Feeding selectivity of wild and pond-cultured Nile tilapia<i>Oreochromis niloticus</i>in the Lake Victoria basin in Mara, Tanzania

Rumisha, Cyrus; Nehemia, Alex

doi:10.2989/16085914.2013.784698

Cited by 8 publications

(9 citation statements)

References 11 publications

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“…Using stable isotope analysis, Briones et al (2016) showed that O. niloticus from Lake Sampaloc (one of the SMLs) relies strongly on periphyton compared to other fish species. It has also been reported that diatoms and dinoflagellates are the main components of diet for O. niloticus (Rumisha and Nehemia, 2013), further supporting our analytical result.…”

Section: Discussionsupporting

confidence: 91%

“…In contrast, O. niloticus is well known to have a wider range of food items, such as phytoplankton, zooplankton, insects, and fish larva. It has also been reported to undergo temporal shifts in food habits in accordance to its ontogeny and food availability (Zenebe et al, 1998;Nijiru et al, 2004;Rumisha and Nehemia, 2013;Mendoza et al, 2015). Such omnivory and food habit flexibility may be a cause of the dissociation with specific basal food sources.…”

Section: Discussionmentioning

confidence: 99%

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Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers

et al. 2022

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Food web studies rely heavily on the use of traditional gut content analysis or the fairly popular stable isotope analysis rather than fatty acid analysis (FAA) despite its straightforward process, and ability to identify and characterize more diverse trophic pathways. In this study, we employed fatty acid (FA) biomarkers as a preliminary attempt to trace and characterize trophic pathways in food webs of four tropical lakes of volcanic origin in Luzon Island, Philippines - three clustered maar lakes (Yambo, Pandin and Calibato) and a large caldera lake (Taal). These lakes have a long history of human disturbance but limited ecological data. Knowledge of basal food sources and existing trophic dynamics of organisms are generally non-existent. Particulate organic matter (POM), zooplankton, and fish species were collected in August 2019 from the study lakes as representative of three trophic guilds. Non-metric multidimensional scaling (NMDS) and principal component analysis (PCA) were conducted to analyse FA profiles and characterize trophic relationships between representative organisms. For the POM, within lakes comparison of taxon-specific FA profiles showed a significant difference between the surface and near bottom depths, with the former dominated by photoautorophs and the latter by chemotrophs, suggesting the ability of FAA to effectively delineate between micro-organisms. Between lakes comparison also showed significant difference between the caldera and maar lakes, with the latter containing higher composition of bacterial FA, reminiscent of the considerably smaller lakes’ response to the impact of unmitigated organic loadings from anthropogenic activities. Taken together with the primary consumers’ FA profiles, analysis confirmed the ability of FAA to discriminate between FA profile sources. PCA explained >70% of the variance in the FA compositions for three trophic guilds in the two deepest lakes, which delineated both zooplankton and fish species food selectivity in each lake, alluding to FAA’s capacity to characterize dietary reliance of various species in an environment with numerous food sources. Although certain limitations were encountered, such as the specificity of the sampling depths for POM, and the small sample size of the representative species of the third trophic level, this study demonstrated the effectiveness of FAA as a powerful ecological tool for disentangling intricate lake food webs comprising various food sources. Overall, this study provided baseline information on basal food sources and trophic pathways of representative organisms from four tropical lakes. Taken together, FAA studies have wide application in understanding food webs, including anthropogenically-threatened lake ecosystems.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers

et al. 2022

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“…O. niloticus is an omnivorous fish consuming diverse species of phytoplankton, insects, and juveniles fish. A study by Rumisha and Nehemia [ 37 ] reported that O. niloticus feeds primarily on Cyanophyta, diatoms, dinoflagellates, desmids, and green algae. It has also been found to expand its diet from plant materials to include insects and fish [ 38 ].…”

Section: Discussionmentioning

confidence: 99%

Fatty Acid Composition and Levels of Selected Polyunsaturated Fatty Acids in Four Commercial Important Freshwater Fish Species from Lake Victoria, Tanzania

Robert¹,

Mfilinge

Limbu

et al. 2014

Journal of Lipids

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Fatty acids (FAs) particularly ω3 and ω6 polyunsaturated fatty acids (PUFAs) play important role in human health. This study aimed to investigate the composition and levels of selected ω3 PUFAs in four commercial fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), Tilapia zillii, and dagaa (Rastrineobola argentea) from Mwanza Gulf in Lake Victoria. The results indicated that 36 types of FAs with different saturation levels were detected. These FAs were dominated by docosahexaenoic (DHA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and eicosatetraenoic acids. O. niloticus had the highest composition of FAs (34) compared to L. niloticus (27), T. zillii (26), and R. argentea (21). The levels of EPA differed significantly among the four commercial fish species (F = 6.19, P = 0.001). The highest EPA levels were found in R. argentea followed by L. niloticus and O. niloticus and the lowest in T. zillii. The DPA levels showed no significant difference among the four fish species studied (F = 0.652, P = 0.583). The study concluded that all four commercial species collected from Mwanza Gulf are good for human health, but R. argentea is the best for consumption because it contains higher levels of ω3 FAs, mainly EPA.

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“…Several studies (Ndlela et al., 2016; Sinha et al., 2012; Paerl and Paul, 2012) reported species of M icrocystis , Anabaena , Cylindrospermopsis raciborskii and Plantolyngbya (Sekadende et al., 2005; Miles et al., 2013) in Lake Victoria. Another study, for example, Rumisha and Nehemia (2013) on feeding selectivity of wild and cultured Oreochromis niloticus (Nile tilapia) registered high concentration of Microcystis , A nabaena flos-aquae , and Lingbya circumcreta species in Lake water than in fish ponds. Changes in water quality in Lake Victoria is attributed to anthropogenic activities (Silsbe et al., 2006).…”

Section: Main Textmentioning

confidence: 99%

The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania

Kimambo

Gumbo

Chikoore

2019

Heliyon

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Cyanobacteria (blue-green algae) are photosynthetic bacteria that under favorable environmental conditions produce secondary metabolites (cyanotoxins) which are harmful to the environment, including humans. The mass proliferation of harmful cyanobacteria is termed CyanoHABs. CyanoHABs can adapt to different climatic fluctuations, therefore, understanding their dynamics in freshwater systems is crucial. Variation in climatic and hydrological processes, changing land use and economic growth all influence the occurrence and distribution of CyanoHABs. There have been inadequate CyanoHAB studies at local scales, therefore their occurrence and dynamics cannot be generalized. This study reviews and synthesizes cases of CysnoHAB occurrence, magnitude, and timing and how these are linked with climatic and hydrological variations in the United Republic of Tanzania. In this study, a scoping review approach was adopted. Research articles, reports, and databases were consulted. The most common species of toxin-producing cyanobacteria were identified in different water bodies in Tanzania, as well as the record of mass fatality of birds (Lesser Flamingo) in Lake Manyara, which in almost all cases occurred during dry years. While previous studies on CyanoHAB dynamics and their links to climate, hydrological, and environmental changes have not been undertaken in Tanzania, there are studies in Lake Victoria and Tanganyika. Therefore, there should be an immediate response from water users, managers, researchers, and water authorities to address and actively engage in monitoring and managing the risks associated with CyanoHABs in Tanzania.

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Feeding selectivity of wild and pond-cultured Nile tilapiaOreochromis niloticusin the Lake Victoria basin in Mara, Tanzania

Cited by 8 publications

References 11 publications

Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers

Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers

Fatty Acid Composition and Levels of Selected Polyunsaturated Fatty Acids in Four Commercial Important Freshwater Fish Species from Lake Victoria, Tanzania

The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania

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