Mr. Fredrick Guya

Email: fguya@kmfri.go.ke

Fredrick Jared Guya is a Senior Research Scientist at the Kenya Marine and Fisheries Research Institute (KMFRI), holding an M.Sc. in Marine Geochemistry from the University of Victoria, Canada. He has practised under this profession for over 30 years while working with KMFRI, a body mandated to undertake researches on the health and ecology of aquatic ecosystems.

Global aquatic ecology have historically been transformed from desirable to less desirable through both natural and anthropogenic forcing. The ensuing transformations have directly or indirectly triggered mass biotic migrations, loss in biodiversity and abundance with occasional extinctions, changes in pelagic food web dynamics and nutrient cycling. The historical relationships between environmental and observed biotic changes have been difficult to establish due to paucity of data. His studies are therefore interested in understanding both neo- and paleo-limnological shifts, sources/causes, and associated ecological impacts, with a view to providing management solutions that may lead to aquatic health restorations and consequential disaster preparedness.

Remarkable findings and management actions have emanated from the novel studies undertaken so far:

• Mapping of the pollution spectrum of rivers that drain into Lake Victoria – Kenya, identified River Nyando as the most polluted with the findings published in Guya, F. J. (2019).
• The survey of both natural and anthropogenic sources of pollution into Nyanza Gulf of Lake Victoria identified the dissolution of natural carbonatic volcanic rock encrusting the eastern part of Lake Victoria as the major pollution driver to the gulf and with the findings published in Guya, F. J. (2020).
• A novel study on water hyacinth (Pontederia crassipes), that for a long time posed great socioeconomic drawbacks within Nyanza Gulf, identified eco-friendly management option that stressed on environmental manipulation through decommissioning of a causeway that blocked the only alternative hydrological exchange pathway thereby reducing the pollutant's residence time. The implementation of the recommendations met with efficacious results that has improved Nyanza Gulf's ecology. The publication is contained in Guya, F. J. (2024).
• Just like other East African Rift System lakes, Lake Victoria water levels have been rising since 2006 with devastating results to peripheral structures. A study conducted in 2024 on the socio-economic impact of the rising water levels discovered paradoxical outcome, with also associated improved fish biomass across the four studied species of Nile perch, Haplochromines, Dagaa and Caridina within the three East Africa countries of Kenya, Uganda and Tanzania. Tanzania exhibited the best improvement followed by Kenya and lastly Uganda. Causes and reasons are outlined in the KMFRI Technical report KMF/KSM/RS/2024/25/C4.vii and referenced as: Guya F., Wawiye P., Last J., Basweti G., Aura C., Nyamweya C., Mziri V., Onduso G., Miniga S. & Ogonda, C. (2024). Trends in surface area and lake level variations and their impact on fishery in Lake Victoria, for informed management. Technical report KMF/KSM/RS/2024/25/C4.vii. Kenya Marine and Fisheries Research Institute (KMFRI). 36 pp.

• ▹ Supervision of graduate and post-graduate students who are attached or interns at KMFRI
• ▹ Chair of the internal seminar committee (Kisumu Centre)

• ▹ Aquatic Health Assessment
• ▹ Lake Sedimentation
• ▹ Paleo-limnology
• ▹ Climate Change

• ▹ Certificate – University of Singapore, Singapore, 1998
• ▹ M.Sc. in Marine Geochemistry – University of Victoria, Canada, 1993-1995
• ▹ B.Sc. – University of Nairobi, Kenya, 1988-1991

• ▹ Member – British Ecological Society (BES)
• ▹ Member – Eastern Africa Water Association (EAWA)

• ▹ 2003 - Date: Kenya Marine and Fisheries Research Institute – Assess aquatic health using both neo and paleolimnological data and its ecological impact
• ▹ 2014 - Date: Lakes and Reservoirs: Research and Management Journal – Appointed as a reviewer
• ▹ 2025 - Date: Journal of Great Lakes Research – Appointed as a reviewer