Nicholas Otieno Outa

Maseno University · Department of Fisheries and Natural Resources

For many Kenyans, the aquaculture business provides a vital source of food and work. However, information on Kenya’s aquaculture sector’s resilience in the face of emerging global shocks such as the COVID-19 pandemic requires additional examination. Prior to the epidemic, Kenya’s aquaculture industry had grown from a tiny participant to a critical...

The capture fisheries production sector, which is the main source of consumed fish in Kenya has been declining over the years, causing a huge deficit in fish supply in the local market. Even though aquaculture has been fronted as a stop-gap measure, there are still eminent fish supply gaps, prompting the importation of frozen tilapia, mainly from C...

This study examines the impacts of the Covid-19 pandemic and adaptive strategies to build resilience among stakeholders and actors in the aquaculture value chain in Kenya. Prior to the pandemic, Kenya's aquaculture sector had progressed from a minor player to a key component of the country's fish food system. Fish and fishery products have become t...

In Kenya, breeding programmes whose source of genetic material is local water bodies are at inception with the National Aquaculture Research Center, Sagana being the Nile tilapia and African catfish breeding nucleus. Fish are susceptible to a variety of infections and diseases. These microorganisms are often present on the external surfaces and vis...

Nile tilapia (Oreochromis niloticus) is one of the most farmed fish globally, with a significant contribution improving local livelihoods, especially in developing countries. Nile tilapia was first cultured in Kenya in 1924 and is the most cultured fish species. Annually , O. niloticus accounts for 62% (∼15,000 tonnes) of total aquaculture producti...

The dwindling capture fisheries has triggered an increase in Kenya's annual fish demand deficit, currently estimated at 553,000 MT. With the adoption of sustainable policies, aquaculture can bridge and surpass this deficit. Kenya's fish farming environment is however characterized by its highly fragmented production farms, which limit the dynamism...

Rastrineobola argentea (omena) is the second most important species in the fisheries of Lake Victoria after Nile perch. However, its fisheries have negative impacts on the ecology of the lake especially because of the high numbers and diversity of bycatch resulting from the fishery. This study conducted a rapid assessment in Dunga beach in Kisumu,...

As researchers, we use academic writing to present our results to other academics and to a wider audience. In doing so, we may be tempted to use persuasive communication devices for promoting our research. These devices may be at risk of misleading readers and reviewers when assessing our research. In this document, we identify a list of such commu...

Lake Victoria, like many other lakes in Africa, is affected by water hyacinth that reside in several bays for the majority of the year. The weed affects several economic activities of the local communities and denies revenue to the government from blue economic activities related to the lake. The present study examined the interaction of water hyac...

Water quality and the environment greatly influence the existence and proliferation of parasites in the water and consequently, fish. This can have profound implications on aquaculture within the water bodies. Few studies have been conducted on parasite aggregations about the water quality in small water bodies in Kenya. This study assessed the sui...

As capture fishery sector continues to decline, aquaculture industry must be accelerated to bridge the fish supply gap especially in the developing countries. However, in most developing countries, aquaculture sector is characterized by low productivity due to inefficient technologies, hence the need for innovative aqua-technologies that can stimul...

The amount of frozen tilapia import from China has increased over the past five years to the current 20,000 tons per year. The imports have assisted in bridging the fish production deficit in the country. This study was conducted to determine the socio-economic effects of imported tilapia on the local fish market and value chain in Kisumu County. P...

The decline in capture fisheries of the world has necessitated the production of fish under different aquaculture systems to bridge the gap in demand. Aquaculture contributes about 50% of fish consumed worldwide. Today, the total annual fish production in Kenya is estimated at about 150,000 metric tons, against an annual demand of 500,000. With the...

The study was conducted at Kenya Marine Fisheries Research Institute (KMFRI), Sangoro Station, Kenya to compare the growth perfomance of Oreochromis niloticusfry under different protein levels in a biofloc system using weight-length regression models and Fulton`s condition factor (K). Fry of initial mean weight 0.07 ± 0.03 g and length 1.30 ± 0.2...

Coptodon zilli and Micropterus salmoides were introduced into Lake Naivasha in 1929 and 1959, to boost the fisheries and for recreational fishing respectively. The population of the two fish species in the lake has been declining making it necessary to assess selected growth aspects to inform management and policy making for recovery and establishm...

The Nile tilapia (Oreochromis niloticus) was introduced into Lake Naivasha to provide exploitable fisheries, being one of the commercially important fish providing livelihoods to communities around the lake. Its stocks in the lake have been declining, however, because of intense fishing, ecological changes and effects of other exotic species. The...

The Nile tilapia, Oreochromis niloticus was introduced in Lake Naivasha to provide exploitable fisheries. It is one of the commercially important fish providing livelihoods to communities around the lake. However, its stocks in the lake have been declining due to intense fishing, ecological changes and effects of other exotic species. This study in...

Lake Victoria, the second largest freshwater lake in the world, supports an enormous flora and fauna biomass, with a large human population around the Lake. The lake is a source of food (fish), water for domestic use and crop and livestock production, transportation and tourism, among other uses. As a result of these varied uses, human intervention...

Fish stocks over exploitation and excessive water abstraction in Lake Naivasha have caused drastic changes in the lake’s ecosystem and fisheries. As a result of this, measures were taken by concerned stakeholders to protect and safe guard the fragile lake ecosystem. A study was conducted on the lake’s fishery to identify fish critical habitats and...

Lake Victoria just like many other lakes is affected by water hyacinth which resides in several bays for the better part of the year. This weed affects several economic activities of the locals and denies the government revenue every year from blue economic activities related to the lake. This paper explores the interaction of water hyacinth with b...

Fish and other aquatic organisms have been introduced into new environments for various reasons. Provision of sports fishery, supplemental to stocks, to fill empty niches, control weeds, and disease vectors and even create a commercial fishery are some of the reasons why fish species are introduced into new ecosystems. Lake Victoria and Lake Naivas...

Lake Victoria which is the second largest freshwater lake in the world supports a large population living around it through provision of food; fish and employment; both directly and indirectly. Due to its varied uses, human intervention within the lake and its catchment has caused several ecological changes in the recent years which have had profou...

Lake Victoria, the second largest freshwater lake in the world supports a huge flora and fauna with a large human population around the Lake. The Lake is a source of food (fish), water for domestic use and crop and livestock production, transportation, tourism among others. Due to its varied uses, human intervention within the lake and its catchmen...

Nile tilapia Oreochromis niloticus is now the most abundant and commercially important tilapiine in Lake Victoria. From the total of 1 512 fish sampled from commercial gill net fisheries during 2014 and 2015, 809 (54%) were males and 672 (44%) were females, giving an overall sex ratio of 1.20 males: 1.00 females. The mean (± SE) length and weight f...

This study investigated the growth, mortality and recruitment of Lates niloticus in Lake Victoria basis on length–frequency data collected during the period 2014-2015. The asymptotic length (L∞) had a value of 124 cm TL, growth curvature (K) of 0.22 year⁻¹, total mortality (Z) of 0.96 year⁻¹, a natural mortality (M) of 0.42 year⁻¹, a fishing mortal...

Samples (6404) of Nile perch were collected monthly from commercial catches between June 2014 and June 2015. The total length (cm), weight (g) and sex of fish were all determined in the field, with 3771 (59%) being male and 2059 (32%) being female fish, for an overall sex ratio of 1.83:1.00 (male: female). The average length and weight for all fish...

This study compared water quality parameters, fish species diversity and abundance in the water hyacinth infested and non-infested areas. The mean (±SD) water temperature of the infested and non-infested areas were 25.60±4.39 0 C and 24.62±4.94 0 C respectively. Dissolved oxygen 2.44±1.14 mgl-1 of the infested area was significantly lower than non-...

The study was conducted between January and March 2015 in the Kenyan waters of Lake Victoria. Duplicate composite vertical samples of zooplankton were collected from the water column using 50μm plankton net of 30 cm diameter and preserved with 5% formalin prior to identification in the laboratory. Water quality parameters were also measured in-situ...

A total of 289 fish were analysed in this study, with Caradina nilotica (44%) being the dominant food item in their diet, while tilapia (8%) contributed the least. Haplochromines, unidentified fish prey and juvenile Nile perch also were observed. An ontogenic shift was observed, with C. nilotica contributing highest (61.1%) of the diet of fingerlin...

The Nile tilapia (Oreochromis niloticus) was introduced into Lake Victoria in the early 1950s and 1960s and has since become the dominant tilapiine in the lake. This study investigated the growth and population parameters of O. niloticus in Lake Victoria on the basis of length–frequency data collected during the period June 2014 and June 2015. The...

The present study investigated on Length-weight relationship, Condition factor, Sex ratio, Gonadal Somatic Index (GSI) and Size at Maturity of Omena Rastrineobola argentea. Samples (2240 fish) were collected monthly between August 2014 and March 2015 in the Kenyan waters of Lake Victoria. Results for length-weight relationship revealed that R. arge...

African carp, Labeo victorianus, is one of the threatened endemic fishes of Lake Victoria which requires conservation and has potential for aquaculture. We conducted a series of experiments on L. victorianus aiming at producing juveniles for both human consumption and stock enhancement. A total of 79 broodstock (mean body weight = 227.06 g) were co...

Studies on the diet of Rastrineobola argentea were conducted between August 2014 and March 2015 in the Kenyan waters of Lake Victoria. Stomach contents of 1154 specimens collected from commercial fishers and experimental seining were analyzed. Juveniles of R. argentea under 30 mm SL fed almost exclusively on zooplanktons, while adult fish larger th...

Cyperus papyrus (L.) growth rate and mortality is influenced by environmental conditions prevailing in the wetland. To assess growth dynamics of C. papyrus in relation to water depth and anthropogenic (exploitation) pressures, monthly and bi-monthly measurement of culm length and girth were done between June and December 2010 (period 1) and April t...

This study aimed at determining the length-weight relationship (LWR), condition factor (K) and length at first maturity of common carp (Cyprinus carpio) in Lake Naivasha, Kenya. The fish were sampled monthly using a gill net of mesh size between 1.5 to 5 inches. The lake was accessed using an engine boat from November 2013 to February 2014. A total...

A study was done on feeding ecology of re-introduced Oreochromis niloticus (L.) in Lake Naivasha, Kenya between November 2013 and February 2014. The main focus of the study was on fish size, diet, habitat, and diel feeding regime. 434 fish samples were collected every two weeks from five stations covering the entire lake by use of gill nets (50 mm...

Fish samples (541) were collected every two weeks from different parts of Lake Naivasha using gill nets (50 mm to 150 mm mesh size) and beach seines (< 10 mm) between November 2013 and February 2014.The main focus of the study was on sex ratio, length-weight relationship and body condition of Nile tilapia. Results revealed that there were more male...