Browsing by Author "Mangi, Halima O."

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Fish productivity response to water quality variations: A case study of nyumba ya mungu dam, in pangani water basin, Tanzania
(Hindawi, 2023) Mangi, Halima O.; Onywere, Simon M.; Kitur, Esther C.
Fish habitat degradation, such as water pollution due to the rapid expansion of incompatible land uses, is one of the noteworthy challenges to freshwater ecosystems. Elevated contents of nutrients and contaminants in water are some of the imperative challenges. Tis research was conducted to investigate the link between water qualities and fsh productivity in the Nyumba ya Mungu Dam, whose fshery potential had decreased by 95% between 1972 and 2018. Physicochemical characteristics, namely, temperature, pH, dissolved oxygen (DO), turbidity, total nitrogen, total phosphorus, chlorophyll a, and the water depth of fshing net location, were assessed following standard procedure. Fish catches per unit efort representing fsh biomass/productivity were monitored for twelve months from January to December 2019. Pearson’s correlation analysis indicated that fsh catch per unit efort was positively and signifcantly correlated with turbidity (r = 0.461, P < 0.01) and TP (r = 0.405, P < 0.01). Stepwise multiple regression model results indicated that turbidity, dissolved oxygen, and the depth of the fshing net location are the statistically signifcant predictors of fsh catch per unit efort which represented fsh biomass. Findings further indicated that the model combining turbidity and dissolved oxygen predicted a 24% change in fsh catch per unit efort, whereas turbidity, dissolved oxygen, and the depth of fshing net location contributed a 28.9% change in fsh catch per unit efort. In conclusion, fsh productivity in the NMD is limited by organic matter availability and nutrient levels that cause algae bloom occurrence. Turbidity is an indicator of organic matter availability and the efect of algae bloom on fsh productivity. Infow of nutrients to the dam nourishes the algae biomass, thus creating vicious cycles on fsh productivity as fsh species in the dam failed to take advantage of high primary production by algae.
Governance systems and natural resource management quality in Tanzania: a cross-sectoral review of evolution, challenges, and pathways for reform
(Sokoine University of Agriculture, 2025) Mangi, Halima O.; Muhanga, Mikidadi I.; Chingonikaya, Emanuel E.; Salanga, Raymond J.
Natural resources, including forests, water, wildlife, and fisheries, are central to Tanzania’s socio-economic development and the livelihoods of its rural population. Over recent decades, governance of these resources has shifted from centralized state-led models toward more inclusive, decentralized, and community-based systems in response to environmental degradation and sustainability imperatives. Despite reforms such as Participatory Forest Management (PFM) and Wildlife Management Areas (WMAs), persistent challenges, including institutional fragmentation, elite capture, legal ambiguities, and limited local capacity, continue to undermine governance effectiveness. This study provides a wide-ranging, cross-sectoral review of the evolution, challenges, and future directions of natural resource governance in Tanzania. Grounded in institutional economics, political ecology, and participatory governance theories, it examines how different governance systems, state-led, co-management, community-based, and hybrid models, affect the quality and equity of resource management across forestry, wildlife, water, and fisheries sectors. Through a narrative synthesis of peer-reviewed and grey literature (2000–2025), the study evaluates governance quality using dimensions such as transparency, accountability, inclusiveness, and fairness. Findings indicate that participatory approaches have contributed to reduced illegal activities and increased local revenues, but these gains are often constrained by weak legal frameworks, limited institutional autonomy, and inconsistent enforcement. The paper concludes by proposing an integrated governance framework based on polycentric and adaptive principles, emphasizing two focused recommendations: (i) harmonizing sectoral laws to secure community tenure and clarify mandates, and (ii) investing in the autonomy and capability of local institutions to ensure equitable and sustainable resource governance.