ARCHIVES
VOL. 8, ISSUE 1 (2026)
Ecological silence in Ibadan drainages: Degradation, fish extinction and restoration pathways
Authors
Ogundeji Obadara Emmanuel, Ogbuagu Samuel Ifeanyi, Chindo Jimkuta, Kargbo Esther Edith, Yusuff Babatunde Raji
Abstract
Ibadan’s Ona-Ogbere-Ogunpa drainage network
has been established to be an ecologically collapsed, pollution-dominated urban
conveyance system, despite its potential to sustain artisanal fisheries and
floodplain livelihoods. Multiple lines of evidence from chronic organic
loading, severe hypoxia, persistent heavy-metal contamination, physical channel
simplification, and episodic biocide use indicate that this ecological
degradation has driven beyond declines to localized extinction of historically native
fish assemblages within the urban reaches of the basin system. Contemporary
surveys repeatedly report toxic conditions and absent ichthyofauna, while
nearby, less-degraded waters both within and outside the same Ogun basin retain
diverse fish communities, underscoring that current environmental thresholds in
Ibadan’s streams are incompatible with recolonization. Situated within the
broader context of urban stream syndrome and freshwater biodiversity erosion in
rapidly urbanizing regions, this review assembles hydrological, chemical,
biological, and governance evidence to diagnose drivers of functional
ecological collapse in the Ona-Ogbere-Ogunpa system. It further synthesizes
regional records to infer lost species and trophic guilds, and draws on international
experience, especially urban-river restoration, sponge-city concepts, and
nature-based infrastructure, all being Chinese models, to outline a
context-appropriate pathway that couples pollution prevention, sediment and
habitat rehabilitation, waste-to-energy solutions, and institutional
accountability. The review also highlights an urgent need for dedicated
ichthyofaunal surveys along the Ona, Ogbere, and Ogunpa channels to establish
current species baselines and provide benchmarks for assessing local extinction
and future recovery. Ultimately, it argues that the recovery of Ibadan’s rivers
must be evaluated not by cosmetic improvements in water appearance alone but by
measurable restoration of trophic complexity and the verified return of native fish
species as indicators of renewed socio-ecological function.
Download
Pages:61-70
How to cite this article:
Ogundeji Obadara Emmanuel, Ogbuagu Samuel Ifeanyi, Chindo Jimkuta, Kargbo Esther Edith, Yusuff Babatunde Raji "Ecological silence in Ibadan drainages: Degradation, fish extinction and restoration pathways". International Journal of Ecology and Environmental Sciences, Vol 8, Issue 1, 2026, Pages 61-70
Download Author Certificate
Please enter the email address corresponding to this article submission to download your certificate.