Adelaida Semesi


Adelaida Semesi
Adelaida Semesi
Award year


Project Details

In response to environmental destruction, overfishing and coastal erosion in Tanzania, Semesi used her Pew Fellowship to conduct a major study on the biological resources (mangroves, prawn, fin fish, shell fish, seagrass), socio-economic statistics, and physical and chemical factors in Bagamoyo area, as well as the impacts of human activities on the coastal areas around the Ruvu River. In particular, she focused on the critically important mangroves. This region, approximately 90km north of Dar es Salaam, includes essential estuarine resources for the country and supports active salt production as well as prawn and fin fish fisheries. However, resources, especially mangroves, are severely overexploited. Local resource managers and villagers are not currently capable of sustainably managing the natural capital to support healthy ecosystem functions and community livelihoods.

Semesi's study involved an interdisciplinary team of researchers, university students and community members whose goal is to improve future land use planning and resource management activities which support both environmental and social needs. To foster proper understanding and use of the data, Semesi organized community workshops which included diverse stakeholders from government agencies, coastal villages, environmental NGOs and the private sector. Results were also shared with the broader scientific community through the publication of papers and presentations at international conferences so that efforts in Bagamoyo could serve as a model for other areas.


Adelaida Semesi, a botanist who was also trained in microbiology, worked to develop human resources for Tanzania and the East Africa Region. She taught marine botany, (seagrasses, seaweeds and mangroves), food microbiology and microbial metabolism at the University of Dar es Salaam for over 20 years. Semesi also served as head of the department of Biology and as an associate dean of the faculty. From 1996 to 2000, Semesi was a professor at the Centre for International Environment and Development Studies, University of Norway, while maintaining a teaching affiliation with the University of Dar es Salaam. In 2000, she became the director of the Marine Science Institute in Zanzibar.

Previously, Semesi worked for two years in the Forest and Beekeeping Division of the Tanzania Ministry of Natural Resources where she coordinated the preparation of the management plans of all the mangroves of mainland Tanzania. She also researched natural products and ecology and worked in various laboratories internationally, including the University of South Florida in Tampa, Unilever research company in the UK, University of Nijmegen in the Netherlands, University of Ibadan, Nigeria and the Agricultural University of Norway. She also participated in numerous evaluation teams nationally and internationally.


Adelaida Semesi passed away on February 6, 2001. She was a great scholar in marine sciences. She taught many marine science students at undergraduate and postgraduate levels in Tanzania and abroad. She conducted research and published a lot in areas of seaweeds, seagrasses, mangroves and microbiology. Her scientific contributions in the areas of environmental conservation and sustainable use of natural resources need to be emulated by other scientists. Professor Adelaida Semesi has stimulated the development of many marine science programs in Tanzania and the region. She pioneered research in seaweed, including the farming of seaweed, and developed the National Mangrove Management Plan for Tanzania. Professor Semesi was always in support of the disadvantaged, thus she dedicated most of her lifetime to solving problems of the poor by bringing appropriate scientific results close to the community. Her ability to mix with many coastal communities provided a great inspiration.




Ph.D., University of Dar Es Salaam
1979: Botany, Tanzania

Bachelor of Science, University of Dar Es Salaam
1975: Chemistry & Botany, Tanzania


IUCN, Commission for Ecosystem Management

National Agricultural Food Co-operation (NAFCO)
Board Member

National Environment Management Council of Tanzania
Board Member

Tanzania Marine National Parks, Board of Trustees

Tanzania Commission for Science and Technology (COSTECH)
Member and Chair of the Basic Sciences Research and Development Committee


Marine Fellow
1996: Pew Fellows Program in Marine Conservation

International Foundation for Science Fellowship

Fulbright Scholarship

Rockfeller Foundation Fellowship


International Seaweed Association

Council Member

International Society for Mangrove Ecosystems
Council Member

Western Indian Ocean Marine Science Association (WIOMSA)
Board of Trustees


  • Engdahl, S., F. Mamboya, M. Mtolera, A. Semesi and M. Björk. 1998. The brown macroalgae Pakina boergesenii as an indicator of heavy metal contamination in the Zanzibar Channel. Ambio 27(8): 694-700
  • Semesi, A.K. 1998. Coastal resources utilization and conservation issues in Bagamoyo, Tanzania. Ambio 27(8): 635-644
  • Semesi, A.K. 1998. Mangrove management and utilization in Eastern Africa. Ambio 27(8): 620-626
  • Mtolera, M.S.P., J. Collen and A.K. Semesi. 1996. Stressed-induced production of volatile halogenated organic compounds in Eucheuma denticulatum (Rhodophyta) caused by elevated pH and high light intensities. European Journal of Phycology 31(1): 91
  • Bjork, M., S.M. Mohammed and A. Semesi. 1995. Coralline algae, important coral-reef builders threatened by pollution. Ambio 24(7): 502
  • Collen, J., M. Mtolera, K. Abrahamsson, A. Semesi and M. Pedersen. 1995. Farming and physiology of the red algae Eucheuma: Growing commercial importance in East Africa. Ambio 24(7): 497-450
  • Mtolera, M.S.P., J. Collen and A.K. Semesi. 1995. Destructive hydrogen peroxide production in Eucheuma denticulatum (Rhodophyta) during stress caused by elevated pH, high light intensities and competition with other species. olera, M.S.P., J. Collen and A.K. Semesi. 1995. Destructive hydrogen peroxide production in Eucheuma denticulatum 30(4): 289
  • Semesi A.K. 1993. Wetlands of sub-saharan Africa, their relevance and management. Proceedings of the conference on water and environment: Key to Africa's Development 151-164

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