ABSTRACT
The food and feeding habits of the Africa catfish, Claries gariepinus in River Esin Ufot were studied from samples caught in each month during October 2016 to September, 2017. Analysis of the stomach content (n = 340) showed that the fish ingests a variety of items of plant origin, animal origin, detritus and sand grains. The items that comprises the plant origin were algae and macrophytes whereas those of animal origin and crustacean, insects, fish, mollusks, nematodes and fish eggs. The insects ingested by the fish were most diverse as they were developmental belonging to several taxa such as Hemiptera, Diptera and Odonata. Oreochromis niloticus, was the only fish species ingested by Clarias gariepinus in the study. There were differences in the relative importance of the various items ingested by the fish. Thus, the frequency of occurrence of insects was the highest (80.8%), and this was followed by macrophytes (6.04%)and zooplankton (59.2%), fish (26.4%) and fish eggs (14.0%). Numerically the most important food were crustacean (90.8%) followed by insects (5.31%), mollusks (0.85%) and O. niloticus (0.82%). Based on the results from frequency of occurrence and numerical abundance, crustacean zooplankton, insects and fish are considered as the major food of the studied C. gariepinus. The items of plant origin, detritus and sand grains were believed to be accidentally ingested while the fish was pursuing its prey. This shows that C. gariepinus in River Esin Ufot is considered to have a carnivorous feeding habit. The study also found size-based and seasonal differences in the relative importance of the major food items. The frequency shows that the fish feeds progressively less on zooplantation and insects, but more of O.niloticus as it grows larger. In addition, it feeds relatively more on O.niloticus than any other major items in March through August. This is attributed to increased abundance of prey following intensive breeding in the rainy seasons (February–April and July–September). High frequencies of C gariepinus with empty stomach were recorded during the rainy seasons in which time the fish breeds intensively. This shows that at this time the fish could be engaged more in spawning than in feeding activity.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables x
List of Figures xi
Abstract xii
CHAPTER ONE: INTRODUCTION
1.1 Fish
(Clarias gariepinus): Source of Food
for Man 1
1.2 Statement
of the Problem 3
1.3 Justification
of the Study 4
1.4 Aim and
Objectives of the Study 4
CHAPTER
TWO: LITERATURE REVIEW
2.1 African
Catfish (Clarias gariepinus Burchell,
1822) 5
2.1.1 Description 7
2.1.2 Habits 8
2.1.3 Natural spawning 8
2.1.4 Rearing
8
2.1.5 Hybridization 9
2.2 Taxonomy of African Catfish (Clarias gariepinus) 9
2.3 Infraclass
– Teleostei 10
2.4 Digestive
Tract, Food and Habits 10
2.5 Definition
of the Gut and its subdivisions 11
2.6 The
Oro-pharyngeal Cavity 12
2.7 Microscopic
Morphology 13
2.7.1. Oesophagus 14
2.7.2 Stomach 16
2.7.3 Intestine 20
2.7.4 Rectum 21
2.7.5 Pyloric
caeca 22
2.7.6 Ultrastructural
observations 23
2.7.7 Innervations 26
2.7.8 Digestive
enzymes 28
2.7.9 Blood
supply to the digestive tract 31
2.7.10. Gut motility 32
2.7.11 Ontogenetic
development of teleost digestive system 33
CHAPTER THREE: MATERIALS AND METHOD
3.1
Study Area 35
3.2 Collection
of Samples 37
3.3 Biometric
Data 37
3.4 Stomach
Content Examination 38
3.5 Numerical
Method 38
3.6 Frequency
of Occurrence Method 38
3.7 Investigation
of Size Based and Seasonal Differences in Food Habit. 39
CHAPTER FOUR: RESULTS
4.1
Period/time of Fish Collection/Harvesting 40
4.2 Percentage
of Fish with Empty Stomach during both Seasons 41
4.2.1 Sexual
dimorphism 42
4.3 Relative
Importance of Food Items Found in the Stomach of C. gariepinus 43
4.4 Relationship
between the Length of C. gariepinus
and Frequency
of Occurrence of its Major Food Item 44
4.5 Seasonal
fluctuation of food items in the stomach of C.
gariepinus. 45
4.5.1 Seasonal
fluctuation in the numerical abundance of the food item 46
4.6 Monthly
Distribution of Fish (O. niloticus) 48
4.7
Monthly frequency of C. gariepinus
with empty stomach 49
CHAPTER FIVE
Discussion 50
References 55
Appendices 89
LIST OF TABLES
1 Fishes caught during the sampling
year 40
2 Relative importance of items
observed in stomach content samples (n=340) of
Clarias
gariepinus
from River Esin Ufot, Akwa Ibom 43
LIST OF FIGURES
1 Map
of Oron showing study area
36
2
Seasonal variation in
percentage of C. gariepinus from
Esin Ufot River with empty stomachs 41
3
Sexual dimorphism in
percentage of C. gariepinus from
River
Esin Ufot with empty stomach. 42
4 Relationship
between the length of Clarias gariepinus
from River Esin Ufot and the frequency of occurrence
of its
major food items 44
5 Seasonal fluctuation in
the frequency of occurrence of major
food
items of C. gariepinus from River
Esin Ufot. 45
6 Seasonal fluctuation in
the numerical abundance of (a)
zooplankton,
(b) insects and (c) fish, Oreochromis
niloticus in
the
stomach of Clarias gariepinus from
River Esin Ufot 47
7
Monthly distribution
of fish (O. niloticus), from the
annual
total, ingested by Clarias gariepinus in River Esin Ufot 48
8 Monthly frequency of Clariasgariepinus with empty
stomach
from River Esin Ufot 49
CHAPTER
1
INTRODUCTION
1.1 BACKGROUND
OF THE STUDY
Fish
(Clarias gariepinus): Source of Food
for Man
Food is one of the basic needs of man
(Pierce, 2010). Food is produced through agriculture which is the cultivation
of plants and rearing of animals for man’s consumption. Since agriculture
produces the food that provides the calories and nutrients essential for health
and productive life, it is interlinked in many important ways to nutrition and
health (Michael, 2011). Nutrients here include carbohydrates, proteins, fats
and oil, minerals, vitamins and water. Of these nutrients, for growth and
repair of damaged tissues, it is the proteins that supply the body with amino
acids necessary for plants and animals are the main source of protein although
the animal sources are preferred because of the presence of essential amino acids
and higher digestibility. The animal protein sources include fish, poultry,
dairy, pork, snail and rabbit etc. Fishing, like other hunting activities has been
a major source of food for the human race and has put an end to the unsavory
outbreak of anaemia and kwashiorkor in developing countries. It accounted for
half of the world total supply of animal protein (FAO, 1991; Olagunju et al., 2007). In Nigeria, fisheries
play a very important role in the agricultural sector of the economy (Kudi et al., 2008). Its contribution to Gross
Domestic Product (GDP) rose from 76.76 billion in2001 to N162.61 billion in
2005 (CBN, 2005). In Nigeria, fish is an important source of protein. It
provides 40% of the dietary intake of animal protein of the average Nigerian
(FDF, 1997; Sogbesan et al., 2006).
According to Adekoya and Miller (2004), fish and fish products accounted for
more than 60 % of the total protein consumed by adults especially in Nigerian local
cities.
Amiengheme (2005) listed the
importance of fish and fish products to Human
Nutrition as follows:
i.
Fish food accounts for
higher nutrient greater to all terrestrial meats (beef, pork and chicken;
ii. Fish
is an excellent source of high quality animal protein and highly digestible
energy;
iii. Fish
also supplies sulphur and essential amino acids such as lysine, leucine, valine
and arginine. It is therefore suitable for supplementing diets of high carbohydrate
contents;
iv. Fish
is also a good source of thiamine as well as an extremely rich source of
(Omega–3) polysaturated fatty acids, fat soluble vitamins (A, D and E), water
soluble vitamins (B complex) and minerals (calcium, phosphorus, iron, iodine
and selenium).It has a high content of polysaturated (Omega III) fatty acids,
which are important in lowering blood cholesterol level and high blood
pressure. It reduces the risk of sudden death from heart attacks and reduces
rheumatoid arthritis. It also lowers the risk of age- related muscular degeneration
and vision impairment; decreases the risk of bowel cancer and reduces insulin
resistance in skeletal muscles.
Nigerians are large consumers of
fish, with an annual average demand estimate at 1.4 millionmetric tonnes (Kudi et al., 2008). However a demand and
supply gap of at least 0.7 millionmetric tonnes exists nationally with import
making up for the short fall at a cost of 400 billion United States Dollars per
year. Domestic fish production of about 0.5 million metric tonnes is supplied
by artisan fishermen (85%), and fish farmers (15 %) (Adekoya and Miller, 2004;
Emokaro et al. 2010). According to
FAO (2000), this figure (0.7 million metric tonnes) makes Nigeria the largest
importer of fish in the developing world. To take advantage of the large market
created by this deficit, some Nigerians are increasing their participation in
aquaculture, with many fish farmers focusing on African catfish, Clarias gariepinus,
as they have been shown to have a potential market value of two to three times that
of other cultivable species like Tilapia and Heterobranchus (FAO, 2000; Fafioye and Oluajo, 2005; Emokaro et al., 2010). Fish farming generates
employment directly and indirectly for people involved in the value addition of
processing (Olagunju et al., 2007).
Aquaculture is also a ready alternative to wild fish supply because of great
concern on fish depletion in the oceans due to over fishing; fish deaths caused
by oil spillage and heavy metal pollution; natural disasters like Tsunami,
flooding and excessive drought due to climate change (Dublin-Green et al., 1998; UNEP, 2004; Damassa, 2006;
Gabriel et al., 2007; Tawari-Fufeyin et al., 2008). A survey by Addo (2005),
revealed that Nigerian children below the age of 18 years, who make up about 47
% of our total population are still victims of stunting, wasting and
under-weight. So with the increased establishment of aquaculture in Nigeria, it
is possible to reverse this trend of malnourishment among Nigerians below the age
of eighteen years.
1.2
STATEMENT OF THE PROBLEM
Despite the increasing interest and
aquaculture in Nigeria, there is no paucity of knowledge on the basic biology
of the digestive tract and feeding habits of farmed and harvested African
catfish.
1.3 JUSTIFICATION OF THE STUDY
This study of food and feeding habits
of water fresh fish species is a subject of continuous research because it
constitutes the basis for the development of a successful fisheries management
program for capture and culture fishery. Thus in an attempt to fill this knowledge
gap, a study was conducted on various aspects the biology of C. gariepinus in Esin Ufot River, Oron,
Akwa Ibom State, Nigeria and the length-weight relationship, sex ratio,
maturity and condition factor of the fish have been published earlier (Lemma et al., 2014). Also studies on stomach
contents could provide useful information with regards to positioning of fishes
in food web in their environment and in formulating management strategy option
in multispecies fishery (Adeyemi et al.,
2009).
1.4 AIM AND OBJECTIVES OF THE STUDY
Aim
To study the food and feeding habits
of C. gariepinus in River Esin Ufot,
Oron, Akwa Ibom State to contribute to the existing knowledge of the biology of
the fish and also to provide information on the diets, nourishment and
abundance of natural food needed by fish.
Other
objectives are;
·
to find their size-based
and seasonal differences in the relative importance of their food,
·
to estimate their
relatively important food items, and
·
to quantitatively
describe the dietary characteristics of
Clarias gariepinus.
Click “DOWNLOAD NOW” below to get the complete Projects
FOR QUICK HELP CHAT WITH US NOW!
+(234) 0814 780 1594
Login To Comment