ABSTRACT
The distribution and abundance of shell fish in Akor river in Ikwuano Local Government Area and Ihie river in Umuahia South Local Government both in Abia State were studied in this research. A total of 2 species of prawns, 3 species of periwinkles, 3 species of mussel, 5 species of crabs and 1 species of apple snail were collected from Akor river, Itunta with totals of 101 prawns, 131 crabs and 243 periwinkles, 49 mussels and 38 apple snails. Conversely, 2 species and a total of 29 crabs were collected from Ihie. There were more species distribution and abundance at Akor river than Ihie river. The species collected from Akor were by literature similar to species endemic in the coastal waters of Cross River and Akwa Ibom. It seems that there is an influx of shell fish from the marine and brackish waters of Cross River into Akor river. Physiochemical parameters of the stream suggests that the stream receives brackish water during rainy season and high tidal periods. The dearth of species in Ihie is indicative of the anthropogenic activities, perturbation and degradation of the previously popular Ihie river fishing ecosystem. This research shows that anthropogenic perturbations lead to reduction in river productivity and serious loss of shell fish populations. Moreover the species abundance in Akor is an asset that should be preserved and managed for sustainable yield
TABLE OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgments v
Table of contents vi
List of tables vii
List of figures viii
CHAPTER 1 INTRODUCTION
1.1
Background of the Study 1
1.2
Statement of Problem 2
1.3
Justification 2
1.4
Objective of the Study 2
CHAPTER 2 LITERATURE REVIEW
2.1 Biodiversity 8
2.2 Factors affecting the abundance and
distribution of shellfish 12
2.2.1 Distribution 12
2.2.2 Abundance 12
2.2.2.1
Impact of human activities 12
2.2.2.2 Predation
and harvesting 12
2.2.3 Sedimentation 12
2.2.4 Other factors 13
2.2.4.1
Concentration of chemicals 13
2.2.4.2 Size of shellfish 13
2.3 Threats 14
2.3.1 Human activities 14
2.3.2 Industrial discharge 14
2.3.3 Exploitation by farmers 14
2.4 Nutritional values of shellfish 15
2.4.1 Fatty acid 15
2.4.2 Calories 16
2.4.3 Omega-3
fatty acid 18
2.4.4 Cholesterol 19
2.4.5 Mineral
and vitamins 20
2.5 Reproductive
Biology 22
2.6 Conservation 24
2.6.1 Problems of aquatic conservation 24
2.6.1.1 Sustainability of fishery resources 24
2.6.2 Other problems of fish resources are 26
2.7 Relative Species Abundance 26
2.8 Water Quality Parameters 27
2.8.1 Temperature 27
2.8.2 Dissolved oxygen (DO) 28
2.8.3 Total dissolved solids (TDS) 28
2.8.4 Electrical conductivity (EC) 29
2.8.5 Hydrogen-ion
concentration (PH) 29
2.9 Shellfishes 30
2.9.1 Crabs 30
2.9.2
Prawn 31
2.9.3 Mussels 33
CHAPTER 3 MATERIALS AND METHODS
3.1 Area of Study 34
3.1.1 Reason for
selection of study areas 37
3.2 Data Collection 38
3.3 Identification of Samples and Experimental
Shellfish 38
3.4 Determination
of Water Quality Parameters 39
3.4.1 Temperature 39
3.4.2 pH 39
3.4.3 Transparency 40
3.4.4 Depth 40
3.4.5 Dissolved
oxygen 40
3.4.6 Current
velocity 40
3.4.7 Biological
oxygen demand (BOD) 40
3.4.8 Heavy
metals 41
3.5 Statistical
Analysis 41
CHAPTER 4 RESULT AND DISCUSSION
4.1 Result 42
4.1.1 Physicochemical
parameters 42
4.1.3 Prawn 49
4.1.4 Crab 58
4.1.5 Mussels 70
4.1.6 Snail (Periwinkle and Apple Snail) 73
4.2 Discussion 80
CHAPTER 5 CONCLUSION
AND RECOMMENDATION
5.1 Conclusion
88
5.2 Recommendation
88
References
Appendix
LIST OF TABLES
2.1: Projected human
population, fish demand and supply (2000 – 2015) 5
2.2: Concentrations of
EPA and DHA 19
2.3 Types
of Sterols in Shellfish (milligram/100 grams shellfish) 21
4.1. Monthly Distribution Physicochemical Parameter of Akor River
44
4.2 Monthly
Distribution Physicochemical Parameter of Ihie river 45
4.3 Physicochemical
Parameter of Akor River 48
4.4 Physicochemical
Parameter of Ihie River 48
4.5 Morphometric
Parameter of the Prawns from Akor River in the Month 51
4.6 Morphometric
Parameter of Prawns from Akor River 51
4.7 Morphometric
Parameters of Female Prawns 53
4.8 Morphometric
Parameter of Male Prawns 54
4.9 Morphometric
Parameter of Crabs at the Two Sites in the Different Months 59
4.10 Morphometric Parameter of Crabs at the Two Sites in the
Different Stations 60
4.11 Morphological Parameter of Crabs Sexes and Species 66
4.12
Morphometric Parameters Crabs
Caught From Ihie River. 66
4.13
Morphometric Parameters Crabs
Caught From Akor River. 68
4.14 Morphometric Parameter
of Mussels at Different Stations and Months at Akor River. 71
4.15 Morphometric Parameter
of the species of Mussels 71
4.16 Species of Periwinkle Obtained In the Different Months 74
4. 17 Morphometric Parameter of periwinkle from Akor River 74
4.18: Pila ovata Obtained
at different stations From Different Sites of the Akor River 74
4.19 Physicochemical Analyses of the Two Water Bodies 78
LIST OF FIGURES
1 Fatty acid composition 16
2 Percentage calories from fat 17
3 Akor River Map 35
4 Ihie River Map 36
5 Comparative Analysis of Fresh Water
Prawn Male and Female Body Morphology 57
6 Comparative Analysis of Crabs Caught
From the Different Rivers 69
LIST OF PLATES
1: Lateral view of Macrobranchium
volenhoveni from Akor River 56
2: Lateral View of Macrobranchium
macrobtanchion Caught from Akor River 56
3: Dorsal View of Sudanonautes floweri 63
4: Sudanonautes floweri ventral
view 63
5: Louisea edeaensis
dorsal view 63
6: Louisea edeaensis
ventral view 63
7: Potamonautes ecorssei
dorsal view 63
8: Potamonautes ecorssei
ventral view 63
9: Potamonautes mhlophe dorsal view 64
10: Potamonautes mhlophe ventral
view 64
11: Potamonautes lovenii dorsal view 64
12: Potamonautes lovenii ventral view 64
13: .Dorsal view of Apatheria dahomeyensis caught from Akor River 72
14: Dorsal view of Magaritifera magaritifera caught form
Akor River 72
15: Side view of Magaritifera
falcata from Akor River 72
16: Melanoides fuscata from Akor River 75
17: Tympanotonus fasciolatus
from Akor River 75
18: Melanoides masculata
from Akor River 75
19: Ventral view of Pila ovata
from Akor River 75
20: dorsal view of Pila ovata from Akor River 75
CHAPTER 1
INTRODUCTION
1.5
BACKGROUND
OF THE STUDY
Exoskeleton-bearing
aquatic invertebrates consumed by man are known as shell fish. They include
different species of crustaceans, mussels and other echinoderms. They are found
in fresh water, estuarine and marine aquatic environment. They make up the
major classes of the phylum arthropoda and mollusca. Such shellfishes include
squids, octopus and cuttlefish which are cephalopods, clams, oysters also are
bivalves etc.
Shellfish have
been seen to be greatly important in the commercial industry of Nigeria.
Exploitation of water territories have been on the increase since there is an
increasing demand for protein foods as regards to health issues (Bankole,
2007). The stock of shell fish in the nation has also greatly reduced even in
the coastal regions and this may also be due to
environmental degradation which is highly detrimental to the lifecycle of
shellfish and their abundance (Nwosu, 2007). Poor fishing methods such as use
of poisons and other chemicals to harvest shellfish have also contributed to
the reduction and loss of species of shellfish (Deekae and Abowei, 2010).
Due to a growing
population, the quest for an increased production of shell fish is becoming of
more importance in fisheries. Inability to understand species distribution,
richness or abundance and the effect of physico-chemical factors is very
crucial in understanding any kind of resources management of shellfish.
The seasonal
production of shellfish has continued to provide the bulk of food for semi-urban
consumption and has also immensely contributed to the export market by
providing the bulk of shellfish to processing plants in those other countries.
Biodiversity was defined by United Nations as the variability among
living organisms from sources including inter alia, terrestrial, marine and
other aquatic ecosystem and ecological complexes of which they are part with
diversity within species, between species and ecosystem inclusive.
Species diversity
or abundance or richness is invariably known as biodiversity although most
biologists often refer to it as the totality of genes, species and ecosystem of
a particular region. The merit of the above definition is that it seems to
cover most circumstance and also unify all the traditional and variable vies
which were formerly identified.
1.6
STATEMENT
OF PROBLEM
Shell fish is a staple
product in Abia state but anthropogenic activities have decimated the
distribution and abundance of different shellfish, example the fresh water
shrimps, crabs and periwinkles. There are no records of prevalence and
abundance of shellfish in major fishing water bodies such as Ihie river and Akor
river, this is a major problem to conservation of shellfish and management.
1.7
JUSTIFICATION
There are many
rivers, lakes, streams and ponds in the South Eastern Nigeria yet with little
or no knowledge of shellfish. There is a need firstly for assessment of
shellfish stock in the natural habitat which would in turn enhance profitable exploitation and
production of these species at the long run.
1.8
OBJECTIVE
OF THE STUDY
The main objective
of this study is to study the distribution and abundance of shellfish and
physicochemical analysis of their aquatic habitat.
Specific objectives
in the selected stream include;
Ø to
study the biodiversity of the freshwater shellfish
Ø to
study the abundance of shellfish in the different rivers
Ø to
determine the physicochemical parameters of the water bodies
Ø to
compare the shellfish abundance and distribution between the water bodies
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