African Journal of Fisheries and Aquatic Resources Management

Optimization of Paddle Wheel Aerator Parameters for Enhanced Aquaculture Water Quality Using Response Surface Methodology Techniques

O. B. ODUNTAN — Mon, 22 Sep 2025 00:00:00 +0000

Water quality plays a pivotal role in the efficient management of aquaculture systems, particularly
through the regulation of dissolved oxygen (DO) levels. This study focuses on the
modification and performance evaluation of a locally fabricated mechanical paddle wheel
aerator for optimizing fish pond agitation and oxygenation. Key operational parameters
investigated include rotational speed (300–600 rpm), paddle submersion depth (0.1–0.2
m), and inclination angle (15°–45°). The aerator was tested in a 2,000 L concrete pond
(1×2×1 m) with a stocking density of 300 fish/m³ using unsteady-state aeration tests. Results
were statistically analyzed using Design Expert Software (2022) with ANOVA at p<
0.05. Maximum Standard Aeration Efficiency (SAE) of 5.856 kg O/kWh was achieved at
450 rpm, 0.2 m depth, and 45° inclination, while the highest Standard Oxygen Transfer
Rate (SOTR) was 5.656 kg O/h at 600 rpm. The findings demonstrate that optimized paddle
wheel design and configuration significantly improve aeration performance, offering a
cost-effective solution for enhancing water quality in pond-based aquaculture systems.

Implementation of the FAO Port State Measures Agreement in Combating IUU Fishing in West Africa: The Case of Nigeria

Y. E. AGBEJA — Mon, 22 Sep 2025 00:00:00 +0000

Illegal, Unreported, and Unregulated (IUU) fishing threatens marine resources, food security,
and governance in West Africa, where an estimated 37% of fish harvests are illicit.
The FAO Port State Measures Agreement (PSMA), adopted in 2009, is the first binding international
treaty to combat IUU fishing by restricting port access, mandating inspections,
and promoting information sharing. Nigeria’s accession in October 2022 was a milestone
for regional compliance, closing a critical enforcement gap within the Fisheries Committee
for the West Central Gulf of Guinea (FCWC). This study applies a governance implementation
framework, grounded in institutional and compliance theory, to assess Nigeria’s
progress through legal alignment, institutional capacity, and operational readiness.
Content analysis of legislation, policy documents, and institutional arrangements shows
early reforms, including a draft Fisheries Bill, designation of entry ports, and pilot inspections.
However, significant challenges remain: outdated laws, limited inspectorate
resources, fragmented interagency coordination, and weak integration with FAO’s Global
Information Exchange System (GIES). Nigeria is therefore positioned as a proactive but
capacity-limited PSMA Party. Sustained reforms, institutional investment, technological
modernization, and stronger regional cooperation are essential to operationalize commitments,
strengthen fisheries governance, and enhanceWest Africa’s deterrence against IUU
fishing.

Design and Assessment of Heat Exchanger Parameters for Thermal Efficiency in Fish Smoking Kiln

O. B. ODUNTAN — Mon, 22 Sep 2025 00:00:00 +0000

Efficient thermal management in fish smoking kilns is essential for enhancing product quality,
optimizing fuel consumption, and promoting operational sustainability. Conventional
kiln systems frequently suffer from inconsistent heat retention and poor energy utilization
due to suboptimal heat exchanger configurations. This study evaluates the influence
of three key parameters—blower speed (650, 725, and 800 rpm), number of open pipe
inlets (5, 10, and 15), and insulation material (sawdust, clay, and fiber) on the thermal
performance of a locally fabricated heat exchanger integrated into a fish smoking kiln. A
Response Surface Methodology (RSM)-based central composite design was employed to
structure a 20-run experimental matrix, allowing for systematic interaction analysis between
design variables. Airflow rate measurements were taken at the exhaust outlet of
the heat exchanger to ensure consistent thermal load evaluation. Statistical analysis using
ANOVA revealed significant effects (p < 0.01) of blower speed and insulation type on outlet
air temperature, with the maximum temperature of 96?C achieved at 800 rpm, 15 open
pipes, and fiber insulation. Additionally, airflow rate was strongly influenced by both linear
and quadratic terms of blower speed and pipe configuration, with adjusted R2 = 0.995
and Adequate Precision = 79.48, indicating model robustness. This work distinguishes
itself from previous studies by integrating cost-effective materials, a scalable exchanger
design, and a quantitative optimization framework for kiln retrofitting. Its adaptability to
diverse kiln geometries and biomass fuel types underscores its potential for widespread
application across artisanal and semi-industrial fish processing facilities. These findings
offer a replicable pathway for transitioning traditional fish smoking systems toward higher
thermal efficiency and environmental compliance.

Advancing Integrated Fish Farming in Nigeria: Climate-Smart Innovations and Policy Strategies

Y. E. AGBEJA — Thu, 02 Oct 2025 00:00:00 +0000

Nigeria faces a significant gap between fish demand and domestic supply, with imports covering nearly half of consumption. Integrated fish farming offers a pathway to expand production while addressing resource and environmental challenges. This study applies an evidence-based policy analysis of scholarly, institutional, and grey literature published up to 2022. Using the Climate-Smart Aquaculture (CSAq) framework, supported by institutional and diffusion of innovation theories, it assesses both the benefits of emerging technologies and the conditions influencing their adoption. Results show that solar-powered aeration, biofloc systems, and aquaponics can lower costs, improve resilience to climate variability, and reduce environmental impacts. Yet uptake is constrained by limited finance, weak extension support, and inadequate regulatory incentives. The study concludes that targeted reforms in credit access, extension training, and sustainability-focused regulations are essential to scale these innovations. Strengthening such enablers would reduce Nigeria’s fish deficit, enhance food security, and align aquaculture with climate adaptation priorities.

Power Asymmetries and Participation Gaps in InlandWater Governance: Towards Adaptive Co-Management at Eleyele Lake, Nigeria

Y. E. AGBEJA — Fri, 03 Oct 2025 00:00:00 +0000

Sustainable management of inland water bodies depends on the active involvement of diverse
stakeholders whose livelihoods and interests are directly tied to these resources. This
study assessed stakeholder perceptions of participation in the governance of Eleyele Lake,
Ibadan, Nigeria, with the objective of identifying power asymmetries, governance gaps,
and pathways for more inclusive management. Data were collected between February and
August 2018 through a questionnaire survey of 98 respondents; comprising fishermen, fish
traders, government agencies, local businesses, religious groups, and recreational operators,
supplemented by participatory appraisal tools. Stakeholder analysis employed a participation
matrix, an importance–influence grid, and institutional Venn diagrams to map relationships,
dependencies, and decision-making power. Perceptions of participation were
evaluated using Likert-scale measures of being informed, consulted, and involved, with
high internal consistency (Cronbach’s = 0.96). Findings reveal that fishermen and women
fish traders, though highly dependent on the lake, fall into the “high importance–low influence”
category, while government agencies dominate decision-making despite capacity
constraints. Only 20% of respondents reported feeling adequately informed, 7% consulted,
and 5% actively involved in governance. A chi-square test (² = 56.12, df = 4, p ¡ 0.001)
confirmed significant associations between stakeholder group and perceived participation,
underscoring the marginalization of primary users. Shared challenges particularly aquatic
weed proliferation and pollution; emerged as entry points for collective action. The study
concludes that institutionalizing participatory platforms and multi-stakeholder committees
within an adaptive co-management framework is essential to move from symbolic inclusion
toward genuine power-sharing. Embedding inclusive governance in lake management
will not only strengthen ecological sustainability but also enhance livelihood security and
community resilience.