of uncertainty in the situation make it difficult to predict exactly what the future holds in store.
The mission was concerned first and foremost with socio-economic or human welfare aspects of the “Nile Perch Question.” In this connection, the information collected through observation and interviews during visits around the shoreline suggests that much of the alarm that has been expressed over the presence of Lates in Lake Victoria has simply been misplaced. For example, there are strong grounds to question the views of those authorities who insist that the fish has been an “economic tragedy” and is widely resented by fisherfolk and consumers. The mission found just the opposite to be the case.
From the time of their upsurge over a decade ago, the new fisheries for Nile perch have generated enormous socio-economic benefits. The value of fish production and fisheries-related employment have greatly increased for communities around the Lake, as has the supply of fish protein. Because of Nile perch, more people are eating more fish in more places than was ever the case under the old fishery regime.
This is not to deny that there are serious or potentially serious problems associated with the Lates fishery. The mission fully recognises these, and proposes further work to characterise and address them. There is cause for concern regarding issues of equity -- the distribution of opportunities for effective participation in the fishery and of advantages to be derived. Amongst local fishermen and traders there are those who lack enough productive equipment and capital to secure a comfortable livelihood. At a more general level, the balance of interests between small-scale and industrial-scale enterprises is problematical. Displacement of some of the former by the latter appears to be a real possibility. In certain places this development could well have a particularly adverse effect on women fishmongers, who risk losing an important cash-earning activity. Any sharp decline in production levels would exacerbate matters all the more, since in that eventuality opportunities would become even scarcer and less equally distributed. Finally, the post-harvest processing and trading sector is fraught with its own special problems. Local processing methods demand great quantities of fuelwood and supplies appear to be growing critically scarce in some areas. The poor state of infrastructural development contributes to this situation because it hinders the distribution of fresh fish to markets.
Such an inventory of difficulties and bottlenecks must nevertheless be viewed in reference to the overriding advantages that have accrued as a result of Lates proliferation in Lake Victoria. On balance, Nile perch has proved a most invaluable fish in terms of human welfare considerations.
What of the other aspects to the “Nile Perch Question”? Alarms raised over the enormous loss of small cichlid species, with all its possibly grim implications for lacustrine ecology and evolutionary studies, cannot be casually dismissed. At the same time, some of the assumptions of the conservationist oriented arguments are very open to debate.
Much has been made of the productivity issue. Obviously in principle a fishery based on Nile perch and a few prey species would be far less productive than the former multispecific fishery because of energy loss through conversion to predator biomass, as emphasised by Barel et al. (1985) and Coulter et al. (1986), for example. The argument does not stand up to the realities of Lake Victoria fisheries, however. Lower protein yield for human populations has not resulted from Nile perch introductions for the simple reason that haplochromines, which formerly made up most of the Lake's ichthyomass and became the chief prey for Lates, were not significantly exploited by fishermen. On the other hand, people are now eating lots of Nile perch. The relative lack of exploitation for the haplochromines certainly protected them in former times. Their stocks are now known to be extremely sensitive to fishing pressure even at fairly low levels, as a consequence of the highly specialised patterns of adaptation and narrow habitat ranges of various component species (Goudswaard and Witte 1985).
The evolution of Nile perch into a resource base supporting a major and thriving industry was not anticipated by those who have been so outspoken in their opposition to the introduction of the species and alarmed about its presence in the Lake. Indeed, if such a Lates fishery had never developed, then perhaps the “worst case scenarios” commonly depicted in the literature would have already been fulfilled. Unfished or underfished Nile perch would have wiped out prey populations, including R. argentea and the benthic shrimp Caridina, and then turned to autopredation until the time of its own population collapse. The Lake would have then been left without major fisheries resources, and subject to severe eutrophication. It is with such eventualities in mind that some concerned scientists have issued calls to drastically reduce population levels of Nile perch through intensive selective fishing (e.g. Balon and Bruton 1986). As this report has shown, intensive fishing for Lates was well underway by the early 1980s -- not as a result of recommendations by scientific observers but as a result of local fisherfolk's adaptation to the new realities of their physical and socio-economic environments. Lack of knowledge about what was really happening on the Lake in recent years and a pre-occupation with “worst case” thinking have done much to fuel the controversy over Nile perch. It may be time now to lay such thinking to rest.
Another scenario, and in the view of the mission one that is at once more appealing and plausible, is that the Lake Victoria fisheries will in many respects follow the evolution of those of Lake Kyoga. Lates were introduced along with O. niloticus to Lake Kyoga in the mid-1950s. Both of these exotic fishes flourished in the Kyoga environment, owing in part to a substantial rise in the water level (as also occurred in Lake Victoria) during the first half of the 1960s. This rise helped the newly colonising species to thrive because “The open water area became enlarged and the productivity of the lake was increased as a result of the release of nutrients by the decaying inundated flora” (Twongo 1988). The introduction of Nile perch to Kyoga took place somewhat before their appearance in Victoria waters (Hamblyn 1960). Although there were similar species compositions in both lakes prior to the introductions, the proliferation of Lates in Lake Kyoga was far more rapid relative to the experience in Lake Victoria. It was was well established in Kyoga by the early 1960s. Ribbink (1987:10), following Ogutu-Ohwayo (1985), reviews the succession of events in this fashion:
…reports show that when L. niloticus was first introduced into Lake Kyoga the haplochromines were abundant and formed the bulk of its diet, but as they disappeared from the lake a shift in diet was necessitated. In addition to the virtual disappearance of haplochromines… [the Protopterus, Clarias, and Schilbe] which were previously abundant became rare and… fishes which were valuable to the fisheries Oreochromis esculentus, Oreochromis variabilis, and Bagrus docmac) were not encountered at all. While L. niloticus was largely responsible for the disappearance of these fishes, the contribution of everfishing and of competition of other introduced tilapiines… should not be ignored.
Thus, the fishery in Lake Kyoga was changed from a multispecific, haplochromine-based fishery to one dominated by the two introduced species L. niloticus and O. niloticus and the native R. argentea[,] with the apparent total disappearance of numerous native species from the catches.
The transformation of Kyoga fisheries, with its apparent detrimental results for many endemic species, also brought about considerable social and economic benefits. Production levels prior to the introduction of Nile perch were limited to a few thousand tons. Catches amounted to a total of 4500 t in 1956, according to Ogutu-Ohwayo (1985), who also reports that there were definite signs of overexploitation occurring as early as 1950.
As shown in Table 5.4, production levels after a period of very rapid expansion reached 100,000 t in 1973, remaining above this level through 1982. Over the entire 1961 – 1982 period, average yearly landings amounted to some 82,000 t. As noted in the Uganda country review, however, the statistics since 1976 are of very limited reliability. Therefore, in trying to establish a Maximum Sustainable Yield (MSY) estimate for Lake Kyoga after the Nile perch introduction, it may be better to fix upon the more conservative figure of 50,000 t per year, which is around the average annual catch for the period 1961–1975. This MSY estimate will be used for purposes of comparison with the Lake Victoria situation, to be considered below. The point to be noted here, though, is that even with reference to conservative catch returns over the years, the introduction of Nile perch into Lake Kyoga has been quite a major and prolonged success from a socio-economic viewpoint.
With R. argentea remaining almost completely unexploited, the catch from Lake Kyoga has until a few years ago been about equally divided between Lates and O. niloticus. The significant decline in Nile perch catches observed by researchers (IFAD/World Bank Project) since 1983 has raised questions about the viability of the fishery, and cannot be overlooked. As indicated in the country review section, the main factors in this decline seem to be the application of excessive effort (resulting from a sudden increase in gear availability due to fisheries rehabilitation projects) from 1983 coupled with the use since 1976 of very destructive fishing practices and a slow but persistent drop in the water level. It is clear from the Kyoga experience that Lates stocks are rather sensitive to overexploitation. This point has also been made in connection with the situation in Lake Tanganyika (CIFA 1987a). As with other fish stocks, Lates needs to be managed with care and foresight.
The evolution of the ichthyomass of Lake Victoria so far seems basically to be following the pattern that developed in Lake Kyoga until the disruptions just described. The Victoria Nile perch initially preyed heavily on haplochromines, but has now switched to feed mainly on R. argentea as well as the freshwater shrimp Caridina. As reflected in the species composition of landings in the Lake and in Kenya particularly, Lates, O. niloticus, and R. argentea are becoming predominant, with notable reductions apparent in the abundance of certain native species, at least in the inshore areas.
In relation to the possible evolution of Lake Victoria fisheries, Ribbink (1987:11) reviews the parallel course of developments in the fisheries of Lake Kyoga and the Nyanza Gulf in Kenya, and comments that:
If the trends shown in Lake Kyoga and in the Nyanza Gulf of Lake Victoria are repeated within the whole of Lake Victoria then virtually all the haplochromines and most other native fishes will disappear from the catches. In Lake Kyoga and in the Nyanza Gulf, L. niloticus, R. argentea and the introduced tilapiines are effectively the only fishes in the catches…. Thus a possible end point would be a fishery based on R. argentea and L. niloticus. This may be sustainable as prey productivity is great, [and] the difference between prey and predator turnover considerable… [Since] man will catch predators as well as prey, it is possible that the prey biomass will sustain fairly high levels of exploitation. Such a fishery would be similar to the clupeid-centropomid fishery of Lake Tanganyika…. A viable tilapiine fishery based on the introduced species may also remain.
As remarked above, a three species Nile perch-dagaa-tilapia fishery has been able to sustain high levels of production on Lake Kyoga. In Lake Victoria, Lates also feed heavily on Caridina, and the abundance of these small shrimp has been increasing substantially in recent years according to the trawl surveys carried out by HEST in the Tanzania sector (Wanink, Ligtvoet and Witte 1988). This development further strengthens possibilities for sustained Nile perch fisheries in Victoria waters.
Significant differences exist between the two lakes, however, and must be taken into consideration. Kyoga covers an area of 2700 km2 and is very shallow, with an average depth of 3 to 4.5 m, meaning that exploitation is feasible across its entire surface. Lake Victoria is both very much larger (68,000 km2) and deeper (mean depth 20 m). For comparative purpose and taking into account that tilapia and Nile perch are found and caught predominantly from the nearshore areas of Lake Victoria, it can be assumed that the major productive waters and/or fishing grounds are confined to the 20 m or less depth zone for Nile perch (an area of some 12,700 km2 or 18.4% of the Lake) and to half this area (6350 km2) for O. niloticus.
For a conservatively estimated MSY of 50,000 t a year, Lake Kyoga exhibits a very respectable yield of 18.5 t per km2, equally divided (9.25 t each) between Nile perch and O. niloticus. Applying the same yield levels to the nearshore zones defined above for Lake Victoria, an annual 9.25 t/km2 rate gives an estimated MSY of about 120,000 t for Lates and 60,000 t for O. niloticus. For demersal resources, a total MSY of 180,000 t, or even up to 200,000 t (assuming the contribution of other demersal species), would be lower than the pre-Nile perch fishery regime estimate of about 223,000 t (CIFA 1982). It would however be far more easy and profitable to exploit. The old haplochromine resources may have been immense, but it is extremely doubtful that their commercial significance could have amounted to very much (cf. Ogutu-Ohwayo 1988). Haplochromine stocks are known to be extremely fragile in the face of exploitation, and they are difficult to harvest profitably because greater depth ranges are often involved. They also have a history of low consumer demand, a fact which led to their being trawled for in Tanzania for the uneconomic production of fishmeal.
The impressive development of the pelagic resource in Lake Victoria must also be borne in mind. R. argentea has grown into a fishery of outstanding promise, with total lakewide landings likely to be in the range of 50,000 t in 1986/87. The increasing abundance of the dagaa obviously further provides for the sustainability of Lates stocks.
The foregoing comparison between the fisheries of lakes Victoria and Kyoga is admittedly of a tentative nature. There are many complex factors which would also have to be taken into account in constructing a more thorough and conclusive assessment of the trends and prospects involved. Yet the comparison allows some grounds to suppose that a total annual catch of around 250,000 t might be sustainable for Lake Victoria in the foreseeable future. This would mean an average lakewide yield of 3.6 t/km2: not particularly high for a shallow lake of its type, and only about half the yield of Tanganyika, a very productive and far deeper lake which supports a similar predator-prey fishery regime.
If the Lake Victoria fishery resource can indeed sustain such a level of production, then the presence of Nile perch in these waters will continue to bring remarkable benefits to the three riparian countries, just as it has done for more than a decade. The sustainability of this resource, however, will depend crucially on careful, well-informed management policy and its effective implementation. Resource fluctuations may be anticipated. Stability in the sense of static or finely tuned stock balances will probably not be a feature of the evolving situation. Predator-prey relationships are likely to undergo a continual process of adjustment and resolution in relation to environmental factors and the dynamics of fishing effort.
It is stressed again in conclusion that the mission regards the presence of Nile perch in the Victoria fisheries as an exceedingly positive development from a human welfare standpoint. Strong evidence exists to support this claim. The fish represents enormous food and cash resources to multitudes of people living around and even well beyond the lakeshore. Against these substantial community benefits must be weighed the apparent loss or serious decline of many endemic fish species, especially amongst the haplochromine cichlids. Whether such ecological disruption constitutes a “tragedy” in itself is a question that the mission cannot appropriately address. But it is surely possible to take conservation concerns into meaningful account as policy and management for the Lake Victoria fisheries are further developed. In terms of such future policy and management development too, the mission finds that additional and far more through pilot study work is urgently required on many of the socio-economic issues and problems that attend the Lates succession in the Lake. Recommendations along these lines are spelled out in the final section.
5.2.1 General Considerations
Recent events of change in the fisheries of Lake Victoria warrant utmost attention because they affect resources of critical importance to the food and employment security of multitudes of people dwelling in the three riparian states. The dramatic transformations in species balances and attendant vast increases in overall production levels must be carefully scrutinised and understood through stock assessment surveys if the resource base is to be utilised and sustained in optimal ways. Aside from planning and management imperatives, the Lake fisheries call for close attention as an extraordinary case study of the effects of new species introductions.
In addition to the basic need for stock assessment and prediction, specialists have noted a number of gaps in current knowledge of Lake Victoria fish ecology and biology. For the Nile perch particularly, more information is needed regarding habitats, interactions with prey species, and breeding behaviour, for example (see Bwathondi 1985; Coche and Balarin 1982; HEST 1986; Kudhongania and Twongo 1985; Okemwa 1985).
It is also clear, as has been repeatedly stressed by fisheries professionals and administrators in the past, that statistical collection and reporting systems for the Lake need to be improved in order to provide on a continuous basis more reliable data to monitor catches and effort (see Bernacsek 1986; Coche and Balarin 1982; CIFA 1987; HEST 1986; Okemwa 1985).
Despite various deficiencies, biological, ecological, and technical aspects of the Lake fisheries have received considerable attention in comparison to human welfare issues. In relation to the Nile perch phenomenon especially, much of the observer commentary on impacts and potentialities vis-a-vis fishermen and the wider population seems to be based on indirect reports and conjecture -- all in the absence of through study and documentation. This is a much neglected field of inquiry, even though development planning and management efforts must be supported by socio-economic perspectives in order to be most effective.
5.2.2 Resource Evaluation and Management
The last regional effort to assess the fisheries resources of Lake Victoria in a systematic way was undertaken through the EAFFRO with the assistance of FAO in 1969–71. Since then, the major national research organisations (KMFRI, TAFIRI, UFFRO) have pursued independent research programmes but their effectiveness has been much impaired by the lack of financial resources as well as other constraints. The Netherlands-funded HEST project affiliated with TAFIRI has mounted the most ambitious of these localised stock assessment exercises and it is hoped that this activity will be continued beyond 1988.
Following repeated recommendations by the CIFA Sub-Committee for the Development and Management of the Fisheries of Lake Victoria, a regional project for coordinated stock assessment in the three countries is to start in 1988 with funding from the EEC. Work is to focus on trawl surveys and complementary training. Assistance will also be provided in the study of fish biology and ecology and in the improvement of fisheries statistics.
Overall, it is anticipated that these efforts, together with further initiatives to strengthen statistical services and investigate socio-economic aspects of the fisheries, will provide the information base required for sound management.
The mission is of the opinion that various steps should be taken immediately in regard to management of the Lake fisheries:
Gillnet Fisheries: Tanzania and Uganda
The fisheries of Tanzania and Uganda have been expanding quite rapidly and resource evaluation needs to be carried out to determine how much additional effort, if any, they can absorb. In the meantime, it is recommended for the gillnet fisheries in particular that expansion not be encouraged further, whether through development projects, input subsidy programmes, or other means.
Gillnet Fisheries: Kenya
The gillnet fisheries of Kenya already are showing definite signs of localised over-exploitation (at least) in the form of: depressed catch rates within the waters of the Nyanza Gulf; a growing demand for gillnets of smaller mesh size, and increasing use of longlines -- a more economical gear when catches are less abundant. It is therefore recommended that further development of the industrial Nile perch processing capacity be discouraged, perhaps through means of licensing restrictions.
It would furthermore be desirable to discourage as soon as possible the progressive reduction of mesh size as well as to limit the total fishing effort applied in the gillnet fisheries. Direct control of artisanal effort is one way of preventing overexploitation while preserving good economic returns. Experience has shown, however, that it is extremely difficult to implement because it requires a monitoring, control, and surveillance capacity which is costly and usually, as in the present case, unavailable. In view of this, urgent steps are needed to help devise alternative means of controlling effort, with an emphasis on participatory approaches. Community-group based licensing schemes are one possibility warranting investigation.
Stringent control or outright prohibition of beach seines should be urgently implemented in light of their destructive and economically wasteful impact on juvenile Lates and O. niloticus as well as other species. Beach seining was banned in Uganda in 1987 without serious economic repercussions on the fishermen, although a more appropriate procedure would have been to give seine owners a deadline allowing enough time to fully recover their investment. The problem is more acute in Kenya and Tanzania, where beach seining supports a more important industry due to higher demand for small sized fish. It is understood that a ban is now being planned by the Kenya authorities.
Stringent control or outright prohibition of trawling should also be seriously considered. In the absence of proper monitoring, control, and surveillance capabilities, trawlers are all too likely to operate in the same fishing grounds used by small-scale fishermen. As discussed above, there are strong indications that trawling provides limited financial returns and is far less economically beneficial than gillnetting with traditional canoes.
5.2.3 Fisheries Statistics
As stressed in this report and by a number of authors in the past, statistical collection and reporting systems around the Lake are in serious need of improvement. The case of Uganda is particularly critical due to the prolonged period of civil unrest experienced there in recent years. Major rehabilitation efforts are needed before the fisheries administration of the country will once again be able to operate effectively.
Most of the deficiencies which have been identified in fisheries statistical services concern the mechanisms of data collection and processing operations more than the methods used. However it should be noted that the pattern of separately assessing fishing effort and catch per species seldom allows for the reliable estimation of CPUE when the information systems are not functioning well. Efforts should be organised to collect CPUE statistics directly for specific fishing units.
It remains that the basic impediment to the production of good fisheries statistics is the lack of financial resources. This is expressed in manifold ways: insufficiently trained and remunerated recorders and supervisors, and consequent poor levels of job performance and motivation; lack of logistical support at the field level; lack of adequate data processing capabilities; and inadequate data quality control procedures. Financial constraints ultimately can hinder the ability of administrators to keep track of the most fundamental developments in the fisheries. For example, yearly censuses of canoes and fishermen have been neglected or inadequately carried out in the past due to these constraints.
A project was prepared in the context of this mission to upgrade the fisheries statistical systems and provide complementary socio-economic information to facilitate development and management of resources in Uganda, with particular focus on Lake Victoria. UNDP will be financing this two-year project which will be executed by FAO beginning in 1988. In Tanzania UNDP is also expected to fund a nation-wide project with rather similar aims. Finally, it is expected that the aforementioned EEC project will provide additional support to all three countries in this area.
The fishing industry all around the Lake has shown remarkable dynamism in recent years, and the inadequately known state of the resource does not justify any major development interventions at this stage. As far as the harvest and post-harvest sectors are concerned, however, the mission recommends the following:
R. argentea in Uganda
Technical and economic investigations should be undertaken to assess the possibility of developing the fisheries for R. argentea in Uganda. Such work could be carried out as part of the UNDP/FAO project described above.
The operations of the local fishnet manufacturing firms in Mwanza and Kampala have been curtailed in the past due to lack of foreign exchange allocations. It is recommended that plans be drawn up to allow these firms direct access to foreign exchange so that they can negotiate directly for import supplies, rather than having them imported by government or donor projects.
Significant economic gain can be expected from the improvement of basic infrastructure around many parts of the shoreline. This is particularly true for the Tanzania and Uganda sectors. Feeder roads are often in extremely poor shape and subject to seasonal flooding. Landing sites and fish markets need upgrading through the provision of sheltered platforms and running water supplies.
Fish smoking practices could be substantially improved through the introduction of more fuel efficient techniques such as the Chokor oven (UNICEF 1983), which has already been tested successfully in both Uganda and Kenya. Widespread adoption of this technique would depend very much on the price of fuelwood, as determined by its scarcity. The establishment of open-sided shelters over smoking ovens would allow for continuous operations during the rainy seasons. Further investigation of processing and alternatives to current practices is proposed by the mission.
Possibilities for export of Nile perch to hard-currency markets should be assessed for Tanzania and Uganda. The export trade is well developed in Kenya, though it seems doubtful that fresh fish production from national waters can be sustained at present levels. The Kenya industry may already be depending on fresh fish supplies from Tanzania and Uganda to some extent. The development of limited export trade in Tanzania and Uganda could conceivably bring in much-needed foreign exchange without adverse effects on local supplies, which seem plentiful at the moment. Both countries, however, face significant organisational and logistical obstacles when it comes to export development. Further assessment is therefore recommended before such trade is encouraged.
5.2.5 Socio-economic Aspects
Based on the preliminary assessment of this report, it is evident that a considerable array of interrelated issues and questions concerning the socio-economic effects of the Nile perch presence in Lake Victoria stand in need of much more through investigation. These are listed in summary fashion below. The significance of particular issues may very between the three countries, but in general the agenda for research and development action are quite similar, and can be considered under a common framework.
Artisanal Fishermen and Their Technology
It is generally apparent that local fishermen have rapidly responded to the Nile perch boom with gear adaptations and adjustments in fishing strategies. But important characteristics of the artisanal sector remain poorly known, beginning even with the simple extent of the fishing effort (numbers of operators, boats, and gear). Other information essential to the formulation of sound management policy needs to be collected for such topics as: conditions of entry and access to productive equipment in the fisheries, distribution of ownership and employment benefits, financing and investment patterns, linkages to post-harvest activities, attitudes towards fisheries management, and the feasibility of alternative management schemes.
Women's Participation in the Fisheries
Though women play an important and frequently leading role in the processing and marketing of fish around the lakeshore, detailed understanding of their contributions is lacking. The growing abundance of Nile perch has certainly had a profound impact on the fish trade, but the ways in which local women and their households have been affected by this development, and the prospects for their continued participation in the post-harvest sector, stand in need of much fuller appreciation. The mission identified potentially serious conflicts emerging between the interests of small-scale processors and traders and those of the larger industrial concerns.
Fuelwood Issues and the Post-Harvest Sector
Urgent attention is required to gauge the severity of fuelwood depletion and deforestation around the Lake, particularly in relation to the heavy resource demands of the artisanal fish processing business.
Evaluation is needed of the socio-economic feasibility of alternative processing techniques, such as improved forms of sun-drying and the use of more efficient smoking kilns.
The potential for expanded domestic and commercial use of Nile perch by-products (oil, skins, swim bladders, and skeleton frames after filleting) requires fuller evaluation.
Local Consumption and Nutrition
Further basic research is needed around the lakeshore on changing patterns of fish consumption and availablity, and their underlying factors and nutritional implications for local communities. A better understanding of consumer habits within the the coastal fringe and of marketing and distribution across wider areas would allow further assessment of the likely impact of development and management measures on consumption and trade.
Of related and special importance is the need for closer examination of the rapidly expanding long-distance trade in sun-dried R. argentea. This trade apparently now extends across wide areas of East and Central Africa. Its further development can have a significant impact on the fisheries of other areas and of Lake Tanganyika especially. Dagaa comprise the major fishery of Lake Tanganyika, yet it is known that significant amounts of dried Victoria dagaa are presently being sold around the eastern shoreline and hinterland of the Lake and even in Kigoma.
Larger Commercial Ventures
The growing involvement of wealthier entrepreneurs and industrial firms in the Nile perch fisheries at both the harvest (trawling operations) and post-harvest (processing and export to non-African markets) levels constitutes an additional outstanding area for priority investigation. It is crucial to understand more fully the extent to which larger commercial ventures are financially and economically viable and may operate without jeopardising the artisanal fisheries, and without adversely affecting the supply of fish for local markets.