Fishing community preferences and willingness to pay for alternative developments of ecosystem‐based fisheries management (EBFM) for Lake Naivasha,Kenya

Ecosystem‐based fisheries management (EBFM) is an important complement to existing fisheries management approaches to maintain ecosystem health and function; to translate goals and aspirations for sustainability into operational objectives, the preferences of the fishing communities should be considered for successful implementation of EBFM. This study analysed the preferences of the fishing community for alternative EBFM developments for Lake Naivasha, Kenya, and estimated the willingness to pay, using a choice experiment approach. Protection of fish breeding grounds, improving tilapia fish abundance and accessibility of fishing zones were identified as relevant EBFM attributes for the choice experiment. A monetary attribute (payment for fishing permit) was also included. In addition to a conditional logit model, mixed logit models are estimated to account for heterogeneity in preferences. This study results indicated fishing communities are most concerned about tilapia fish abundance and protection of fish breeding grounds. The welfare measures reveal that members of the Lake Naivasha fishing community are willing to pay a considerable sum of money for ecosystem services improvement, relative to their low income derived from fishing. These study findings highlighted that evaluating the preferences of the fishing community and valuing the fishery at an ecosystem level are vital to prioritize and choose between alternative interventions for sound implementation of EBFM.     

Impacts of the Victoria Nile Bujagali hydropower dam on fisheries and livelihoods

The Upper Victoria Nile (UVN) flows from Lake Victoria into Lake Kyoga, spanning 117 km and supports a diverse aquatic fauna that sustains livelihoods of riverside communities. The UVN is habitat to critically endangered (Labeo victorianus), near threatened (Oreochromis variabilis and Oreochromis esculentus), and rare species (Neochromis simotes). Four hydropower dams were built on the UVN to provide energy for industrial and socioeconomic development, notwithstanding consequential environmental and socioeconomic impacts. The impacts of Bujagali hydropower (BHP) dam on fisheries and livelihoods were assessed biannually (April and September) from 2006 to 2019, using fishing effort, species abundance, catch composition, and economic beach revenue at upstream, mid-reservoir, and downstream transects. The fishing boats increased from 31 in 2009 to 293 in 2019 and fishers from 83 to 500 over the monitoring period. Maximum annual catch of 461.4 t was recorded in 2014 and lowest of 54.2 t in 2009. In all transects, Protopterus aethiopicus and Labeo victorianus were least in the commercial catches and the use of Mormyrus kannume juveniles as bait for Nile perch fishery corresponded with increased catches from 3.3 t in 2009 to 148.2 t in 2019. Women were mostly engaged in post-harvest activities such as fish drying, smoking, and food vending. These observations suggest coupling effects of the hydropower dam and ineffective fisheries management. The harvest of M. kannume wild stocks for bait should be banned and research in possible domestication of the species undertaken. There is a need to strengthen fisheries enforcement to curb illegal effort and overexploitation and to implement conservation actions to mitigate potential biodiversity impacts from the hydropower dam operations.     

Effects of flood control and drainage on fisheries in Bangladesh and the design of mitigating measures

Inland capture fisheries (open-water systems where naturally occurring fish are caught) are one of the main sources of animal protein in Bangladesh, and are an important sector of the economy. There is growing concern that flood control and drainage (FCD) projects have severely reduced fish stocks by reducing wetland areas and by blocking fish migration and dispersal routes. Results of surveys in 17 projects completed between 1970 and 1989 were consistent with this trend and show that projects with serious effects on fisheries may not be economically viable. However, a general decline in catches resulting from overfishing may also be a factor. The Bangladesh flood action plan forms a framework for accommodating mitigation of FCD effects on fish in the planning of future projects. Controlled flooding provides an opportunity to manage capture fisheries. Two types of measures are discussed: protecting wetlands within projects by building bunds to retain water during the dry season; and designing regulators that are operated to let adults of the commercially important but declining major carp escape to reach their spawning grounds, and which allow the passage into the projects of the surface layers of water containing spawn and fry of the same species during the monsoon peak. Projects can be planned and designed to be ‘fish friendly’ using such measures, but this will only be effective if they are managed and operated in ways that are consistent with this objective. This requires the active involvement of local fishing communities, and reconciliation of conflicting interests between farmers and fisherfolk. © 1997 John Wiley & Sons, Ltd.     

A Comment on the Paper by John r. M. Kelso and Gary s. Milburn: “Entrainment and Impingement of Fish by Power Plants in the Great Lakes Which Use the Once-Through Cooling Process” (J. Great Lakes Res. 5:182-194, 1979)

Assessment of entrainment and impingement impact of the 89 steam-electric generating stations on Great Lakes fish stocks reported by Kelso and Milburn (1979) is evaluated. Despite the large number of fish impinged at these stations, impingement losses typically constituted less than 1% of the standing stocks of fish in the lakes. Similarly, entrainment losses also represented a small fraction of total larvae in the lakes. Therefore, power plants alone probably have minimal impact on the Great Lakes sport and commercial fisheries and no detectable impact on fish populations. Despite Kelso and Milburn's assertion to the contrary, future fish losses from proposed generating capacity expansion may be less, due to improvements in cooling water intake design.     

Lake Victoria fisheries: Outlook and management

The past subsistence of the Lake Victoria fishery was dominated by rich, diverse haplochromine cichlids. This multispecies fishery has undergone a decline over the past four decades, evolving into a commercial fishery consisting mainly of Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus) and cyprinid (Rastrineobola argentea species). To better understand Lake Victoria fisheries, studies dating as far back as the 1920s have been carried out to assess the status of the fish stocks. These past studies indicated the lake fisheries were declining because of numerous major challenges, including intense fishing, invasive species, loss of biodiversity, ecological alterations, climate change, inadequate information to inform management and unharmonized policies. Numerous policies and regulations have been developed and implemented over the years to address these issues and manage the fisheries sustainably. Most of the interventions have been sectorial, disjointed and unharmonized and have not reduced the declining fish catch rates. With reestablishment of the East Africa Community (EAC) with several institutions in 1994, the Lake Victoria riparian states initiated an ecosystem approach to manage the Lake Victoria fishery resources in a sustainable manner. This study reviews the development of the Lake Victoria fisheries, outlines major past and present management challenges and provides a set of new strategies to manage the lake's fisheries resources, with emphasis on an ecosystem approach.     

Difficulties of fishing at Lake Naivasha,Kenya: is community participation in management the solution?

Unlike other lakes in tropical regions, Lake Naivasha exhibits low fish species diversity. The fishery is based on introduced fish species that are not native to the lake. The lake ecosystem is very fragile, as reflected in its fluctuating fish catches. The fishery almost completely collapsed in 2001, due partly to mismanagement and ignorance about needed conservation measures. The Kenyan government, like many governments around the world, recognized the need to involve fishers and other stakeholders, in order to ensure better management of the lake fisheries resources. Also referred to as collaborative management (co-management), this management approach provides the opportunity to share responsibility for managing the fishery resources between the government and the community. A total ban on fishing was imposed in February 2001, lasting for 1 year, to allow lake fish stocks to recover. This study analyses the co-management process for Lake Naivasha, and discusses the role played by the community during the fishing ban, as well as the successes and challenges encountered, and the tribulations and perceptions of the fishers regarding the new management strategy. It also comprises the first documentation of community participation in fisheries management begun for Lake Naivasha in the year 2001.     

Spawning and recruitment patterns of major fish species in Bontanga Reservoir, Ghana, West Africa

The spawning and recruitment patterns of the major Cichlid fish species, including Hemichromis fasciatus, Oreochromis niloticus, Sarotherodon galilaeus, Tilapia zillii and other species, Auchenoglanis occidentalis, Brycinus nurse, Clarias gariepinus and Marcusenius senegalensis were studied for 24 months in Bontanga Reservoir, Ghana, using length‐based fish stock assessment approaches. The species spawned throughout the year, with two spawning pulses described as major and minor spawning seasons. The major spawning season occurred from March to September for the Cichlids, and from May to September for the other species. The minor spawning season, indicative of extended spawning, occurred from October to March for all the fish stocks. Fish spawning began with the onset of the rains in April/May, peaking by June/July, before the rainfall peak in August for all the fish stocks studied. Recruitment was found to occur throughout the year, with major and minor pulses coinciding with the major and minor spawning seasons. Accordingly, the most appropriate time for a possible closed fishing period appears to be from June to August, 1 month after the start of, and before the end of, the rains. The estimated mean standard length (L_m) for first time spawners of A. occidentalis, B. nurse, C. gariepinus and H. faciatus were 11.7, 12.7, 2.7 and 7.5 cm respectively. The estimated maturity–length ratio of 0.4 and 0.2 for O. niloticus, S. galilaeus and T. zillii were lower than the known 0.7 for normal growth, suggesting the tilapias matured faster, and at a smaller size, in the reservoir. Apparent sexual precocity associated with early maturity, year‐round spawning and recruitment were some important adaptations found to have sustained the reservoir fisheries, even during high fishing pressures. For conservation and sustainable exploitation of the fisheries, instituting a closed fishing season, mesh size regulations, withdrawal rights and a community‐based fishery management system are recommended.     

Turbidity control and fisheries enhancement in a bottomland hardwood backwater system in Louisiana (U.S.A.)

In response to a noticeable decline in recreational fishing in the formerly productive Larto—Saline backwater complex of east central Louisiana, a study was begun to identify causative factors for the decline and to determine effective methods to remedy the problem. To this end, water quality and fisheries surveys were conducted in the system for the study period 1 July, 1981 to 30 June, 1989. Data collected during the early years of the study indicated chronically high turbidity (> 100 FTU) to be the major factor limiting game fish production. The high turbidity can be related to man-made alterations of natural flood patterns that had changed the major source of backwater flooding from Black River to the highly turbid Red River. In September, 1986, a construction project was undertaken to restore flood patterns to approximate natural conditions. Sampling subsequent to this construction has shown a significant decrease in turbidity and an increase in game fish production.     

The natural history and fisheries ecology of Lake Chilwa,southern Malawi

Lake Chilwa produces between zero and 24,000 metric tons of fish per year, making it one of the most productive but variable lakes in Africa. The size of the lake varies seasonally and among years, sometimes drying completely. Its surrounding wetland and floodplain provide habitat for a diversity of birds and economically valuable grasses and reeds. When the lake has water, there is considerable activity on its shores and temporary fishing villages spring up. People move in and out of the lake basin in concert with these seasonal and longer term changes. This paper examines the environmental dynamics of Lake Chilwa and its surrounding wetlands, presents an overview of the socio-economic context of the area and discusses threats to this resilient system that might occur as a result of climate change. We conclude that management of Lake Chilwa must place the lake in the wider economic and ecological system in which it is situated. Ultimately, land-use practices within the basin present more of a threat to the resilience of the fishery and people's livelihoods than overfishing or a strict focus on the lake's resources. These perspectives present significant challenges to conventional fisheries governance.     

Challenges to sustainable management of the lakes of Malawi

This paper reviews the management challenges facing Malawi lakes and analyzes the management responses that have been developed to deal with these challenges. Malawi lakes are under considerable stress due to high population growth and increasing levels of poverty which have led to overexploitation of fishery resources. High rates of soil erosion in the lake catchments are increasing siltation of shallow lakes, deltas and embayments, affecting water quality and fish breeding habitats, thereby degrading fish production potential. This review further shows that past and current management approaches have focused on maximizing sustainable yield and have failed to adequately incorporate socio-ecological factors and broader lake catchment processes into fisheries management plans. This, in turn, led to the top-down development of fisheries laws and technical regulations which were difficult to enforce, increased conflict between resource users and fisheries managers, and failed to control fisheries over-exploitation and the collapse of the chambo (tilapia) and cyprinid fisheries. The paper recommends that the fisheries policy should be reviewed to focus on resilience of fisheries, environment and livelihoods. Policy makers should adopt integrated management planning to address the diverse interest of stakeholders in lake basins, as well as the ecological, socio-economic and external factors threatening sustainability of lake ecosystems and livelihoods of dependent communities.     

Fisheries ecololgy and management of the Jaraqui (Semaprochilodus Taeniurus,S. Insignis) in central Amazonia

The decline of heavily exploited stocks of large, high quality, food fishes in central Amazonia has led to increasing fishing pressure on smaller taxa, especially the jaraqui (Semiprochilodus spp.). The Prochilodontids, now the most important species to the fisheries, are seined by commercial fishermen during three distinct peridos. At the beginning of the annual floods, schools of mature jaraquis in poor-water tributaries migrate downstream to spawn in the nutrient rich white-water rivers. During these rapid spawning runs, fishing effort is concentrated in the lowermost reaches of the tributaries. After spawning, they return in small groups to feed intensively in the flooded forest of the same tributaries from which they had migrated. This period, of approximately three months, may be considered as a natural closed season to the fisheries. The dispersal migration is most complex and requires distinct fishing strategies. In the middle of the floods large schools of fat jaraqui descend from the tributaries to the white-water rivers again. From there, they move upstream to different poor-water tributaries. As downstream movements are more diffcult to observe, fishermen remain at fixed fishing grounds. This contrasts with the dynamic strategies of the subsequent upstream fishing period which contributes 60 per cent of the annual catches. Fluctuations in catch are shown to reflect year to year variations in abundance, which are linked to the hydrological cycle. Considering that fishing over the stocks of jaraqui has already more than compensated for the deficit in catch of larger species, a combination of increased effort and environmental problems could lead, in a short period to a depletion of one of the most profitable fisheries of central Amazonia. Regulation of the fisheries could benefit from a more reasonable distribution of effort among other migratory illiophagous species which remain unexploited, if the goal of sustainable yield and conservation of these stocks is to be achieved. Reserved waters in large strategic units of at least 300 km along white-water rivers (which is equivalent to the maximum upstream displacement of jaraqui during their dispersal migrations) could also be useful to compensate for the loss of floodplain areas due to deforestaion, river regulation, use of pesticides, and mining. River impoundments in tributaries in central Amazonia may have little effect on jaraqui stocks, as spwning movements are unlikely to be directly interrupted by dams. However, alterations of the hydrological regime may also benefit from simulation of the flood cycle to mitigate potential negative impacts.     

Potential for fisheries-induced evolution in the Laurentian Great Lakes

Fisheries are selective, capturing fish based on their body size, behaviour, life stage, or location. Over time, if harvest pressure is strong enough and variation in traits heritable, evolution can occur that affects key aspects of the ecology of fish stocks. Most compelling examples of rapid evolution in response to harvest have come from marine systems. Here, we review the state of knowledge on fisheries-induced evolution (FIE) in the Laurentian Great Lakes where subsistence, commercial, and recreational fisheries have operated for centuries. We conclude that stocks experienced harvest rates high enough and for long enough to undergo evolution. While historical fisheries exploited more juveniles, some contemporary Great Lakes fisheries target primarily adult size-classes thus reducing current selection for earlier maturation; however, other traits and behaviours could evolve (e.g., growth, timing of spawning, boldness). While commercial harvest previously dominated, recreational fishing is now expected to be a strong contributor to harvest selection in the Great Lakes. Environmental variation, density-dependence, invasive species, and the genetic legacy of population bottlenecks and stocking interact with, and make it more challenging to detect, FIE in the Great Lakes than in marine systems. Case studies are presented for Great Lakes stocks of yellow perch Perca flavescens and lake whitefish Coregonus clupeaformis for which FIE has been investigated. The evidence for FIE in the Great Lakes is currently sparse, potentially because of the low research focus on this topic or because of the interacting influence of environmental variation and anthropogenic stressors.     

Taxonomic status of fish parasites in Kenyan inland water systems and their significance on the freshwater fisheries and aquaculture productivity within the region

Fish are a resource with great economic, nutritional and recreational benefits to humans on a global scale. In Kenya, fish represent an important source of food and income through trade and employment to many communities. In fact, fish are an important alternative source of animal protein, especially in famine‐tolerant arid and semi‐arid regions such as Turkana, Marsabit, Pokot and Baringo Counties, where annual drought periodically hampers traditional livestock keeping destitute. Kenya freshwater fishes have remained vulnerable to a variety of parasites and related diseases. Approximately 119 fish parasites have been reported in the country, with about 83 being identified to species level and 35 to genus level. Out of the reported parasites, 77% were detected in wild fish, 8% in farm fish and 15% in both wild and farmed fish. The parasites identified by various studies include protozoa (7), myxozoa (7), nematode (20), monogenean (33), digenean (16), cestoda (15), acanthocephalan (6) and crustacean (15). The highly commercialized fishes, such as Oreochromis niloticus and Clarias gariepinus, harbour the highest number of parasites, which greatly hinder fisheries and aquaculture productivity through retarded growth, mechanical damages, reduced reproduction rates and increased mortality of the fish hosts. Thus, there is need for adequate information on the taxonomy and ecology of these parasites as a basis for developing appropriate management and policies to control them. This review article is meant to provide an overview of the distribution, occurrence of fish parasites and their impacts on inland water fisheries and aquaculture in Kenya, while also highlighting the available gaps warranting further studies, with the goal of developing appropriate and accurate control measures to improve the region's fisheries and aquaculture productivity and food security.     

Comparison of community-based adaptation strategies for droughts and floods in Kenya and the Central African Republic

ABSTRACT

This paper discusses community-based adaptation strategies for droughts and floods in small watersheds in Kenya and the Central African Republic. Survey data on adaptation strategies and annual rainfall data in the watersheds were used to assess the occurrence of floods and droughts, and their impacts. In both areas, the main adaptation strategy for floods is temporary relocation. For droughts, changing livelihood activities was the main adaptation strategy, while relief-seeking applied to both droughts and floods. We recommend greater preparedness, capacity building, and the diversification of livelihoods as means of enhancing adaptation.     

Artisanal and commercial fishing gear and practices in the Lake Victoria basin drainage systems of Kenya: A photodiagrammatic verification

This study focused on providing a photodiagrammatic database illustrating various types of fishing gear and practical skills currently used in artisanal and commercial fishing in the shoreline, nearshore and offshore areas drainage systems of Kenya in the Lake Victoria drainage basin. It also identified the fish species typically caught by the fishing gear, and the gear catch per unit effort and selectivity. Four artisanal fishing gears (spear, trap, basket and hook) and two commercial gears (mosquito seine and purse seine) are used to fish in shoreline areas. Five commercial fishing gears (gill net, parallel tennis net, semicircular‐tennis net, sett net, long line) are used to fish in nearshore areas, while two commercial gears (drift net and offshore seine net) are used in offshore areas. For artisanal fishing, the basket is the most efficient gear for catching six fish species. The mosquito seine is the most efficient commercial fishing gear for catching 22 fish species. There is evidence for a chronological shift to more efficient artisanal and commercial fisher handmade fishing gear, resulting in overexploitation of diverse fish species. At the same time, the licensing and management policies for the use of various fishing gear are unclear, suggesting re‐evaluation of policies to cater for the use of handmade fishing gear.     

Benefits and Costs of the Ruffe Control Program for the Great Lakes Fishery

Although data on Great Lake fish stocks and values are uncertain estimates, reasonable approximations can be made concerning economic losses for the United States from various types of management practices. Based on biometric changes that are projected to occur, it appears that early control of a non-indigenous fish species, specifically ruffe (Gymnocephalus cernuus), can result in significant investment returns. By instituting a ruffe control program, benefits to the public will exceed costs by 44 to 1 over the next five decades. Under a moderate case projection of benefits this will yield an estimated net public savings of $513 million for the United States. Since sportfishing values are much greater than commercial fishing values, anglers will benefit the most from this program.     

Analysis of the technical efficiency of Nile perch (Lates niloticus) fishers in the Tanzanian portion of Lake Victoria: A stochastic frontier analysis

The Nile perch fishery sector in Tanzania is important for enhancing the livelihoods and food security for the majority of people living near the Tanzanian portion of Lake Victoria. Despite continued government efforts and other institutions, including the Food and Agriculture Organization (FAO), Lake Victoria Fisheries Organization (LVFO), European Union and World Bank regarding the management of Lake Victoria, the Nile perch fishers have remained relative inefficient in regard to improving their fish catches. The Nile perch small‐scale fisheries sector in particular faces a challenge regarding how to improve production performance while, at the same time, ensuring a sustainable level of fisheries resources. This reality necessitates the measurement and analysis of artisan fishers’ technical efficiency. Accordingly, the present study analyses Nile perch fishers technical efficiency, using a stochastic production frontier (SPF) model based on the sample of 268 Nile perch fishers in the Tanzanian portion of Lake Victoria. The translog stochastic frontier model results indicate the technical efficiency of Nile perch fishers range between 61% and 80%, with an overall average technical efficiency of 75%. This finding implies that, based on existing fishery resources, the current quantity of Nile perch catch can be improved efficiently by 25%, a reality highlighting mismanagement of the lake's fishery resources. The quantity of bait and petrol and the number of hooks used per trip are the most important fishing inputs, indicating a positive Nile perch fishing output–input elasticity. To address the Nile perch fisher inefficiency, it is important to provide subsidized inputs such as outboard engines and mesh gillnets. Provision of access to affordable credits will enable fishers to purchase less destructive fishing inputs and improve the current structure of fishery organizations.     

Distribution and Abundance of Rainbow Smelt in Western Lake Superior as Determined from Acoustic Sampling

Distribution and abundance of rainbow smelt (Osmerus mordax, Mitchill) in the western arm of Lake Superior were described through an acoustic sampling program conducted from June 1978 through early June 1980. Density and abundance were highest in shallow water (bottom depth <50 m), where rainbow smelt underwent vertical movements from the bottom and concentrated in warmer (11 to 16° C) near-surface water (2- to 30-m depth) at night. Rainbow smelt densities and abundance were extremely low in the deeper waters (>50 m) along the north shore and in the open lake. Abundance of rainbow smelt in the western area of the lake was estimated to be 286 X 10⁶ fish (4.35 X 10⁶ kg) in 1978. Abundance declined to 164 X 10⁶ fish (2.5 X 10⁶ kg) in 1979. Comparison of rainbow smelt abundance estimates with commercial yields suggested that annual fishing mortality is 15 to 27%. Predation by salmonid populations is considered a potentially important factor influencing smelt abundance levels. Rainbow smelt distribution and changes in abundance described by this study indicate smelt production is not high enough to support the fisheries or predator populations previously supported by native lake herring (Coregonus artedii, Lesueur) stocks.     

Fish catch and fishing practices in the Nam Theun 2 Reservoir and watershed (Lao PDR)

A fish catch and fishing practice monitoring survey were conducted from 2008 to 2014 in villages adjacent to the Nam Theun 2 Reservoir and its upstream tributaries. The reservoir fisheries exhibited – the three expected phases following impoundment (i.e. trophic upsurge, trophic depletion and stabilization, respectively). This study focused on assessing fish catches and fishing practices from communities living next to the reservoir, and those living upstream of the reservoir, over these phases, and to identify factors that could influence total fish catch. The fish catch appeared to be higher among communities located next to the reservoir, compared to communities living in upstream areas. Fish catches in the upstream tributaries remained relatively stable after impoundment, with a slight increase in the average catch. The reservoir exhibited a low fish yield, compared to similar reservoirs, which could be linked to its oligotrophic status. The majority of the total catch biomass of the reservoir was comprised primarily of two species (i.e. Oreochromis niloticus; Hampala macrolepidota) since a stabilization of the catches was observed. Reservoir fisheries appeared to be mainly driven by hydrological factors, specifically the influence of the rainy season peak. The results of this study indicated no over‐exploitation of fisheries occurred overall, although the fishery resource is still fragile. Fishing activities are known to occur in protected zones (productive areas with large inundated habitat areas), with higher annual total catch being observed during periods of poor enforcement of these zones. As fisheries have become an important income source for villagers living along the NT2 Reservoir, regulation and adequate management of the reservoir are recommended to maintain the reservoir fisheries as a sustainable activity.