preliminary studies on impacts of ocean acidification on diversity of fish species landed by artisanal

124 Pages·2015·2.83 MB·English

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PRELIMINARY STUDIES ON IMPACTS OF OCEAN
ACIDIFICATION ON DIVERSITY OF FISH SPECIES LANDED BY
ARTISANAL AND SEMI-INDUSTRIAL FISHERIES AND
COASTAL COMMUNITY LIVELIHOODS IN GHANA

A Thesis submitted to the Department of Marine and Fisheries Sciences
of the University of Ghana

By

EDNA EKUA KWANSIMA QUANSAH
(10243521)

In Partial Fulfilment of the Requirements for the Award of

MASTER OF PHILOSOPHY
In
FISHERIES SCIENCE

JULY, 2014
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DECLARATION
This is to certify that this thesis is the result of research undertaken by Edna Ekua
Kwansima Quansah towards the award of the Master of Philosophy in Fisheries Science
in the Department of Marine and Fisheries Sciences, University of Ghana, under the
supervision of Prof. F.K.E. Nunoo, Prof. P.K Ofori-Danson and Dr. E.E. Onumah. I
hereby declare that except for references to work of other scholars that have been duly
cited, this thesis is entirely my original research which has neither been presented in
whole nor in part to any other university for the award of a degree.

………………………………. Date……………………
Edna Ekua Kwansima Quansah
(Student)

................................................... Date……………………
Prof. F.K.E. Nunoo
(Principal supervisor)

………………………………… Date……………………
Prof. P.K. Ofori-Danson
(Co-supervisor)

………………………………… Date……………………
Dr. E. E. Onumah
(Co-supervisor)
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DEDICATION
This work is dedicated to God Almighty, my parents, Mr. and Mrs. Quansah, and
siblings. God bless you for your love and support throughout my educational life.
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ACKNOWLEDGEMENTS
I wish to express my heartfelt appreciation to God Almighty, who has been my pillar of
strength throughout my educational life.

Sincerest appreciation goes to my principal supervisor, Prof. F.K.E. Nunoo of the
Department of Marine and Fisheries Sciences for his advice and support throughout my
Masters programme and for this thesis. Special thanks go to my co-supervisors Prof. P.K.
Ofori-Danson of the Department of Marine and Fisheries Sciences and Dr. E.E. Onumah
of the Department of Agricultural Economics and Agribusiness for their advice and
guidance in this work. I am grateful to the International Atomic Energy Agency for
funding this project, under the Co-ordinated Research Project (CRP) number K41012
and Contract number 17539. Sincere gratitude also goes to my mentor, Dr. Mrs.
RoseEmma M. Entsua-Mensah, and Dr. Ansah-Asare, both of the Council for Scientific
and Industrial Research (CSIR) for their guidance and advice during the study.

I appreciate the efforts of Messrs. J. Akomeah, E. Klubi, M. Boateng and K. Enyan, all
of the Department of Marine and Fisheries Sciences for their assistance on the field and
in the laboratory. My deepest appreciation goes to Messrs. Daniel Acquah-Lamptey and
Jones Quartey of the Department of Animal Biology and Conservation Science and
Nicholas Ashiabi of Department of Economics for assisting with my data analysis.

To my parents and entire family who believed in me and supported me in diverse ways, I
say God richly bless you.
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TABLE OF CONTENTS
Page #
DECLARATION ........................................................................................................... ii
DEDICATION .............................................................................................................. iii
ACKNOWLEDGEMENTS .......................................................................................... iv
TABLE OF CONTENTS .............................................................................................. v
LIST OF FIGURES…………………………………………………………...……..viii
LIST OF TABLES ......................................................................................................... x
LIST OF PLATES ....................................................................................................... xii
ABSTRACT ............................................................................................................... xiii
CHAPTER ONE ............................................................................................................ 1
1.0 INTRODUCTION .............................................................................................. 1
1.1 Background ......................................................................................................... 1
1.2 Objectives ........................................................................................................... 4
1.3 Justification ......................................................................................................... 4
CHAPTER TWO ........................................................................................................... 7
2.0 LITERATURE REVIEW ................................................................................... 7
2.1 Global Increase in Carbon Dioxide Emissions and
Climate Change .................................................................................................. 7
2.2 Ocean Acidification .......................................................................................... 10
2.2.1 The chemistry behind Ocean acidification ....................................................... 11
2.2.2 Indicators of Ocean acidification ...................................................................... 14
2.2.3 Evidence of ocean acidification occurrence ..................................................... 15
2.3 Impacts of Ocean Acidification ........................................................................ 17
2.3.1 Biological and ecosystem impacts of ocean acidification ................................ 17
2.3.2 Impacts of ocean acidification on fish diversity ............................................... 24
2.3.3 Socioeconomic impacts of Ocean acidification ................................................ 25
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2.4 The Fisheries Sector and Fish Diversity in Ghana ........................................... 27
CHAPTER THREE ..................................................................................................... 30
3.0 MATERIALS AND METHODS ..................................................................... 30
3.1 Sampling Strategy ............................................................................................. 30
3.2 Description of Study Area ................................................................................ 31
3.2.1 Teshie Sangonaa Fish Landing beach ............................................................... 31
3.2.2 Tema Inshore Fishing Harbour ......................................................................... 31
3.3 Biological/Physico-Chemical Data Collection
and Laboratory Procedures ............................................................................... 33
3.3.1 Species composition ......................................................................................... 33
3.3.2 Physico-chemical parameters ........................................................................... 34
3.3.3 Ichthyoplankton Biomass and Composition ..................................................... 38
3.4 Socioeconomic data collection ......................................................................... 39
3.5 Data Analysis .................................................................................................... 40
3.5.1 Biological/Physico-chemical data .................................................................... 40
3.5.2 Socioeconomic data .......................................................................................... 41
CHAPTER FOUR ....................................................................................................... 44
4.0 RESULTS ......................................................................................................... 44
4.1 Physico-chemical Parameters ........................................................................... 44
4.1.1 Significant Physico-chemical Parameters affecting
Biological Variations ........................................................................................ 48
4.2 Species Composition and Abundance .............................................................. 52
4.2.1 Shellfish abundance .......................................................................................... 60
4.2.2 Relationship between Environmental Variables and
Species Abundance ......................................................................................... ..62
4.3 Ichthyoplankton Abundance ............................................................................. 69
4.4 Degree of Human Reliance on the Two Fisheries as
Sources of Livelihoods ..................................................................................... 70
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CHAPTER FIVE ......................................................................................................... 76
5.0 DISCUSSION ................................................................................................... 76
5.1 Extent and magnitude of impacts of ocean acidification
on abundance and diversity of fish species
using physico-chemical parameters ..................................................................76
5.1.1 Impacts of Ocean Acidification on Shellfish
Abundance ........................................................................................................ 82
5.2 Impacts of Ocean Acidification on Ichthyoplankton
Abundance ........................................................................................................ 83
5.3 Degree of Human Reliance on the Two Fisheries as
Sources of Livelihoods ..................................................................................... 84
CHAPTER SIX ............................................................................................................ 87
6.0 CONCLUSION AND RECOMMENDATIONS ............................................. 87
6.1 Conclusion ........................................................................................................ 87
6.2 Recommendations ............................................................................................. 87
REFERENCES ............................................................................................................ 89
APPENDICES ........................................................................................................... 100

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LIST OF FIGURES
Page #
Figure 1: Map showing the selected study sites…………………………....................32
Figure 2: Trend of seawater carbonate chemistry parameters for the
artisanal fishery during the lean and peak fishing seasons
of year 2013……...........................................................................................46
Figure 3: Trend of seawater carbonate chemistry parameters for the
semi-industrial fishery during the lean and peak fishing
seasons of year 2013………................................................................….....46
Figure 4: Trend of ocean acidification indicators for the artisanal
fishery during the lean and peak fishing seasons of
year 2013..........….........................................................................................47
Figure 5: Trend of ocean acidification indicators for the semi-
industrial fishery during the lean and peak
fishing seasons of year 2013.........................................................................47
Figure 6: PCA showing relationship between fishery and seasons
sampled and the six principal variables………………................................52
Figure 7: Relative abundance of various fish families in the
artisanal fishery....…….................................................................................59
Figure 8: Relative abundance of various fish families identified
in the semi-industrial fishery…………………..........................…………...59
Figure 9: CCA biplot showing relationship between dominant
fish species identified in the lean season of the artisanal
fishery.............................................................................................................63
Figure 10: CCA biplot showing relationship between rare fish species
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identified in the lean season of the artisanal fishery.....................................64
Figure 11: CCA biplot showing relationship between dominant
fish species identified in the peak season of the artisanal
fishery…...…...................................................................................................65
Figure 12: CCA biplot showing relationship between rare fish
species identified in the peak season of the artisanal fishery…….........…...66
Figure 13: CCA biplot showing relationship between dominant fish
species identified in the lean season of the semi-industrial
fishery…….....................................................................................................67
Figure 14: CCA biplot showing relationship between dominant fish
species identified in the peak season of the semi-industrial
fishery............................................................................................................68
Figure 15: CCA biplot showing relationship between rare fish species
identified in the peak season of the semi-industrial fishery..........................68
Figure 16: Seasonal means of total ichthyoplankton abundance in the
artisanal fishery (error bars represent standard deviation)............................ 69
Figure 17: CCA biplot of identified fish larvae in the peak season of the
artisanal fishery…………………….........………………………………......70

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LIST OF TABLES
Page #
Table 1: Mean (± standard deviation) values of physico-chemical
parameters measured in the lean and peak seasons of both
fisheries in the year 2013.……………………….....................……………....45
Table 2: Summarised PCA values on Physico-chemical parameters
that relate with species abundance in the two fisheries for
both seasons......................................................................................................50
Table 3: Principal component scores for fishery/season which
loaded on selected principal components ……....…………………………......51
Table 4: Occurrence of fish species in the artisanal and
semi-industrial fisheries during the lean and peak
fishing seasons of year 2013.……………………...........................…………..53
Table 5: Species composition and relative abundance of species
found in the artisanal fishery for year 2013.......................................................56
Table 6: Species composition and relative abundance of species
found in the semi-industrial fishery during the lean and
peak fishing seasons of the year 2013..............................................................58
Table 7: Abundance and relative abundance of crustaceans and
molluscs in the artisanal fishery…………………...........................................60
Table 8: Ranked diversity indices for both seasons in both fisheries
[Highest score = 4 and least score = 1, in brackets]………….........................62
Table 9: Demographics of respondents………………………………………………..71
Table 10: Summary statistics of respondents ………………………………..................72
Table 11: Fish species preference of respondents during the lean
x