Enhancing Profitability of Pond Aquaculture in Ghana through Resource Management and ...

243 Pages·2014·3.24 MB·English

Enhancing Profitability of Pond Aquaculture in Ghana through Resource
Management and Environmental Best Management Practices

Yaw Boamah Ansah

Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State
University in partial fulfillment of the requirements for the degree of

Doctor of Philosophy
In
Fisheries and Wildlife

Emmanuel A. Frimpong, Chair
Eric M. Hallerman
Stephen H. Schoenholtz
Kurt Stephenson

October 30, 2014
Blacksburg, VA

Keywords: Effluent management; Tilapia growth models; Information-theoretic
statistics; Innovation adoption; Economic impact assessment; Economic surplus;
Enterprise budget; Monte Carlo simulations; Environmental impact

Copyright, Yaw B. Ansah
Enhancing Profitability of Pond Aquaculture in Ghana through Resource Management and
Environmental Best Management Practices

Yaw Boamah Ansah

ABSTRACT

The accelerating pace of growth of aquaculture in sub-Saharan Africa has received much
positive appraisal because of the potential of the industry to contribute to economic development
and food security by providing jobs and animal protein. Adoption of best management practices
(BMPs) holds the potential to ameliorate the related environmental impacts of aquaculture, such
as in the amounts of nutrients and sediment that will enter natural water bodies from earthen
pond effluents. The goals of this study were to characterize adoption of aquaculture BMPs on
small-scale, pond-based farms in Ghana, and to assess selected economic, social, and
environmental outcomes of BMP adoption. Two BMPs: 1) water reuse, and 2) commercial
floating feeds, were investigated for adoption by pond-based fish farmers in Ghana. I conducted
my study in Ghana using on-farm experiments involving intensive monitoring of water quality
and growth of Nile tilapia (Oreochromis niloticus) over two production cycles. Additionally, I
administered a baseline survey to 393 (and a follow-up survey to 160) fish farmers. I determined
the best model for modelling farmed Nile tilapia growth with multi-model inference based on
Akaike information criterion (AIC), the profitability of adopting BMPs with stochastic enterprise
budgets and, social welfare impact with the Economic-Surplus model. I used a Markov model to
predict the equilibrium rate of adoption of the two BMPs and determined the impact of BMP
adoption on the reduction of pollutant loading with the Minimum-Data method of the Tradeoffs
Analysis (TOA-MD).
My results showed that the logistic model is a better alternative to the von Bertalanffy model for
modelling the growth of Oreochromis niloticus under pond aquaculture conditions. There were
no significant differences in fish weight between the water re-use BMP and the use of new water.
Adoption of the commercial floating feed BMP resulted in a 100% increase in fish final weight
and yield, and in higher profitability, compared to the sinking feed type. Probability of making a
profit was highest (72%) in the scenario with commercial feed and self-financing. Net present
values (NPV) of about US$ 11 million and US$ 375 million could be obtained from the adoption
of commercial floating feed and Genetically-Improved Farm Tilapia (GIFT) strain,
respectively, in Ghana. Hence, any innovation that has a significant impact on fish yield also
will have a significant impact on mean NPV and social welfare. However, I identified a
number of potential negative ecological and genetic impacts that exist from introducing the
GIFT strain into Africa from Asia. Although considered low-intensity production systems,
nutrients and solids in study ponds were found to be higher than levels expected in intensive
culture ponds by wide margins. Pond water quality was significantly higher with commercial
floating feed. The water-reuse BMP also prevented pollutants from leaving ponds altogether
for the number of cycles for which pond water was reused, especially if associated BMPs
such as rainfall capture and avoidance of water exchange are observed. Significant reductions
in the loading of all water quality variables (nitrogen, phosphorus, solids, and BOD ) could
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be achieved with the adoption of the recommended feed type in Ghana. Adoption of the water
reuse BMP has the potential to cause pollution reductions of 200% - 3,200% above that from
the floating feed BMP. The strongest influence on the combined adoption of these BMPs
were from : farmer’s awareness of the feed BMP, perceived necessity and relative
profitability of the water reuse BMP, and farmer’s years of experience. A combination of
central media (workshops), demonstrations, and lateral diffusion was found to be the most
effective channel for disseminating these BMPs. Maximum adoption rate of the feed BMPs
was estimated to be 38% - 58%. Also, US$ 6,000/year and US$12,000/year need to be paid
per 0.6 ha pond surface area to push adoption of the feed BMP to 50% and 70%, respectively.
Hence, to ensure the successful adoption of aquaculture BMPs, I recommend that regular
well-planned workshops be organized to create awareness and a conducive atmosphere to
target farmers at multiple stages of the innovation decision process. Incentives and effective
dissemination will encourage the adoption of these and other environmental BMPs. Feed
costs need to be lowered in order to encourage the adoption of commercial floating feed in
Ghana. Future analyses could quantify the differences in production costs between using the
two water types, to reveal the possible higher relative profitability of pond water reuse over
draining ponds after each production cycle. Also, African governments are advised to
commission rigorous baseline and ecological risk analyses before adoption of the GIFT strain
from Asia. Improvements in management practices and infrastructure could increase the yield
and profitability of the local strains even if genetically-improved strains are not introduced.

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ACKNOWLEDGEMENTS
To God be the glory.
I never anticipated being at Virginia Tech (VT) for six years, but Emmanuel Frimpong made
it difficult to leave after my master’s degree. I am grateful for his patience and diverse
knowledge to guide me through my several interdisciplinary projects, be it ecology, statistics,
economics, policy, or aquaculture. I am well-aware of the sacrifices he makes daily to ensure
his students are all doing well, from rides to and from the airport, writing several detailed
recommendation letters on short notice, and a willing, listening ear. I appreciate his help and
encouragement to seize opportunities for my professional and career development, urging me
on towards this PhD, two master’s degrees (Conservation and Economics), a graduate
certificate (International Development), and a number of awards and fellowships. My stay at
Virginia Tech has been fruitful, and this success will not have been possible without the help
of my mentor, friend, and academic advisor.
Special thanks to my doctoral committee for helping me over the years, individually and as a
group, with advice, degrees, awards, publications, and with my general academic
progression. I couldn’t have picked a better committee. Stephen Schoenholtz’s sage advice
led to my staying at VT for four more years after helping me think through a number of
factors to decide where to go for my PhD. Stephen has been great with suggesting classes to
meet proficiency gaps, and was very helpful, especially with the pond water quality
component of my dissertation project. Eric Hallerman was the head of department almost
throughout my stay at VT, and despite his busy schedule, he was always available to sit and
talk. Two things I will remember about Eric is his attention to detail, and his extremely quick
and detailed revision of my drafts (including the references section!). Kurt Stephenson
always has been available to talk about my dissertation and professional development. He has
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been influential in my interests in applied economics, which led to my getting my MS in
Agricultural and Applied Economics, while enrolled for my PhD.
A big thank you to the following for contributing funding towards my PhD, travel, and
general professional activities over the last four years: AquaFish Innovation Lab, Virginia
Tech (VT) Graduate School, United States Agency for International Development (USAID),
Department of Fish and Wildlife Conservation at VT (VT-FIW), Norman E. Borlaug
Leadership Enhancement in Agriculture Program (LEAP) Fellowship.
I would like to thank professors, students, staff, and field and laboratory technicians from
both Virginia Tech Department of Fish and Wildlife Conservation (VT-FIW, U.S.A), and the
Department of Fisheries and Watershed Management at Kwame Nkrumah University of
Science and Technology (FWM-KNUST, Ghana), who helped me either in administrative
matters or in accomplishing field work and other duties in the two countries. I am especially
grateful to Stephen Amisah, Dean of FWM-KNUST, for his continuous advice,
encouragement, and the willingness to ensure that my summer field seasons in Ghana were
successful. Daniel Adjei-Boateng, Nelson Agbo, and Gifty Anane-Attu from FWM-KNUST,
have also helped me with their expertise, recommendation letters, and encouragement over
the years. I also am indebted to Dana Keith, Terri Waid, and Susan Archer from VT-FIW for
always been available to help with administration issues.
I would also like to acknowledge my parents, Jacob and Mercy, and my siblings for their
support and encouragement throughout my academic pursuits. Special thanks to my elder
brother, Kofi, without whom I will not have gotten this far. I also am grateful to Emmanuel
and Sophia Frimpong, John and Lucy Copeland, Stephen and Gloria Schoenholtz, and several
other families and individuals in Blacksburg who opened their hearts and their homes to me
to ensure that my stay at VT was an enjoyable one.
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Last, but not the least, special thanks go to the graduate students in the Frimpong Lab at VT-
FIW, Steve Watkins, Brandon Peoples, Iris Fynn, Stephen Floyd, Jian Huang, and Joseph
Buckwalter. I wish you the best in all your endeavors.

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ATTRIBUTION
A number of co-authors contributed significantly to this dissertation, which is a compilation
of seven publications and manuscripts. This section specifies the contributions of each co-
author to this work. E.A. Frimpong is my academic advisor and primary project supervisor.
He wrote the grant to fund this study, and contributed heavily to the project design, analysis
and writing of each manuscript.
Stephen Amisah, Daniel Adjei-Boateng, Nelson W. Agbo and Hillary Egna co-authored
Chapter 2, which published in Sustainability in February 2014. This paper was the result of
two separate projects of the AquaFish Innovation Lab, and co-authors were the team
members who were involved in the conception, data collection, analysis, and writing of the
manuscript.
Gifty Anane-Taabeah Attu and Regassa E. Namara served as co-authors on Chapter 4. Gifty
played a key role in survey administration, workshop organization, data collection, and
writing of this manuscript. Regassa co-supervised the Borlaug LEAP Fellowship that
contributed funding for my study. He contributed to the development of survey instruments,
data analysis and writing of this chapter.
Eric M. Hallerman co-authored Chapter 8, which published in Sustainability in June 2014. He
contributed the sections on Genetics, and also to the overall design and writing of the
manuscript.
The following chapters are to be submitted to the following journals for publication: Chapter
3: North American Journal of Aquaculture, Chapters 4: Technological Forecasting and Social
Change, Chapter 5: Aquaculture Economics and Management, Chapter 6: International
Journal of Sustainable Development, and Chapter 7: Journal of Environmental Management.
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Table of Contents

ABSTRACT ........................................................................................................................... ii
ACKNOWLEDGEMENTS .................................................................................................. iv
ATTRIBUTION ................................................................................................................... vii
List of Figures ......................................................................................................................... xii
List of Tables ......................................................................................................................... xiv
Chapter 1: General Introduction ........................................................................................... 1
Aquaculture and best management practices ......................................................................... 1
This dissertation ..................................................................................................................... 2
Ghana ..................................................................................................................................... 6
Fish farming in Ghana ........................................................................................................... 7
Bottlenecks to fish farming in Ghana .................................................................................... 7
Funding sources for fish farming in Ghana ........................................................................... 8
Chapter 2: Effects of Two Environmental Best Management Practices on Pond Water
and Effluent Quality and Growth of Nile Tilapia, Oreochromis niloticus ........................ 10
Abstract ................................................................................................................................ 10
Keywords ............................................................................................................................. 11
Introduction .......................................................................................................................... 11
Experimental ........................................................................................................................ 15
Study Location ................................................................................................................. 15
Experiment Setup and Monitoring ................................................................................... 15
Statistical Analysis ........................................................................................................... 22
Results and Discussion ........................................................................................................ 23
Conclusions .......................................................................................................................... 40
Acknowledgments................................................................................................................ 41
Conflicts of Interest.............................................................................................................. 41
References ............................................................................................................................ 41
Chapter 3: Using Model-Based Inference to Select a Predictive Growth Curve for
Farmed Tilapia ....................................................................................................................... 45
Abstract ................................................................................................................................ 45
Introduction .......................................................................................................................... 46
Methods................................................................................................................................ 51
Data .................................................................................................................................. 51
Model selection procedure ............................................................................................... 51
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Growth prediction and model validation ......................................................................... 52
Results .................................................................................................................................. 53
Model selection ................................................................................................................ 53
Prediction and validation ................................................................................................. 54
Discussion ............................................................................................................................ 56
Average growth curve vs fitted growth curve .................................................................. 56
Model selection and validation ........................................................................................ 56
Implication for profitability assessment of tilapia farming.............................................. 61
Acknowledgements .............................................................................................................. 62
References ............................................................................................................................ 63
Chapter 4: Characterization of the Adoption of Environmental Best Management
Practices in Pond Aquaculture ............................................................................................. 65
Abstract: ............................................................................................................................... 65
Keywords: ............................................................................................................................ 66
Introduction .......................................................................................................................... 66
Experimental section ............................................................................................................ 71
The ordered logistic model .............................................................................................. 71
Probability of adoption and utility maximization ............................................................ 71
Data collection and modeling .......................................................................................... 72
Results and Discussion ........................................................................................................ 78
Characteristics of BMP adopters ..................................................................................... 78
Characterizing the rate of BMP adoption ........................................................................ 83
Relative effectiveness of innovation diffusion channels ................................................. 85
Conclusions .......................................................................................................................... 90
Acknowledgements .............................................................................................................. 91
References ............................................................................................................................ 92
Chapter 5: Comparison of the Profitability of Alternative Management Practices for
Pond Tilapia Farms ............................................................................................................... 95
Abstract ................................................................................................................................ 95
Keywords ............................................................................................................................. 96
Introduction .......................................................................................................................... 96
Study background and rationale....................................................................................... 96
Modifications to traditional enterprise budgets ............................................................... 97
Methods................................................................................................................................ 99
Data .................................................................................................................................. 99
Price function ................................................................................................................. 100
Harvest weight function ................................................................................................. 101
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Key definitions and computations ................................................................................. 102
Risk / Sensitivity Analysis ............................................................................................. 103
Results ................................................................................................................................ 104
Deterministic enterprise budget analyses....................................................................... 104
Stochastic enterprise budget analysis / uncertainty analysis .......................................... 106
Sensitivity analysis......................................................................................................... 108
Discussion .......................................................................................................................... 108
Conclusions ........................................................................................................................ 112
Acknowledgements ............................................................................................................ 113
References .......................................................................................................................... 114
Chapter 6: Impacts of the adoption of BMPs on social welfare: a case study of
commercial floating feeds for pond culture of tilapia in Ghana ...................................... 124
Abstract .............................................................................................................................. 124
Keywords ........................................................................................................................... 125
Introduction ........................................................................................................................ 125
Methods/Data Analysis ...................................................................................................... 130
Model ............................................................................................................................. 130
Data and Key Assumptions ............................................................................................ 131
Analysis.......................................................................................................................... 135
Results ................................................................................................................................ 136
Discussion .......................................................................................................................... 138
Conclusions ........................................................................................................................ 141
Acknowledgements ............................................................................................................ 142
References .......................................................................................................................... 142
Chapter 7: Impacts of Aquaculture BMP Adoption on Loading of Nutrients and
Sediment in Ghana ............................................................................................................... 145
Abstract .............................................................................................................................. 145
Introduction ........................................................................................................................ 146
The minimum-data method of the Tradeoffs Analysis (TOA-MD) .................................. 148
Methods/Analysis .............................................................................................................. 150
Results ................................................................................................................................ 153
Discussion .......................................................................................................................... 155
Conclusion ......................................................................................................................... 159
Acknowledgements ............................................................................................................ 159
References .......................................................................................................................... 160
Chapter 8: Genetically-Improved Tilapia Strains in Africa: Potential Benefits and
Negative Impacts .................................................................................................................. 162
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