Lake Kariba, created in 1958, experienced changes, notably the decline of the Limnothrissa miodon fishery, which have been attributed to climatic change. Air temperatures rose abruptly by 1.1°C between 1980 and 1981, but the temperature of the lake did not follow this pattern. Temperatures at 10 m depth increased by 8% between 1961 and 1971, remained stable until 1984, then declined and by 1992 the temperature was about 7% lower than in 1961. The causes of this are unclear but it followed the hot and dry El Niño droughts of 1982-83 and 1991-92. The lake warmed again by 2007-2011 with temperatures at 10 m being about 10% higher than in 1961, while at 40 m it was 16% higher indicating a faster warming rate in deeper waters. The thermocline fell from 15-20 m in 1968 and 1986 to 20-25 m in 2011 and the temperature gradient decreased by > 50%. The epilimnion became more homogenous, with no evidence of anoxia in the upper 20 m in 2007-08, and the normal monomictic thermal regime may change, thus affecting nutrient circulation and the seasonal abundance of plankton. Both zooplankton and phytoplankton communities have evolved since the lake was created, but these changes occurred before any evidence of warming. The fishery has been declining since 1996 but there is no evidence that climate change is responsible; the number of fishing vessels is presently about three times the recommended level and fishing effort is almost certainly the main cause of the problems. All African lakes support fisheries and it is essential to consider fishing, which changes fish species composition, demographics and abundance, characters that could also be affected by climate change.

We present the Multi-metric Index of Biotic Integrity methodological approach that allows for the ranking of major river catchments based on pollution status in the Kenyan portion of Lake Victoria, Africa. The study has a broader applicability to all of Lake Victoria, other African Great Lakes, and all lakes that have riverine discharge. The method presented utilizes water quality and environmental data, local knowledge, and pre-existing literature. The parameters considered were sampled from 2016 to 2018 during the dry season (July sampling) and the wet season (March sampling). Separation power of Mann-Whitney U test (p < 0.05) qualified 11 discriminant metrics for both macroinvertebrate and fish samples into the scoring system of 1, 3 and 5 in the formulation of final Multi-metric Index of Biotic Integrity methodological approach. Rivers in the northern section had lower Multi-metric Index of Biotic Integrity methodological approach scores, as compared to southern counterparts. The Multi-metric Index of Biotic Integrity methodological approach ranking herein was validated by community perceptions on pollution levels. River Nzoia catchment emerged as the most polluted, followed by River Yala, River Kuja, and Sondu-Miriu. Siltation, domestic washing, litter and refuse emerged as the main agents of pollution. Management authorities ought to reinforce a balanced utilization of the vital water resources to minimize future impacts, and promote catchment wide practices that ensure ecological health sustainability of the lake ecosystem.

Lakes, rivers and oceans provide unique resources and support fisheries and aquaculture worldwide. The fisheries and aquaculture sector of Kenya contributes approximately 0.8% to the country's GDP. Marine production is about 9 000 tonnes per year. Marine finfish form the bulk of the marine production, while shellfish (e.g. prawns, lobsters and crabs), molluscs (e.g. octopi and squids) are underexploited. The Fishery sector has the potential of about USD 5 billion for the Blue Economy in Kenya. Crab fishery in Kenya is active in some areas of the south and north coast. The crab resources along the Kenyan waters are diverse and a variety of species are edible. The most commonly fished crab by artisanal fishers is the Mangrove Mud Crab Scylla serrata. Semi-commercial and industrial fishers usually have portunid and other deep sea crabs as by-catch in trawl and longline fisheries, which in many cases are unutilized. Exports of live crabs have increased over the years, with exports mainly to Asian countries. Export of frozen crabs started recently. The need to sustainably utilize lake, river and ocean resources is recognized and important in promoting Blue Economy. Sustainable development of crab fishery provides a potential area for the Blue Economy development in Kenya. Research is essential to crab fishery development.

Mud Crab fattening is a relatively new business idea in Kenya and is highly lucrative due to the reasonable prices offered at tourist hotels. This study was aimed at developing appropriate culture techniques for Mud Crabs to maximize harvestable biomass by the local communities and avoid recruitment overfishing. Growth and survival rates for mixed sex Mud Crabs was investigated for a period of 230 days in Mida Creek, Kenya, using bottom and floating cages, and two feed types in a crab fattening experiment. Crabs attained harvestable weight by the third month for both floating (466.2 ± 137 g) and bottom cages (542.2 ± 109.3 g). There was no significant difference in mean total weight of mixed-sex crabs in the two culture systems (t = 1.75, p>0.05), however males showed significantly higher total weight gain compared to females. A higher overall survival rate was found for crabs cultured in floating cages (63.8%), compared to bottom cages (44.9%). There was no significant difference in growth performance between crabs fed gastropod tissues and those fed fish offal. The long-term specific growth rate for floating cages (0.69 g d^-1) was not significantly different from that of bottom cages (0.92 g d^-1). An analysis of potential return on investment showed the floating cages to be more profitable per production cycle compared to the bottom ones. The floating cage system and mono-sex male crab culture are recommended to farmers within mangrove tidal flats in Kenya.

Biodiversity assessments within seagrass beds were conducted in six sites in Lamu, Kenya; namely, Kiweni, Tauzi, Wange, Ntopate, Manda toto and Ngoi. The objective of the assessment was to collect baseline information of the seagrasses of Lamu County in Kenya. Our findings revealed that nine out of the twelve seagrass species found in Kenya were found in the study sites. The dominant seagrass species Thalassodendron ciliatum was found to occur in deeper subtidal areas, while the pioneering species occurred in intertidal shallower areas. Average shoot densities per site ranged from 2.4 ± 1.7 shoots m^-2 of Cymodocea serrulata to 1025.9 ± 139.3 shoots m^-2 of Syringodium isoetifolium in Ngoi. Canopy heights ranged from 0.1 ± 0.1 cm of Halodule ovalis in Tauzi to 16.3±1.3.5 cm of Syringodium isoetifolium in Ngoi. Although the seagrass species characteristics were much lower than that found in similar mangrove fringed seagrass beds of Gazi Bay, the majority of the fish found in these seagrass areas were invertivores which indicates that these seagrass sites form a refugia for adult fish populations with nursery grounds being located elsewhere.

This study forms the first comprehensive assessment of the seagrasses of Lamu and it provides important baseline information on seagrass beds. Such biodiversity information provides important support for decision-making for coastal areas that are targeted for infrastructural development such as Lamu. Biodiversity information of such critical habitats form a critical data base for marine spatial planning and can be used to effectively guide the integration of biodiversity and coastal livelihoods in the sustainable development of Kenya's coastal areas.

Cage aquaculture has been on a steady rise in Lake Victoria, Kenya, since 2016, resulting in the current culturing of over 3,600 cages of Tilapia (O. niloticus) (Orina et al., 2018). Unfortunately, there has been limited, if any, focus on fish health aspects. Rise in intensification and commercialization predisposes fish stocks to disease due to rise in stress levels and consequent reduction in the fish immunity. Nutrient rich surroundings create a conducive environment for rapid proliferation of bacterial and saprophytic fungal growth leading to net clogging and consequently a low biological oxygen demand. Such conditions predispose the stocks to infections. This study was conducted to provide a baseline analysis of the health conditions/status of the cultured fish in this region. It encompassed studies from 2016 to 2018 on tilapia of the genus O. niloticus using both experimental (using standard procedures and protocols) and socio-economic studies (using structured questionnaires, see annexure 1). Results found the following occurrences; bacterial infections (10%), fungal infestations (12.5%), myxosporean parasites in the gills (5%), parasitic copepods (10%) and fin rot (2.5%) in the stocks. There were no significant differences between abiotic parameters in the cage locations and the wild (p > 0.05). Additionally, 90% of the respondents had no fish disease training or clue on the treatment action necessary whenever fish diseases struck. Findings from this study put to the fore the significance of fish diseases in a cage culture system in light of commercialization of the industry and the importance of biosecurity and maintenance of optimal environmental conditions within the scope of Blue Economy growth in this region. This study did not detect any disease or parasite of zoonotic importance.

Capture fisheries and aquaculture have remained important sources of food, nutrition, income and livelihoods to millions globally, with annual per capita consumption of fish in developing countries having increased from 5.2 kg in 1961 to 18.8 kg in 2013. On the contrary, low income food-deficit countries annual fish per capita consumption rose from 3.5 to 7.6 kg against 26.8 kg among industrialized countries. Increased demand for animal protein and declining capture fisheries has seen aquaculture grow rapidly than any other food production sector over the past three decades. Rapid global aquaculture growth is directly related to levels of technological advancement, adoption and adaption prompting aquaculture transition from semi-intensive to intensive and super intensive production systems among developing and developed countries. In light of the aquatic environment economic potential, cage culture in Lake Victoria is fast gaining prominence in aquaculture production contribution. This began with trials by Kenya Marine and Fisheries Research Institute and Uganda's National Fisheries Resource Research Institute and later by private investors at Dunga and Obenge beaches of Kenya, Source of the Nile in Uganda and Bulamba Beach Management Units in Bunda District of Tanzania. However, only Kenya has so far documented cage culture development recording 3,696 cages across the five riparian counties with an estimated production capacity of 3,180 MT valued at Kshs 955.4 Million (9.6 million USD), created over 500 jobs directly and indirectly created income opportunities for over 4,000 people. The sub-sector's value chain, its supportive value chains and associated enterprises are rapidly expanding thus creating jobs, enhancing incomes and ensuring food security in rural and urban areas. As cage culture commercialization takes root, there is urgent need to address issues such as introduction of alien species, diseases, marine parks and maximum carrying capacity among other aspects. This will require trans-boundary policy to ensure sustainable utilization of the lake as a common resource.

With the global decline in capture fisheries, aquaculture remains alternative in bridging the gap and meeting the demand for fisheries products. Currently, aquaculture contributes approximately 50% of world total fishery production, hence becoming an important intervention in promoting food and nutritional security, and employment creation. Western Kenya is suitable for aquaculture production due to favorable climate and good soil as well as high demand for fish. The present survey purposed to assess the Socio-demographic characteristics of fish farmers, fish feed and seed producers in 9 Counties within Western Kenya. The information obtained included socio economic dynamics and challenges to fish farming. Fish farming mainly occur in rural areas in Western Kenya where the most dominant system is earthen ponds, measuring 300 m². Aquaculture in the region is male dominated and majority of players practice individual enterprises. The majority of the hatcheries are authenticated and the lack of credit facility was mentioned as the most important challenge. However, for feed producers lack of adequate raw materials was the most important bottle neck. From this study, both environmental and social factors in the region must be synergized to achieve aquaculture sustainability. There is need for empowerment of farmers through capacity building and availability of credit facilities whereas hatcheries and feed producers must be empowered with adequate skills and infrastructure in order to adhere to good standards.

For many years, aquaculture has been erroneously viewed as a male-dominated sector, offering women inadequate opportunities partly due to the high capital investment requirement and or the technologies linked to the venture. Women work in all areas of the aquaculture value chain but their opportunities have not kept pace with aquaculture growth. Hence, they form a larger component of the poor, limiting their income-generating activities and asset building potential. Gender disaggregated statistics that could track women's engagement in aquaculture activities in Kenya are scanty. Hence, women's presence, influence and interests are invisible. All aquaculture labour practices should embrace the Sustainable Development Goals 5 that focus on gender equality and empowerment of all women and girls. To that end, gender equality must be mainstreamed into aquaculture planning, development, monitoring and evaluation. This will require concerted political efforts by sector leaders, advocates and gender champions, supported by new technical instruments for implementation. The study leverages on incorporating gender lens and making gender visible in every phenomenon, questioning if, how and why processes, opportunities and standards differ systematically for women and men and not solely for women. Finally, it proposes sections where women's engagements can be strengthened to increase the importance of aquaculture production in Kenya.

Feeds and feed management practices are key to the development of the aquaculture sector. To achieve high levels of aquaculture production, fish farmers need nutritionally adequate and cost-effective feeds, which are coupled with good feed management practices. Access to high quality and cost-effective feeds is one of the prerequisites to successful fish farming. This paper reviews the current status of the Kenyan fish feed industry and feed management practices. The review includes constraints and opportunities in fish feeds from a farmer's perspective. The review shows that the fish feed industry has been boosted by the development of fish feed standards, which has ensured access to high-quality fish feeds by all farmers. Feed management practices considerably impact on the economic performance in fish production. Thus, adopting appropriate feed management technologies and feeding strategies is instrumental in maximizing aquaculture productivity. Some of the major challenges faced by fish farmers in the feed sector including limited access to finance, lack of appropriate technical innovations, limited knowledge in feed formulation and processing and poor feed handling and storage are discussed. These challenges pose limitation in investment opportunities for a viable and sustainable fish feed processing and manufacturing to meet the rising demand occasioned by increased demand for fish food in Kenya. There is a huge potential to develop public-private partnerships with farmer groups to improve access to training and information dissemination on feeds availability and quality. Training fish farmers on feed formulation using locally available feed ingredients provide an opportunity to reduce feed costs, increase feeding efficiency and improve profitability. This paper reviews the current status of the Kenyan fish feed industry and feed management practices including constraints and opportunities from a farmer's perspective.

The importance of situation analysis in the project cycle cannot be overstated. This research was carried out in twelve sites where mariculture was practiced in Kilifi, Mombasa and Kwale Counties in the coast of Kenya. The general objective of the research was to assess the effects of situation analysis practices on implementation of mariculture projects in Kenya. The specific objectives were to:- examine the effect of stakeholder analysis on implementation of poverty alleviation mariculture projects, establish the effect of problem analysis on implementation of mariculture projects, and determine the effect of needs assessment on implementation of poverty alleviation mariculture projects. The research was based on quantitative research approach with a cross sectional survey design. Simple random sampling was used to select the number of subjects that represent the target population in the survey. Guided questionnaire administration was adopted to capture responses from members of organized mariculture groups. Factor analysis and regression analysis were conducted on the data collected from the questionnaire survey. Results showed that the poverty alleviation mariculture projects in Kenya are dominated by female actors compared to male actors. Factor analysis revealed that degree of success and degree to which the mariculture projects have addressed their objective of poverty alleviation were the most important measures of project implementation and were named effectiveness. Regression analysis showed that there was a significant positive relationship between stakeholder analysis and effectiveness (β = 0.726; t = 12.59; p = 0.000). Being the single most significant factor influencing mariculture project implementation, stakeholder analysis should be undertaken at the situation analysis stage so that it informs project design. It was concluded that improvements in situation analysis practices brought about by improvements in stakeholder analysis would address poverty among coastal fisher communities by improving implementation of poverty alleviation mariculture projects.

The economic potential of Kenya marine resources is critical for the socioeconomic development. The current study reports fisheries output from marine systems in Kenya as a priority for Blue Economy investment in order to rival the current production from inland systems as a trigger for sustainable development. The assessment of fish landings and economic value was based on Catch Assessment Surveys, cruises and secondary literature. Kenya's inland capture fisheries contributes about 83%, aquaculture 12%, and marine artisanal fisheries 5%. Lake Victoria that contributes up to 90% of inland capture fish production has shown decline in catches in the recent past and the trend indicates that the fishery may not be sustainable. The Kenya Exclusive Economic Zone has a coast line of about 647 km and an area of 142,000 km² that constitutes about 42% of the country's surface area and has several commercially important species that are barely exploited; yet it produces a paltry 26,000 mt annually that is estimated at an export value of about USD 50 million. However, recent estimates have found that Kenya Exclusive Economic Zone could contain up to 2 million mt of fish that is valued at about USD 130 million. Furthermore, additional worth along the value chain and with substantial trickle-down effect that could have a positive impact on the Blue Growth in Kenya and other developing nations with oceanic potential – triggering the possibility for sustainable exploitation.