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Journal for Studies in Management and Planning
Available at http://internationaljournalofresearch.org/index.php/JSMaP
e-ISSN: 2395-0463
Volume 01 Issue 11
December 2015
Available online: http://internationaljournalofresearch.org/ P a g e | 239
Abundance and Monthly Composition of Fish Species of Ikpa River
at Ntak Inyang, Akwa Ibom State, Nigeria.
Usanga, Ekpeno Etiese
Department of Zoology, University of Uyo, Uyo, Nigeria
ekpenousanga@yahoo.com
Abstract
The fish species of Ikpa River were collected
at Ntak Inyang, Ikpa River in Itu, Akwa
Ibom State, Nigeria for six months (May to
October, 2009) using cast nets and gill nets.
Nineteen freshwater fish species belonging
to twelve families and five orders in a total
of four hundred and fifty-six (456) fish
specimens were encountered. Family
Cichlididae constituted the most abundant
(49.12%), followed by Characidae
(41.23%). Brycinus longipinnis was the
commonest fish species (29.44%), while
Phago loricatus (0.21%), Papyrocranus afer
(0.21%) and Schilbe intermedius (0.21%)
where the least abundant. Differences in
monthly distribution of fishes were not
statistically significant (P > 0.05; F = 0.17).
Keywords: Ichthyofauna, Iyere, Esuk Itam,
Ikpa, Itu, Akwa Ibom.
1. Introduction
The inland freshwaters in Nigeria constitute
about 12.4% of the total surface area
(Olaosebikan and Raji, 2004). These inland
waters contain the richest collection of
fishes in West Africa (Idodo-Umeh, 2003
and Olaosebikan and Raji, 2004). However,
due to inadequate management of the
fisheries resources and environmental
degradation of the water bodies, this rich
fish resources is on the decline (Odo et al.,
2009). To maintain a sustainable
exploitation of these resources, a
comprehensive knowledge of the fish
composition of the waters is of necessity.
This study is a preliminary survey of the fin
fishes that can be found in Ikpa River at
Ntak Inyang, and further add to the
compendium of the freshwater fishes of
Nigeria. List of African freshwater fishes
can be found in Boulenger (1916) to include
976 species, referable to 185 genera and 43
families. Works on the fishes of Nigerian
waters can be found in Welman (1948),
Udoidiong (1991) Levesque et al. (1992),
Teugels et al. (1992), Ita (1993), Ekwu and
Sikoki (2005), Idodo-Umeh (2003).
2. Materials and Method
2.1 Study Area
The research was carried out at Ntak Inyang
bridgehead on Ikpa River, popularly known
as Esuk Itam or Iyere in Itu Local
Government area of Akwa Ibom State,
Nigeria. Ikpa River is a small perennial
tributary stream located west of the lower
Cross River in South Eastern Nigeria (King,
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Journal for Studies in Management and Planning
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e-ISSN: 2395-0463
Volume 01 Issue 11
December 2015
Available online: http://internationaljournalofresearch.org/ P a g e | 240
1994). It lies between latitude 5°2ʹ57.84ʹʹ N
and longitude 8°3ʹ5.04ʹʹ E (ng.geoview.info).
It has a main channel length of 53.3km and
an area of 516km2
, with a mean depth of
2.0m and a mean width of 12.5m (King,
1994). The river has a considerably rich
flora on its banks. These include Elaeis
guineensis, Raphia hookeri, Raphia
vinnifera, aquatic macrophytes such as
Nymphaea, Vossia and Crinium spp. (King,
1989 and Teugels et al., 1992). The stream
surface temperature varies from 23.3°C to
28.0°C with season. Secchi disc
transparency varies from 12.5cm to 100cm,
while pH is 6.6-7.7 (King, 1989). Current
velocity is 3.5 – 6.9cm/s. More information
on Ikpa River basin can be found in King
(1989) and Teugels et al. (1992).
2.2 Sampling Method
Fishes were collected at Ntak Inyang (Iyere)
fortnightly for a period of 6 months, starting
from May to October, 2009 using cast nets
of 0.5cm mesh size and gill nets. Sampling
was done randomly at different points along
the stream channel at Ntak Inyang.
Specimens collected were transported to the
laboratory in a cooler. Preservation was
done using 10% formaldehyde solution.
Fishes were sorted and identified using
Idodo-Umeh (2003) and Olaosebikan and
Raji (2004).
2.3 Data Analysis
The monthly species by composition was
noted, and the monthly percentage
occurrence of each species and family
computed as follows:
RA = n/Nx100 (1)
Where, RA is relative abundance, n is
number of individual fish species and N is
total number of all the fish species.
The Shannon-Weaver’s and Simpson’s
Indices of diversity, as well as Evenness
were computed using PAST 3.0 software.
One-Way ANOVA at 5% level of
probability was used to determine monthly
significant differences.
3. Results and Discussion
3.1 Relative Abundance and Diversity
A total of four hundred and fifty-six (456)
fin fish specimens were collected throughout
the sampling period of six months. Of this
number, nineteen fish species under twelve
families and five orders were discovered
(Table 1). The most abundant species was
Brycinus longipinnis, 29.82%, whereas the
least abundant species were Papyrocranus
afer, Phago loricatus and Schilbe
intermedius each with relative abundance of
0.22% (Table 2). The Perciformes (51.31%)
constituted the commonest order, whereas
the Osteoglossiformes (0.22%) constituted
the rarest (Fig. 1). The commonest families
were Cichlidae (49.12%) and Characidae
(41.23%) (Fig. 2). Diversity Indices are as
shown on Table 1.
3.2 Monthly Species by composition
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The highest monthly abundance in terms of
number of specimens was in May and July
with 91 specimens each (Table 2). Among
the most abundant species, Brycinus
longipinnis was observed to be highest in
abundance in May, whereas it occurred least
in September (Table 2). However, these
differences in monthly distribution of fishes
indicated no statistical significance (P >
0.05, F = 0.17).
3.3 Discussion
The results of this research agree with a
similar study at Ntak Inyang stream by Udo
(2012), where 19 species representing 13
families were recorded. The results further
indicate a high level of richness and
diversity in species at Ntak Inyang, based on
Margalef’s index (2.94) and Shannon- Weiner’s diversity index (2.112). Udoidiong
and King (2000) reporting on the fish faunal
assemblages of two first order, two second
order and one third order streams in Akwa
Ibom State had an ichthyofaunal
composition of 55 species from 43 genera
and 24 families. Of these, Ikpa stream (Ikpa
River) had richest assemblage of 40 species,
35 genera and 24 families. In comparison to
researches on other rivers in Nigeria, Victor
and Tetteh, (1988) reported 58 species from
Ikpoba river; 167 different species from the
Cross river (Teugels et al., 1992); 52 species
from Anambra river (Odo et al., 2009).
According to Koutrakis et al. 2(000), and
Emmanuel, (2009), the interaction between
fish and its habitat (physical, as well as
biological characteristics) may be factors in
predicting changes in overall abundance,
breeding population size and other aspects
of population structure. The difference in
results between this study and those from
other authors here cited can be attributed to
the small size of Ntak Inyang stream, which
is a 3rd order tributary of Cross river. Also
affecting the result of this study is the
difference in sampling periods and
frequency. In Odo et al. (2009), the fish
composition of Anambra River was studied
for a period of 2 years. Longer duration like
this would allow collection of a wide
diversity of fishes.
Udoidiong and King (2000) recorded
Cichlidae as the most abundant fish family
in Iba-Oku Stream, Ikpa River. In contrast,
Onuoha et al. (2010) reported Characidae as
the most abundant fish family at Ntak
Inyang, Ikpa River; Udo (2012) reported
Malapteruridae as the dominant family at
Iba Oku, Ikpa River. Cichlid fishes are
adapted for bottom feeding, surface feeding
and can feed on a variety of food items
(Greenwood, 1981). Based on their high
abundance, the cichlid and characid fishes
are likely resident to Ikpa River where
planktonic algae are in abundance.
According to King (1994), Papyrocranus
afer is a resident species of Ikpa River and
inhabit quiet, gently flowing vegetated areas
of the stream. Human activities such as
commercial sand dredging (which is a major
activity in the stream) cause perturbations to
the water. This would cause the fish
population to retreat to the inner reaches of
