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The use of socioeconomic and cultural parameters in the assessment and biomonitoring of ecological health of aquatic ecosystems is still in its nascent stages. Yet, degradation of aquatic ecosystems has elicited concerns because of its bearing on social and economic development of communities consisting of marginalized and vulnerable groups, as well as the expenses and technical knowhow involved in biomonitoring approaches. In this study we developed a Citizen-based Index of Ecological Integrity (CIEI) for assessing and monitoring the ecological status of vulnerable African riverine ecosystems in Lake Victoria Basin, Kenya. The hypothesis is that the citizen-led socioeconomic and cultural metrics provides a more cost-effective broad view of ecosystems than other biomonitoring methods in the assessment of water resources in the developing countries. Selected rivers in the southern part of Lake Victoria (Rivers Kuja and Sondu-Mirui) recorded the highest CIEI than their northern counterparts (Rivers Yala and Nzoia) that had moderate to poor ecosystem integrities. The study demonstrates the usefulness of this approach to elucidate the source of impairment, the extent of impacts and provide a justifiable rationale to advice policy makers on developing guidelines for conservation and management of aquatic ecosystems. We recommend for adoption and promotion of the CIEI perspective in areas where such approaches appear defensible for the assessment of catchment-wide practices in areas with robust indigenous knowledge to provide a broad-view of the ecological health of the aquatic ecosystem.

Small-scale fisheries in Kenya contribute about 4.7% of the Gross Domestic Product (GDP) in spite of high post-harvest losses. Post-harvest interventions in fisheries enable fishers and fish processors to reduce waste, maintain nutritional aspects and meet stringent demands in food quality and safety. This review highlights the benefits and pitfalls of various fish post-harvest management interventions in order to drive policy dialogue and formulation of a regulatory framework for future interventions. It relies on data obtained from the Kenya Marine and Fisheries Research Institute and the State Department of Fisheries and Blue Economy. Results depict abundant interventions in both handling and processing, but low utilization (<40% of installed cold rooms, dryers and smoking kilns) and multiplication by fishing communities. Fish products that target export markets have wellorganized structures. However, a weak regulatory framework is a key constraint in addressing post-harvest management of fish intended for the domestic market. Under-utilization of installed interventions results in continued waste of fish, contributing to food and nutritional insecurity. This review recommends the development of an effective and integrative policy framework that involves interactions across different domains, institutional mechanisms that monitor and address those interactions, analytical bases for decision making, and multi-stakeholder dialogue for post-harvest management. Such policies will enhance the adoption of post-harvest technology in small-scale fisheries in Kenya and elsewhere.

Lake Baringo is a Ramsar‐designated water body facing a myriad environmental challenges attributable to anthropogenic activities, thereby being an ecosystem under perturbation. At the same time, however, it is an important aquatic resource not only to the local community, but also to the international arena because of its rich biodiversity. It supports an artisanal fishery with four major fish of economic importance, including Oreochromis niloticus, Protopterus aethiopicus, Clarias gariepinus and Barbus intermidus australis. The once‐vibrant O. niloticus fishery that flourished before the small town of Kampi ya Samaki was transformed into a beehive of activity on the shores of the lake is no longer sustainable. O. niloticus contributed over 80% of the landed total catch up to the year 2002, averaging >600 tons annually, but had declined to about 12 tons annually by the year 2006. The introduced P. aethiopicus is currently the major fishery, representing more than 75% of the total fish landings, with the O. niloticus landing being just 1%. Although O. niloticus is listed as ‘endangered’ in the IUCN Red List of Endangered Species, it is evident that its fishery is threatened with a total collapse if sound management strategies are not implemented. Accordingly, the present study reviewed past studies on the Lake Baringo O. niloticus and critically analysed the possible reasons for its decline, as well as possible strategies directed to its recovery, conservation and management for sustainable exploitation.

Lake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attributed to overfishing, eutrophication, introduction of exotic species, pollution and possibly climate change. The lake's capture fishery, which is the main economic activity directly and indirectly supporting over 40 million people, has continued to decline after experiencing a boom between the 1970s and 1990s following the introduction of Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus). In order to augment capture fisheries from the lake, cage culture was introduced in 2005, but its sustainability and influence on the ecology of the lake are not well understood. In this review, we examine the genesis of degradation of Lake Victoria and assess the role of cage culture as both a solution to the current situation and a cause for concern for the ecology of the lake. To compile this review, we utilized data in the grey and published literature. Studies show that the degradation of the lake can be traced back to the 1930s when the trophic status and ecology of the lake started showing signs of anthropogenic influence. The Nile Perch was introduced in early 1960s to replenish the fishery but its ecological impacts were felt in 1970s and 1980s when the native haplochromine species started to disappear from catches. Progressively, the ecological changes and management concerns in the lake have become a complex mix of exotic species introductions, eutrophication, and overfishing. In this mix of persistent ecological changes, the once thriving capture fisheries revolving around the two exotic species (L. niloticus and O. niloticus) have significantly declined threatening the livelihoods of millions of people directly and indirectly involved in the fisheries. These declines necessitated the introduction of cage culture in 2005 to fill the increasing demand for fish from the lake. Ever since, cage numbers have increased tremendously (&gt;6 000 by 2020) and is now operated by over 60 different firms which are owned either individually or by groups. Over 70% of the cages have been installed in shallow areas within the Winam Gulf which goes against the guidelines on cage installation and operation; regulations on cage farming were introduced after the activity had gained momentum in the lake. Limnological data in areas of the lake that have been stocked with cages has shown evidence of negative effects on water quality. This decline in water quality can be attributed to remnant feeds used in cages, of which 50% are the sinking types, and wastes from fish excretion and egestion. Although data are limited, the potential influence of cage farming on the already altered ecology and environment of Lake Victoria needs to be recognized and investigated. This study recommends studies targeting operations of cages in the lake, including a comprehensive environmental audit to inform their sustainability and relevant policy.

This study investigated the effects of manipulating carbonnitrogen (C/N) ratio and fish stocking density on pond productivity: total heterotrophic bacteria counts, plankton biovolume and benthic macro-invertebrates. Labeo victorianus juveniles were reared for 72 days in 18 hapas suspended in six ponds measuring 150 m 2 at densities of 10, 15 and 25 fish m À2 . Fish in hapas received a locally formulated and prepared feed containing 295 g kg À1 crude protein, and ponds were treated with a C/N ratio of either 10 or 20. All treatments were carried out in triplicate. Increasing C/N ratio from 10 to 20 increased phytoplankton by 13% and zooplankton biovolume by 25% in the water column (P < 0.001). Total benthic macro-invertebrates biovolumes were also 30% higher (P < 0.05) with a C/N ratio of 20 compared to 10. Total heterotrophic bacteria counts increased both in water and sediment by 29% while net yield increased by 15% from 1534 (C/ N 10) to 1821 (C/N 20) kg ha À1 72 day À1 . C/N ratio of 20 and a stocking density of 25 fish m À2 led to the highest yield, survival, production and net benefits. It is suggested that polyculture may lead to better utilization of pond communities to further improve pond productivity.

The study was conducted in Lake Baringo, Kenya, and determined quantitative relationships between water‐level changes, water quality, and fishery production for purposes of evidence‐based lake basin management. Long‐term data on water level (1956–2020), water quality (2008–2021), and fisheries yields (1982–2021) from Lake Baringo were analysed using a combination of statistical methods. Linear and waveform regression analyses were used to describe patterns of lake‐level fluctuations over time, while Pearson's correlation was applied to determine the concordance of lake level changes with water quality parameters, landings, and condition of fish species. Principal components analysis (PCA) results grouped the study period into different years based on annual water quality variable levels. Locally weighted scatter plot smoothing (LOWESS) analysis showed the annual lake level amplitude declined over time with peak values in 1964 (8.6 m) and 2008 (9.4 m). The waveform regression significantly modelled lake‐level fluctuations as indexed by annual deviations from the long‐term average (DLTM) and showed a 20‐year oscillation between peak water levels in the lake. There were significant positive correlations of water‐level fluctuations (WLFs) with water quality variables and water quality index (WQI) in Lake Baringo. Linear regression analyses showed a significant concordance (p < 0.05) between the annual fishery yields and the rising WLFs (r = 0.66). Also, there was a significant (p < 0.001) relationship between the condition factor of the native species, Oreochromis niloticus, and the annual lake level amplitude (r = 0.69), while catches of the lungfish, Protopterus aethiopicus, and Labeobarbus intermedius showed a differing relationship with WLFs in the lake indicating a species‐specific influence of WLFs on catches. Overall, the results demonstrate that WLFs of Lake Baringo are a significant driver of fish species biomass, species condition, and physico‐chemical properties of the lake.

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