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American Journal of Biology and Life Sciences
2014; 2(5): 122-134
Published online November 10, 2014 (http://www.openscienceonline.com/journal/ajbls)
Studies on the food composition and feeding
pattern of fish communities in Qua Iboe River,
Niger Delta region of Nigeria
Imaobong Emmanuel Ekpo
*
, Ofonmbuk Ime Obot, Mandu Asikpo Essien-Ibok
Department of Fisheries & Aquatic Environmental Management, University of Uyo, P.M.B. 1017, Uyo - 520001, Nigeria
Email address
imaobongekpo14@yahoo.com (I. E. Ekpo)
To cite this article
Imaobong Emmanuel Ekpo, Ofonmbuk Ime Obot, Mandu Asikpo Essien-Ibok. Studies on the Food Composition and Feeding Pattern of
Fish Communities in Qua Iboe River, Niger Delta Region of Nigeria. American Journal of Biology and Life Sciences.
Vol. 2, No. 5, 2014, pp. 122-134.
Abstract
Trends in the diets and feeding activity of 21 families of fish comprising 37 species, 29 genera and 543 individuals from two
ecologically distinct zones of Qua Iboe River were investigated from July – October 2008. The Relative Frequency,
Percentage Point and Index of Food Dominance methods were used to determine their diets and feeding patterns. The
proportion of fish with food were higher (339; 62.43%) than those without food (204; 37.57%) but were statistically not
significant (P>0.05). Of the 356 specimens examined in Station 1, 198 (55.62%) had food while 158 (44.38%) were without
food. Out of the 187 specimens in Station 2, 141 (75.40%) had food while 46 (24.60%) were without food. In all, 204
specimens (37.57%) had empty stomachs, 79 (14.55%) had full stomachs whereas 63 (11.60%), 89 (16.39%) and 82
(15.10%) were for ¾, ½ and ¼ respectively. The six specimens of P. africana had empty stomach. Among the fish species
represented by single specimen, only A. fasciatus had empty stomach. Two of the remaining five species: E. aeneus and S.
barracuda had fully distended stomachs while T. goreensis and X. nigri had their stomachs half full. The remaining two
species, P. peroteti and T. guineensis) had three quarter full and one quarter full stomachs respectively. A total of thirteen
major food items were identified: nine in Station 1 and twelve in Station 2. In Station 1, the dominant food item was
sediments (75.16%) and the least was amphibians (5.10%). Fish and sediments were the dominant food items (15.63%)
while unidentified food was the least (1.56%) in Station 2. However, high values of unidentified foods and in more species
were recorded in Station 1 than Station 2. The food of these species were diversified containing both plant, animal and non-
living materials.
Keywords
Stomach Contents, Food Habit, Feeding Intensity, Fish Communities, Nigeria
1. Introduction
Water is essential for all known forms of life, and is
approximated to cover 70.9% of the earth surface [1, 2, 3, 4
and 5]. Fish is regarded as the cheapest source of protein
among the urban and rural populace. The demand for fish as
a source of protein increases as the human population grows
[6]. Nutritionally, fish consumption is widely encouraged due
to its high content of omega-3 polyunsaturated fatty acids
and protein [7].
Since organisms do not live in isolation in any ecosystem
but interact with one another through the food-web
relationship [8], the feeding relationship of organisms of high
trophic levels of the fish has become necessary to
complement the series of ecological studies. Moreover, [9]
postulated that the availability of the food of the fish species
can also influence their distribution. The knowledge of food
and feeding pattern of fish according to [8] is a prerequisite
to the improvement and management of commercially
important fish species.
Qua Iboe river is a major river that flows through the
urban and rural villages and towns in Akwa Ibom State. Sited
123 Imaobong Emmanuel Ekpo et al.: Studies on the Food Composition and Feeding Pattern of Fish Communities in Qua Iboe River,
Niger Delta Region of Nigeria
at its estuarine zone is the popular oil producing Exxon
Mobil at Ibeno, Eket Local Government Area. As a result of
its location, it has attracted both national and international
bodies, ecologists and other environmentalists over the years.
Several publications are available on the Qua Iboe River and
its estuary on food and feeding habits of single species of fish
[10, 11, 12, 13, 14, 15], among others. But there is dearth of
data on its multispecies’ food and feeding habits. This study,
therefore, focuses on the food and feeding patterns of the
multispecies communities of the freshwater and estuarine
zones in the river in order to bridge the gap on the above
information.
2. Materials and Methods
2.1. Study Area
Fig. 1. Maps of the sampling stations: (A) Nigeria showing the location of Qua Iboe River in Akwa Ibom State (B) Qua Iboe River showing sampling stations 1
& 2 [19].
Qua Iboe River system (7
o
30׳ – 8
o
20׳W; 4
o
30׳ – 5
o
30׳N)
is one of the three major hydrographic features in Akwa Ibom
State, Nigeria [16] (Fig. 1). The study area was divided into
two main zones: Station 1 is the freshwater zone while
Station 2 is the estuarine zone. It is located in the rain forest
belt. In spite of its present status as the capital of Akwa Ibom
State, the city is still dotted with palm trees, banana, plantain
and fruit trees with poor drainage. The area has warm humid
climate condition but high temperature and heavy rains
distributed almost all year round. The maximum temperature
is between 26-28
ᴼ
C and mean annual rainfall is 362.5mm.
The climate presents two distinct seasons; a rainy season
(April - October) and a dry season, (November - March) [17,
18].
2.2. Fish Sampling
Several fishing methods were used in a standardized
manner to collect the maximum number of species and
individuals in different sizes including gill nets (with
stretched mesh size of 10–30mm), hooks and lines, and traps
(which were set overnight prior to the sampling day). The
unbaited gill nets and baited traps (using baits such as
earthworms, fish and palm fruits) were set mainly at the
vegetated marginal regions while hooks and lines (baited)
were used both in vegetated areas and in the open water.
American Journal of Biology and Life Sciences 2014; 2(5): 122-134 124
Fish samples collected were preserved in 10%
formaldehyde solution in well-labeled containers to reduce
microbial digestion to the minimum [20, 21] and taken to the
laboratory for identification with the aid of identification
keys [22, 23, 24].
2.3. Statistical Analysis
The number of items ingested by an individual fish was
considered as food richness. Several indices have been
employed in expressing quantitative importance of different
food items in fish diet [25, 26, 27, 28, 29, 10 and 30]. In this
work, the indices used were: Frequency of occurrence of
each food item was obtained by expressing the number of
stomach each food item occurred as percentage of total
number of stomach. The frequencies of the variety of items in
the stomachs were noted and these data were used to evaluate
their Relative Frequency (RF) by expressing the frequency of
each as a percentage of the sum of all the frequencies of all
the food items, all RF values sum up to 100%. The mean
total points gained by each food item was computed and
expressed as percentage of the grand total points (PP) gained
by all stomach contents. The integrated importance of each
food item, Index of Food Dominance (IFD) was then
calculated as it incorporates the RF and PP, expressing them
as percentages.
3. Results
3.1. Fish Species
Table 1. Fish species sampled showing stomachs with and without food in Qua Iboe River, Nigeria.
Fish species Station 1 Station 2
WF WOF WF WOF
Anaspidoglanis akiri (Rich, 1987) 6 1
A. fasciatus (Geoffery St. Hilarire, 1827) - 1 - -
Bathygobius soporator (Valenciennes) - - 1 1
Barbus callipterus (Boulenger, 1907) 34 91 - -
Brienomyrus brachyistus (Gill, 1863) 44 1 - -
Brycinus longipinnis (Gunther, 1864) 14 6 - -
Chromidotilapia guntheri (Sauvage, 1882) 11 7 - -
Chrysichthys aluuensis (Risch, 1985) 3 4 - -
C. nigrodigitatus (Lacepede, 1803) - - 3 2
Ctenopoma nebulosum (Gunther, 1896) 1 2 - -
Epinephelus aeneus - - 1 -
Epiplatys bifasciatus (Steindachner, 1881) 8 1 - -
E. sexfasciatus (Gill, 1882) 10 11 - -
Erpetoichthys calabaricus (Smith, 1866) 21 3 - -
Ethmalosa fimbriata (Bowdich, 1825) - - 12 3
Hemichromis fasciatus (Peters, 1857) 4 8 - -
Isichthys henrgii (Gill, 1863) 3 1 - -
Liza dumerili - - 21 -
L. falcipinnis (Valenciennes, 1836) - - 31 -
L. grandisquamis (Valenciennes, 1836) - - 45 7
Malapterurus electricus (Gmelin, 1789) 21 9 - -
Mugil cephalus (Linnaeus, 1758) - - 2 3
Parachanna africana (Steindachner, 1897) - 6 - -
Pelvicachromis pulcher (Boulenger, 1901) 4 - - -
Pomadasys peroteti (Cuvier, 1830) - - 1 -
P. jubelini (Cuvier, 1830) - - 4 3
Pseudotolithus elongatus (Bowdich, 1825) - - 13 4
Polydactylus quadrifilis (Cuvier, 1829) - - 1 1
Polycentropsis abbreviata (Boulenger, 1901) 2 - - -
Sarotherodon melanotheron (Ruppell) - - 2 -
Sphyraena afra (Peters, 1844) - - 1 -
Thysochromis ansorgii (Boulenger, 1911) 1 5 - -
Tilapia guineensis (Bleeker, 1862) - - 1 -
T. mariae (Boulenger, 1899) 10 2 - -
Trachinotus goreensis (Cuvier, 1832) - - 1 -
T. teraia (Cuvier, 1832) - - 1 22
Xenomystus nigri (Gunther, 1868) 1 - - -
Grand Total 198 158 141 46
WF = Stomachs with food, WOF = Stomachs without food
125 Imaobong Emmanuel Ekpo et al.: Studies on the Food Composition and Feeding Pattern of Fish Communities in Qua Iboe River,
Niger Delta Region of Nigeria
In all, 543 specimens of fish belonging to 21 families, 29
genera and 37 species were examined in relation to their diets.
A total of 37 species of fish were sampled: Station 1 had
twenty species while Station 2 had seventeen species. The
sample size ranged between one specimen in seven species
(A. fasciatus, E. aeneus, P. peroteti, S. barracuda, T.
guineensis, T. goreensis and X. nigri) and 125 specimens in B.
callipterus. The total length varied from 2.60 cm (E.
bifasciatus, E. sexfasciatus and H. fasciatus) to 35.10 cm (E.
calabaricus).
The results of the food analysis showed that proportion of
fish with food were higher (339; 62.43%) than those without
food (204; 37.57%) but were statistically not significant
(P>0.05) as depicted in Table 1. Of the 356 specimens
examined in Station 1, 198 (55.62%) had food while 158
(44.38%) were without food. Out of the 187 specimens in
Station 2, 141 (75.40%) had food while 46 (24.60%) were
without food.
3.2. Feeding Intensity
The stomach fullness method shown in Table 2 revealed
that of the 543 specimens examined, 204 (37.57%) had
empty stomachs, 79 (14.55%) had full stomachs whereas the
partially full: 63 (11.60%), 89 (16.39%) and 82 (15.10%)
were for ¾, ½ and ¼ respectively. Among the fish species
represented by single specimen, only A. fasciatus had empty
stomach. Two of the remaining five species: E. aeneus and S.
barracuda had fully distended stomachs while T. goreensis
and X. nigri had their stomachs half full. The remaining two
species, P. peroteti and T. guineensis) had three quarter full
and one quarter full stomachs respectively. The six specimens
of P. africana had empty stomachs. Thus, the result implied
that percentage of stomachs with food was higher than those
without food.
Table 2. Degree of stomach fullness illustrating feeding intensity among fish species in Qua Iboe River, Nigeria.
Fish species N
Total length (TL,
cm)
Stomach fullness
Station 1 Station 2
Min Max 4/4 3/4 1/2 1/4 0 4/4 3/4 1/2 1/4 0
A.akiri 7 6.50 10.00 1 1 3 1 1
A. fasciatus 1 10.00 1
B. soporator 2 8.00 10.90 1 1
B. callipterus 125 4.60 8.00 4 2 21 7 91
B. brachyistus 45 3.60 11.70 8 19 5 12 1
B. longipinnis 20 7.50 9.80 2 1 8 3 6
C. guntheri 18 3.70 11.40 2 4 5 7
C. aluuensis 7 6.00 7.70 2 1 4
C. nigrodigitatus 5 19.70 27.80 2 1 2
C. nebulosum 3 6.90 13.30 1 2
E. aeneus 1 15.20 1
E. bifasciatus 9 2.60 3.60 1 4 3 1
E. sexfasciatus 21 2.60 6.10 1 2 4 3 11
E. calabaricus 24 27.72 35.10 10 1 7 3 3
E. fimbriata 15 13.20 17.80 2 2 8 3
H. fasciatus 12 2.60 9.10 2 1 1 8
I. henrgii 3 4.70 11.10 1 2
L. dumerili 21 10.10 23.50 8 5 2 6
L. falcipinnis 31 8.50 20.00 15 3 10 3
L. grandisquamis 52 10.90 23.7 12 10 15 8 7
M. electricus 30 7.70 19.30 3 1 10 7 9
M. curema 5 10.90 16.80 1 1 3
P. africana 6 7.50 20.60 6
P. pulcher 4 6.60 10.20 1 1 2
P. peroteti 1 8.40 1
P. jubelini 7 11.80 15.10 1 2 1 3
P. elongatus 17 11.40 21.50 3 1 7 2 4
P. quadrifilis 2 20.00 20.60 1 1
P. abbreviata 2 3.90 8.00 2
S. melanotheron 2 10.70 18.5 1 1
S. barracuda 1 23.20 1
Th. ansorgii 6 3.10 10.30 1 5
T. guineensis 1 14.20 1
T. mariae 12 7.00 11.70 2 5 3 2
T. goreensis 1 9.80 1
T. teraia 23 6.20 9.50 1 22
X. nigri 1 16.2 1
Grand total 543 79 63 89 82 204
American Journal of Biology and Life Sciences 2014; 2(5): 122-134 126
3.3. Food Richness
Fig. 2. Relative frequency of food items found in the guts of fish in Qua Iboe
River, Nigeria.
A total of thirteen major food items (algae, Amphibia,
Annelida, Crustacea, detritus, fish, Insecta, Mollusca,
Nemata, plant materials, Protozoa, sediments and
unidentified foods) were found in the stomachs of the fish.
Of these, nine were recorded in STN 1 while STN 2 had
twelve food items (Fig. 2). In STN 1, the dominant food item
was sediments (75.16%) and the least amphibians (5.10%).
Fish and sediments were the dominant food items (15.63%)
while unidentified food was the least (1.56%) in STN 2.
Amphibia was the only food item not found in STN 2 while
in STN 1, four major items (Annelida, Insecta, Mollusca and
Protozoa) occurring in STN 2 were absent.
3.4. Food Composition
The results of the gut contents analysis were carried out
based on all the species encountered, with the exception of P.
africana and A. fasciatus in which the six and one specimens
caught had empty stomachs respectively (Tables 1 and 2).
The tables showing the food items of the fish species were
arranged according to stations: Tables 3 – 6 constituted those
of Station 1 while Tables 8 – 11 were for Station 2. Table 7
was made up of the food items of three and one fish species
of Stations 1 and 2 respectively.
Table 3. Analysis of stomach contents of E. calabaricus, B. brachyistus, I. henrgii and X. nigri by (%RF), Point Percentage (%PP) and Index of Food
Dominance (%IFD) methods in Station 1 in Qua Iboe River, Nigeria.
Food items
B. brachyistus E. calabaricus I. henrgii X. nigri
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 7.07 4.54 3.38 6.06 2.57 1.24 6.67 5.13 3.34
Chlorophyta 5.46 4.48 3.08
Myxophyta 8.04 8.45 5.47 3.03 1.47 0.71 13.33 5.13 6.67
Plant materials
Leaf fragments 5.15 5.26 5.27 4.04 4.41 2.82 13.33 7.69 9.99
Root 1.01 1.10 0.18
Seeds 2.25 2.31 1.01 2.02 1.47 0.47
Insecta
Insect wing 2.25 3.82 1.67
Chironomid larvae 5.79 7.33 8.25 2.02 1.10 0.35 6.67 5.13 3.34
Trichopteran pupae 1.61 1.59 0.50 4.04 2.57 1.65
Insect remains 8.04 10.35 16.18 11.11 11.03 19.42 6.67 5.13 3.34 20.0 12.5 13.07
Coleopteran 1.61 1.12 0.35
Crustacea
Penaeid shrimp 2.25 2.07 0.91
Macrobranchium sp 3.03 4.04 0.88
Ostracods 4.18 3.82 3.11 2.02 2.21 0.71
Cyclops 3.86 3.50 2.63
Daphnia 5.47 5.73 6.10
Amphibia
Tadpoles 1.01 3.68 0.59
Nemata 6.11 6.53 7.76 6.67 7.69 9.00
Fish
Scales 3.86 2.31 1.74 2.02 0.55 0.18 6.67 7.69 9.00
Fish remains 6.67 10.26 6.67
Detritus
FPOM 6.75 5.97 7.84 12.12 8.46 16.25 6.67 7.69 9.00 20.0 6.25 12.50
CPOM 8.04 9.40 14.70 7.17 5.15 5.77 6.67 17.95 11.67 20.0 18.75 18.75
Sediments
Mud 2.57 2.15 1.08 5.05 3.68 2.94
Sand grains 7.72 6.29 9.45 11.11 6.07 10.69 20.0 18.75 18.75
Unidentified foods 1.93 3.03 1.14 13.13 16.91 35.18 20.0 20.51 39.99 20.0 43.75 43.75
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
127 Imaobong Emmanuel Ekpo et al.: Studies on the Food Composition and Feeding Pattern of Fish Communities in Qua Iboe River,
Niger Delta Region of Nigeria
Table 4. Analysis of stomach contents of A. akiri, C. aluuensis and M. electricus by %RF, %PP and methods in Station 1 in Qua Iboe River, Nigeria.
Food items
A. akiri C. aluuensis M. electricus
Percentages
RF PP IFD RF PP IFD RF PP IFD
Plant materials
Leaf fragments 2.90 2.40 0.75
Roots 4.35 3.85 1.81
Palm fruit remains 50.0 69.81 81.45
Fish
Eggs 28.57 20.76 13.84
Scales 18.18 33.33 30.30
Flesh 18.18 26.67 24.25
Insecta
Dipteran larvae 11.59 6.73 8.45
Trichopteran larvae 11.59 6.73 8.45
Crustacea
Shrimp 27.27 26.67 36.37 8.70 18.75 17.66
Copepods 5.80 21.64 13.59
Nemata 5.80 4.33 2.72
Detritus
FPOM 9.09 2.22 1.01 8.70 2.40 2.26
CPOM 9.09 4.44 2.02 15.94 12.02 20.75
Sediments
Sand grains 21.43 9.43 4.72 18.18 6.67 6.06 8.70 3.13 2.95
Stone 1.45 5.77 0.91
Unidentified foods 14.49 12.56 19.71
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
Table 5. Analysis of stomach contents of C. guntheri, H. fasciatus, T. mariae and Th. ansorgii by %RF, %PP and %IFD methods in Station 1 in Qua Iboe River,
Nigeria.
Food items
C. guntheri H. fasciatus T. mariae Th. ansorgii
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 6.00 3.13 2.40 3.33 2.35 0.50 20.0 16.65 16.67
Chlorophyta 4.00 9.38 7.18 11.11 6.90 4.17 3.33 2.35 0.50
Myxophyta 4.00 5.21 2.66 20.0 11.11 11.11
Plant materials
Leaf fragments 2.00 1.04 0.27 20.00 30.59 38.91
Insecta
Insect remains 4.00 7.29 3.72 11.11 10.35 6.27
Crustacea
Cyclops 6.00 7.29 5.58
Daphnia 14.00 9.89 10.63 20.0 50.0 50.0
Fish
Eggs 3.33 1.18 0.25
Scales 14.00 13.02 23.25 11.11 17.24 10.42 13.33 12.94 10.97
Flesh 22.22 41.38 50.0
Detritus
FPOM 8.00 13.51 13.78 6.67 3.53 1.50 20.0 5.56 5.56
CPOM 4.00 8.33 4.25 22.22 17.24 20.83 10.00 7.06 4.49 20.0 16.67 16.67
Sediments
Mud 13.33 7.06 5.99
Sand grains 12.00 12.50 19.13 22.22 6.90 8.34 20.00 27.06 34.42
Unidentified foods 6.00 9.38 7.18 6.67 5.88 2.47
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
American Journal of Biology and Life Sciences 2014; 2(5): 122-134 128
Table 6. Analysis of stomach contents of B. callipterus, B. longipinnis, C. nebulosum and P. abbreviata by %RF, %PP and %IFD methods in Station 1 in Qua
Iboe River, Nigeria.
Food items
B. callipterus B. longipinnis C. nebulosum P. abbreviata
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 10.0 3.53 1.43
Chlorophyta 10.0 12.12 9.39
Plant materials
Leaf fragments 24.64 30.06 40.96 10.0 7.58 7.55 14.29 10.35 8.58
Seeds 1.67 1.52 0.25
Insecta
Dipteran larvae 14.29 10.35 8.58
Wing ant 1.67 3.54 0.59
Insect remains 18.84 16.56 16.80 11.67 13.13 15.26
Coleopteran 14.29 10.35 8.58
Crustaceans
Crab remains 1.67 4.04 0.67
Penaeus sp 1.45 0.61 0.05
Ostracods 3.33 6.57 2.18
Cyclops 2.90 1.23 0.19
Daphnia 1.45 1.84 0.14
Fish
Bones 1.45 1.23 0.10
Scales 14.29 6.90 5.72
Fish remains 100 100 100 14.29 41.90 34.28
Detritus
FPOM 14.49 12.88 10.05 5.00 2.02 1.01
CPOM 17.39 14.72 12.17 10.00 8.08 8.05
Sediments
Sand grains 21.67 20.71 40.86 28.57 20.69 34.28
Unidentified foods 17.39 20.86 19.54 13.33 17.17 22.79
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
Table 7. Analysis of stomach contents of E. bifasciatus, E. sexfasciatus and P. pulcher in Station 1 and T. guineensis in Station 2 by %RF, %PP and %IFD
methods in Qua Iboe River, Nigeria.
Food items
E. bifasciatus E. sexfasciatus P. pulcher T. guineensis
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 40.0 13.32 60.60
Chlorophyta 10.57 7.90 4.66
Dinophyta 10 6.67 3.03
Myxophyta 20.0 26.67 12.13
Plant materials
Leaf fragments 10.0 33.33 15.16
Insecta
Insect wing 10.0 13.33 6.06
Chironomid larvae 5.26 2.63 0.77
Trichopteran larvae 46.67 72.22 89.94 29.17 48.67 67.25
Insect remains 13.33 5.56 1.90 4.17 3.54 0.70
Crustacea
Shrimp remains 8.33 15.04 5.93
Nemata 16.67 15.49 12.23
Fish
Scales 15.79 21.05 18.53
Detritus
FPOM 13.33 5.56 1.90 4.17 2.66 0.53 15.79 6.58 5.79
CPOM 20.0 9.26 4.94 20.83 9.29 9.17 21.05 21.05 24.70
Sediments
Mud 10.57 3.95 2.33
Sand grains 21.05 36.84 43.23 10.0 6.67 3.03
Unidentified foods 6.67 7.41 1.32 16.67 5.31 4.19
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
129 Imaobong Emmanuel Ekpo et al.: Studies on the Food Composition and Feeding Pattern of Fish Communities in Qua Iboe River,
Niger Delta Region of Nigeria
Table 8. Analysis of stomach contents of C. nigrodigitatus, E. fimbriata, S. barracuda and S. melanotherodon by %RF, %PP and %IFD methods in Station 2 in
Qua Iboe River, Nigeria.
Food items
C. nigrodigitatus E. fimbriata S. barracuda S. melanotherodon
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 49.60 47.11 57.04 36.36 25.0 23.63
Chlorophyta 4.13 2.89 2.54
Dinophyta 4.74 7.22 6.24
Myxophyta 9.09 8.33 5.26
Plant materials
Leaf fragments 11.11 4.65 3.77 22.22 6.67 6.67 18.18 33.33 42.10
Insecta
Dipteran larvae 2.48 3.47 1.83
Crustacea
Penaeid shrimp 33.33 34.88 39.64
Ostracods 1.65 1.78 0.61
Calanoids 9.91 14.38 11.48
Crab remains 11.11 27.91 22.65 14.87 22.01 4.07
Molluscs
Bivalve 22.22 9.30 15.09
Neritina sp 11.11 6.98 5.66
Nemata 9.09 16.67 10.53
Protozoans
Foraminifera 4.13 4.05 3.56
Tinitinnida 4.96 3.76 3.97
Fish
Fish remains 11.11 16.28 13.21 66.60 93.33 93.33
Detritus
FPOM 4.13 3.18 2.79 9.09 4.17 2.63
CPOM 3.31 2.31 1.63
Sediments
Sand grains 4.96 4.05 4.27 18.18 12.5 15.79
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
Majority of the fish species in STN 1 were mostly
predators (11 species; 61.11%) and the least (3 species;
16.67%) were herbivores. Nine (50.0%) species constituted
detritivores. Similar pattern also occurred in STN 2 but with
slight variation: the most abundant feeding habit was
predators (9 species; 52.94%) and the least (I species; 5.88%)
was herbivore. Algivore were made up of three species
(17.65%) and detritivores were observed in four species
(23.52%). Generally, most of the fishes were predators.
Table 3 showed significant %IFD of the food items
considered to be of primary importance in B. brachyistus to
be algae (11.92), insects (26.95), crustaceans (12.75), detritus
(22.54), sediments (10.53); in E. calabaricus, insect (21.42),
detritus (22.02) and sediments (13.63); in I. henrgii, algae
(10.01), fish (15.67) and detritus (20.67) and in X. nigri,
insects (13.07) and sediments (18.75).
Table 4 depicted the significant %IFD of food items
considered to be of primary importance in A. akiri to include
plants (81.45) and fish (13.84); in C. aluuensis, fish (54.55)
and crustaceans (36.37) and in M. electricus, detritus (23.01)
and crustaceans (31.25).
IFD (%) values of food items considered to be of primary
importance in Th. ansorgii, T. mariae, H. fasciatus and C.
guntheri were algae (27.78), crustaceans (50.00), detritus
(22.23); algae (38.91), fish (11.22), detritus (40.41); fish
(60.42) and detritus (20.83); and algae (12.24), crustaceans
(16.21), fish (23.25), detritus (18.06) and sediments (19.13)
respectively as illustrated in Table 5.
Table 6 showed the %IFD of food items considered as
primary importance in B. callipterus to be plants (40.96),
insects (16.80) and detritus (22.22); in B. longipinnis, algae
(10.82), insects (15.85) and sediments (40.86); in C.
nebulosum, fish (100) and in P. abbreviata as insects (17.16),
fish (40.00) and sediments (34.28).
The IFD (%) values of food items considered to be of
primary importance in E. bifasciatus, E. sexfasciatus, P.
pulcher and T. guineensis were insects (91.84); insects (67.95)
and crustaceans (18.16); fish (18.53), detritus (30.49) and
sediments (45.56); and algae (75.76) and plants (15.16)
respectively as shown in Table 7.
IFD (%) values of food items considered to be of primary
importance in C. nigrodigitatus, E. fimbriata, S. barracuda
and S. melanotherodon were crustaceans (62.29), molluscs
(20.75) and fish (13.21); algae (65.82) and crustaceans
(16.16); fish (93.33); and algae (28.89), plants materials
(42.10) and nemata (10.53) respectively as seen in Table 8.
IFD (%) values of food items considered to be of primary
importance in P. jubelini, P. peroteti, T. goreensis and T.
teraia were crustaceans (53.17), annelids (11.40) and fish
(32.28); fish (86.67) and detritus (13.33); crustaceans (88.89),
sediments (11.11) and detritus (13.33); and sediments (100)
respectively as shown in Table 9.
American Journal of Biology and Life Sciences 2014; 2(5): 122-134 130
Table 9. Analysis of stomach contents of P. jubelini, P. peroteti, T. goreensis and T. teraia by %RF, %PP and %IFD methods in Station 2 in Qua Iboe River,
Nigeria.
Food items
P. jubelini P. peroteti T. goreensis T. teraia
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Crustacea
Penaeid shrimp 11.77 10.00 7.60 50.00 88.89 88.89
Crabs 17.65 40.00 45.57
Annelida
Polychaetes 23.54 15.00 11.40
Fish
Bones 17.65 25.00 28.48
Scales 11.77 5.00 3.80
Fish remains 33.33 86.67 86.67
Detritus
FPOM 11.77 3.33 2.53 33.33 10.00 10.00
CPOM 5.88 1.67 0.63 33.33 3.33 3.33
Sediments
Sand grains 50.00 11.11 11.11 100 100 100
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
Table 10. Analysis of stomach contents of B. soporator, E. aeneus, P. elongatus and P. quadrifilis by %RF, %PP and %IFD methods in Station 2 in Qua Iboe
River, Nigeria.
Food items
B. soporator E. aeneus P. elongatus P. quadrifilis
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Crustacea
Shrimp 15.79 25.11 32.76
Crab remains 7.90 12.55 8.19
Mysis 15.80 12.14 7.92 50.00 77.78 77.78
Copepods 5.26 2.51 1.09
Fish
Bones 100 100 100 13.16 19.25 20.93
Scales 10.53 10.53 9.47
Flesh 15.71 20.55 16.37 50.00 22.22 22.22
Fish remains 100 100 100
Detritus
FPOM 7.90 2.51 1.64
Sediments
Sand grains 7.90 2.51 1.64
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
Table 10 illustrated the significant values of IFD (%) of
food items considered to be of primary importance for B.
soporator to include fish (100); in E. aeneus, fish (100); in P.
elongatus, crustaceans (49.96) and fish (46.77); and in P.
quadrifilis, crustaceans (77.78) and fish (22.22).
The %IFD of food items considered to be of primary
importance in L. dumerili, L. falcipinnis, L. grandisquamis
and M. curema included algae (19.06), plants (10.65),
detritus (11.78) and sediments (57.95); algae (21.86), detritus
(15.21) and sediments (67.36); algae (10.91), detritus (14.15)
and sediments (63.34); and algae (41.30) and sediments
(38.71) respectively as shown in Table 11.
However, high values of unidentified foods were recorded
in STN 1 for E. calabaricus (35.18), I. henrgii (39.99), X.
nigri (43.75), M. electricus (19.71), B. callipterus (19.54), B.
longipinnis (22.79) and S. melanotherodon (15.79) but low
131 Imaobong Emmanuel Ekpo et al.: Studies on the Food Composition and Feeding Pattern of Fish Communities in Qua Iboe River,
Niger Delta Region of Nigeria
value was observed only in L. falcipinnis (0.07) in STN 2.
Table 11. Analysis of stomach contents of L. dumerili, L. falcipinnis, L. grandisquamis and M curema by %RF, %PP and %IFD methods in Station 2 in Qua
Iboe River, Nigeria.
Food items
L. dumerili L. falcipinnis L. grandisquamis M. curema
Percentages
RF PP IFD RF PP IFD RF PP IFD RF PP IFD
Algae
Bacillariophyta 28.75 19.58 11.76 29.75 16.71 9.49 31.54 17.87 9.80 61.12 44.83 39.38
Chlorophyta 7.18 5.26 2.62 4.01 2.08 0.47 2.57 1.74 0.32
Dinophyta 7.79 5.16 1.88 5.63 3.09 11.33 1.54 0.70 0.13 5.56 3.45 2.15
Myxophyta 2.99 6.59 2.80 3.61 2.08 0.57 4.36 3.37 0.66
Plant materials
Leaf fragments 8.98 9.07 10.65 4.82 3.38 2.07 9.23 9.07 10.18
Insecta
Chironomid larvae 1.21 1.42 0.22
Insect remains 1.61 0.87 0.19
Crustacea
Conchoecia 3.21 1.96 0.80 1.54 1.13 0.21
Calanoids copepod 2.41 1.31 0.26
Mysis 0.60 0.83 0.07
Harpaticoid copepod 1.61 0.87 0.19 2.05 1.31 0.33
Protozoa
Foraminifera 3.41 1.64 0.39 1.54 0.96 0.18
Tintinnida 4.11 2.88 0.52
Nemata 0.60 0.41 0.03 2.41 1.53 0.47 1.28 1.05 0.16 5.56 3.45 2.15
Fish
Scales 1.80 2.06 0.49 4.02 2.84 1.42 1.54 1.05 0.20
Detritus
FPOM 5.99 3.30 2.59 10.04 11.56 14.71 9.48 8.81 10.16 5.56 10.35 6.46
CPOM 8.98 7.83 9.19 2.01 1.96 0.50 6.16 5.32 3.99 5.56 3.45 2.15
Sediments
Mud 8.38 9.27 10.16 6.43 5.45 4.44 11.53 30.51 42.79 5.56 6.90 4.31
Sand grains 11.98 30.39 47.79 12.44 39.91 62.92 11.53 14.65 20.55 11.11 27.59 34.40
Unidentified foods 0.80 0.65 0.07
FPOM = Fine Particulate Organic Matter; CPOM = Coarse Particulate Organic Matter
4. Discussion
The knowledge of the diet of a species in nature is
important for the establishment of its nutritional needs and of
its interaction with other organisms [31], and the presence of
various food types (plants, animal, detritus and sediments) in
their stomachs is an indication of their feeding habits. The
food items have their origins from all habitats of the aquatic
system – surface, mid-water and bottom; from within and
outside the river system. Mud, sand grains and sediments
were picked from the bottom of the river. [32] in agreement
with these observed trends showed that C. tamandua in
Anambra River was able to exploit all food niches (bottom,
mid-water and water surface) in its habitats; thus exhibiting
wide plasticity (i.e. high trophic flexibility) in its feeding
behaviours. [33 and 34] had in agreement with this finding
reported that autochthonous and allochthonous insects
constituted important proportion of food of many fish species
inhabiting the Anambra river system. However, this report
however is in consonance with the reports of [35, 36 and 32]
that many tropical fresh water fishes have a broader trophic
spectrum during the rainy (flood) season.
Of the 543 specimens examined, 204 (37.57%) had empty
stomachs, 79 (14.55%) had full stomachs whereas the
partially full: 63 (11.60%), 89 (16.39%) and 82 (15.10%)
were for ¾, ½ and ¼ respectively. In all, the proportion of
fish with food in the stomachs were higher (339; 62.43%)
than stomachs without food (204; 37.57%). This implies
there is a higher percentage of full stomachs and hence, a
high feeding intensity. The abundance of a rich food resource
enabled the fish to have a wide variety of choices to make
particularly in the estuarine zone. This agrees with the
observations of [8, 37] but this finding is not in consonance
with [38] in which a higher number of empty stomachs was
reported in Anambra River.
Food dominance varied from one species to another and
from one station to another. Generally, the dominant food
items were fish and sediments. Some species were found to
ingest different fish parts and whole fish in their diets; for
instance, B. soporator (100%), C. nebulosum (100%) and S.
barracuda (93.33%). A greater number of the species fed on
mud/sand grains; which must have been incidentally taken
along with other targeted food items. Sediment constitutes
important food resource since they have attached microbes
and nutrients. [37] reported that inclusion of sand / mud as
food item is an indication that the species feed close or even
at the bottom of the water. However, unspecialized feeders
American Journal of Biology and Life Sciences 2014; 2(5): 122-134 132
(feeding on both plants and animals) have been reported to be
a feeding pattern according to abundance of items in the
environment [36 and 39].
High food richness was recorded in this research as
revealed by the forty-two food items ingested which was re-
grouped into thirteen different major items. The ingestion of
diversified and non-selectivity of food items by fish species
confirms the findings of [9, 40, 41 and 37]. More food items
occurred in estuarine than in freshwater zones. Estuaries have
been considered as feeding, spawning and nursery grounds as
a result of abundance of food materials. They have been
linked with high productivity partly due to the mixing of the
freshwater with the high saline water and leaf litter
decomposition. Food item availability is dependent on
several factors: type of water body, species type and [8]
reported that seasonal diversity of food items could influence
food habits, diet and feeding intensity of fish.
Fish can broadly be classified into categories based on
their predominant feeding habits [36] and these could be
determined by their primary food item(s). The feeding habits
of the fish in the two zones appeared to be similar but there
are, however, slight variations. In the freshwater zone, three
broad trophic groups (herbivores, predators, and detritivores)
and in the estuarine zone, four broad groups (algivores,
herbivores, predators and detritivore) were identified.
Considering all, most of the species were predators feeding
on insects, crustaceans and fish. This finding deviates from
the findings of [30] in which most of the freshwater fishes in
Cross River inland wetlands were detritivores. Findings in
this study that the mugilids are “detritivore-algivores”
feeding mostly on sediments, detritus and algae agree with
observations by [11] who described them as detrital feeders.
The high percentage of plant materials, algae, and detritus
agree with findings of [42, 9, 43 and 30] who reported that
members of this family were plankton, higher plants and
algae feeders or macrophagous as well as mud suckers.
However, the observations of [44] are at variance with this
result who reported that they were euryphagous except for
bottom feeders in the family’s Cichlidae and Mugilidae. Also,
[45] reported that analysis of trophic niches of the available
fish species in River Ganga basin indicated dominancy of
carnivorous (19 species) in Ken and omnivorous (23 species)
in Betwa.
The six stomachs of P. africana investigated were all
empty. However, [46] classified P. obscura as piscivore,
although the stomachs of the 2 specimens caught in Upper
Ogun River were empty. Fish and sediments were the
dominant food items. The high IFD values derived from
other fish, such as chunks of fish flesh among the stomach
contents of H. fasciatus and C. aluuensis suggest that they
are more of scavengers than piscivores. This type of food
item is probably derived from dead or dying fish caught in
set nets or discarded fish found scattered about in the beach
especially in the estuarine zone. Higher values of
unidentified food items (ranged from 15.79% in S.
melanotherodon – 43.75% in X. nigri) and a greater number
of species (7) were recorded more in the freshwater zone than
(only one species: L. falcipinnis, 0.07%) in the estuarine zone.
The inability to identify these materials might be due to the
fact that digestion had gone far. But they constitute very
important matter in the gut since they occupied space
agreeing with several authors working on food and feeding
habits of fish species [9, 47, 48 and 34].
The ingestion of various sources of dietaries by these fish
species help to reduces possible competition between them to
the minimum and encourages healthy coexistence. The fish
species are euryphagous, feeding on several food items
ranging from plant and animal to non-living matters.
Interrelationship existed between the freshwater and
estuarine fish which were classified as algivores, herbivores,
predators and detritivores; implying a balanced system and
which all the species could generally be described as
omnivores.
5. Conclusion
Thirteen major items made up of forty-two simpler food
items occurred in the stomachs of these fish species. Food
dominance varied from one species to another and from one
station to another with fish and sediments being the highest
and dominant. The six specimens of P. africana had empty
stomachs. Percentage of stomachs with food was higher than
those without food. Feeding interrelationship existed between
the freshwater and estuarine fish species which were
classified as algivores, herbivores, predators and detritivores.
These wide feeding habits aid in reduction of possible
competition between them to the minimum and encourage
healthy coexistence. This work has bridged the gap by
furnishing information on multispecies food and feeding
habits of fish in this river. There is an urgent need to study
the ecosystem’s functioning which lays in the analysis of the
energy flow among the fish species.
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