Vol. 16(6), pp. 931-938, June, 2020
DOI: 10.5897/AJAR2019.14420
Article Number: A06F2E764080
ISSN: 1991-637X
Copyright ©2020
Author(s) retain the copyright of this article
http://www.academicjournals.org/AJAR
African Journal of Agricultural
Research
Full Length Research Paper
Response of wild smooth-head catfish (Clarias
liocephalus) fingerlings reared in earthen ponds
Jane Yatuha1*, Jeremiah Kang’ombe2, Daniel Sikawa2, Lauren Chapman3 and
Justus Rutaisire4
1
2
Mbarara University of Science and Technology, P. O. Box 1410, Mbarara, Uganda.
Lilongwe University of Agriculture and Natural Resources, P. O. Box 219, Lilongwe, Malawi.
3
McGill University, Montreal, QC, Canada.
4
National Agricultural Research Organization, Entebbe, Uganda.
Received 22 August, 2019; Accepted 1 June, 2020
Clarias liocephalus, an important small fish in the diet of rural households, is threatened by wetland
degradation and overfishing for use as live bait. This study aimed at establishing the survival,
condition, growth rate and feed utilization indices of C. liocephalus wild fingerlings reared outside the
wetland environment through a feeding experiment. Fingerlings were fed with an isocaloric feed with
four levels of crude protein for eleven weeks. Results showed that C. liocephalus could endure wide
ranges of water temperatures, low levels of dissolved oxygen and could efficiently utilize artificial
feeds. The 35% crude protein diet was the best utilized with a feed conversion ratio of 4.18. The mean
specific growth rate was 2.2 to 2.5%, which is comparable to that of other reared Clariidae. Fish
condition was best with the 30 and 35% diets and mean survival was 46.44% (±3.159SE) and not
significantly different (p<0.05), for the four diets. This new information is useful as reference in
recommending the species for aquaculture. Rearing C. liocephalus could also reduce rural malnutrition
and fish-protein deficiency especially in rural poor communities. Rearing trials for longer periods and
measurement of other key production indices required in aquaculture of C. liocephalus were
recommended.
Key words: Wetland habitats, micronutrients, hapas, fish feeds.
INTRODUCTION
Today, national development plans are focusing on
ensuring economic and food security for the ever
increasing human population, projected to hit 8.6 billion
by 2030, alongside strategies to manage the apparent
degradation of terrestrial and aquatic ecosystem
resources (Bierbaum and Cowie, 2018). Fisheries and
aquaculture constitute a substantial sector in agricultural
development for economic and nutritional purposes and
its contribution in the alleviation of nutritional and
economic insecurity is upheld from global to local
perspectives (FAO, IFAD, UNICEF, WFP, WHO, 2019).
Fish provide an essential protein-rich component to the
*Corresponding author. E-mail: jyatuha@must.ac.ug.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution
License 4.0 International License
932
Afr. J. Agric. Res.
human diet especially in communities with predominantly
carbohydrate-based diets common in developing
countries (Thilsted, 2012). As a rich source of multiple
micronutrients including zinc and iron, fish have the
capacity of meeting the micronutrient deficiencies
predominant among the vulnerable groups in subSaharan Africa (Phillips et al., 2015).
As captured fisheries become unsustainable due to
over-fishing, habitat loss and aquatic environmental
pollution, aquaculture is increasingly being considered as
the alternative to the development and improvement of
fisheries resources and revitalization of the ecosystems.
Investment in environmentally sustainable aquaculture
production presents opportunities for food and economic
securities particularly for developing countries (World
Bank, 2013).
Uganda’s per capita fish consumption reported to be
about 6 kg person-1 year-1 (MAAIF, 2004; NARO, 2017),
is still well below the WHO-FAO recommended level of
17.5 kg person-1 year-1. The slight increase, despite the
greatly reduced wild fish stocks, could partly be attributed
to the growing aquaculture industry, now at about
100,000 tonnes anum-1 (NARO, 2017). However, the high
price tag on fish in Uganda today dictates that only the
economically stable communities can access it.
According to Uganda’s Demographic Health Survey
(UDSH) report of 2016, the indicators of malnourishment
that include stunting and iron deficiency are specifically
high among the rural poor communities (Uganda
Demographic and Health Survey [UDSH], 2017). It is
worth noting that the human population in Uganda is now
at >39 million and 76% of this population lives in rural
areas as indicated in the 2018 statistical abstract
(Uganda Bureau of Statistics [UBOS], 2018). It is
possible that a large proportion of the Ugandan rural
population could be nutritionally deficient in essential
proteins and micronutrients partly provided through
adequate fish consumption.
Evaluating the potential of some locally available small
fish like Clarias liocephalus, which may not be as
expensive to rear but nutritionally competent, could make
a significant contribution towards addressing the problem
of fish-food deficiency and indirectly reduce malnutrition
and poverty in rural poor households. Since most of the
local small fish species are not domesticated (Kumar,
2010) and their natural habitats, especially wetlands, are
threatened (Chapman et al., 2001; Ministry of Water and
Environment, 2018), it is increasingly becoming
necessary to promote the rearing of such fish, at least
from the perspective of conservation. The motivation
behind this study was to test whether the Clariidae catfish
C. liocephalus, a small wild wetland fish species, could
survive and grow outside its natural environment thriving
on an artificial diet. The study hypothesized that C.
liocephalus could grow and survive under culture
conditions and that it could offer parallel nutritional
attributes like other established cultured fishes especially
the commonly cultured species of tilapias and Clarias
gariepinus. The choice for C. liocephalus was based on
the fact that it is highly acceptable in the diet of local
people in the study area; seems to tolerate a wide range
of environmental conditions and that its survival in the
wild is threatened by habitat loss and the unregulated
live-bait market (Ajangale, 2007; Yatuha et al., 2012). C.
liocephalus exhibits some basic qualities required in a
potential aquaculture fish species like being a generalist
feeder and possessing an air-breathing accessory organ
to boost survival in environments with low dissolved
oxygen levels (Yatuha, 2015); however, its production
indices which are important for fish farmers, are not yet
adequately defined and its response outside its natural
wetland environment is poorly documented. A feeding
experiment was mounted to define the diet at which C.
liocephalus would attain maximum growth response and
nutrient utilization. The study specifically evaluated the
effect of dietary crude protein level on growth
performance, feed utilization, survival and general
condition of wild C. liocephalus fingerlings kept under
pond conditions for eleven weeks. Determining the
minimum feed needed to meet the species protein
requirements and achieve maximum growth is important
because there is an economic advantage in identifying
and feeding fish at an optimal rate, that is, at the lowest
feed conversion ratio (FCR) and highest specific growth
rate (SGR) point (De Silva and Anderson, 1995; Kim and
Lee, 2009). Knowledge of the growth rate and proximate
body composition of a species for a given diet level
provides a useful guideline in selecting a diet that is both
nutritionally adequate and most affordable. Principal
factors that determine fish growth and body composition
are important when considering the role of fish as a
source of nutrition (Ahmed et al., 2010).
MATERIALS AND METHODS
About 2500 C. liocephalus fingerlings of mean wet weight of 2.83 g
(±0.003SE) were fished from Kigambira wetland, found in Lake
Mburo National Park Uganda, using local basket traps. The wetland
is a constituent of the Rwizi-Rufuha wetland system that drains the
southwestern part of the Lake Victoria basin. The fingerlings were
allowed to acclimate in a collection tank for seven days and were
fed on a 30% crude protein (CP) general juvenile Clarias diet
(Jauncey et al., 2007).
An isocaloric complete commercial floating diet with 4 levels of
crude protein (CP) graded as low protein (25% CP), medium protein
(control: 30% CP), high protein (35% CP) and very high protein
(44% CP) was sourced and its proximate composition established
(Table 1) before they were used for the experimental feeding. Each
of the test diets was replicated four times giving a total of 16 units.
The feed pellet size for each of the four diets was graded to 3±0.5
mm, which is 30% of the average gape size of C. liocephalus
fingerlings (Yatuha, 2015).
The experimental fish were reared in a semi-intensive setting in
an earthen fish pond which was selected and prepared from a set
of other fish ponds at Mbarara Zonal Agricultural Research and
Development Institute (MBAZARDI) near Mbarara University of
Science and Technology in Mbarara municipality, Southwestern
Yatuha et al.
933
Table 1. Proximate composition (%) of the test diets used in C. liocephalus feeding experiment.
Diet
25% CP
30% CP
35% CP
44% CP
Diet code
1
2
3
4
Dry matter (g)
27.78±0.026SE
33.38±0.005SE
38.15±0.044SE
47.82±0.112SE
Ash (g)
6.20± 0.039SE
6.93± 0.060SE
7.35± 0.066SE
6.33± 0.083SE
Crude fat (g)
8.79± 0.013SE
14.69± 0.102SE
20.56± 0.186SE
28.87±0.023SE
Crude fibre (g)
3.44± 0.008SE
3.38± 0.024SE
3.15± 0.006SE
3.64± 0.086SE
Crude protein (g)
24.99± 0.024SE
30.20± 0.017SE
34.62± 0.040SE
43.71± 0.021SE
and 7:00 am in the morning and between 12:00 and 1:00 pm in the
afternoon. The dissolved oxygen (DO) and pH of the pond water
were measured twice a week between 10:00 and 12:00 h. A digital
thermometer, a pH meter (pH meter model HANNA HI98129) and
DO meter (Oxy meter model YSI 550A) were used for measuring
the said water quality parameters.
At weekly intervals, all the fish in each hapa were removed and
counted to establish the survival. Fifty percent (50%) of the fish
were randomly sampled and individually weighed and measured for
total length.
The mean weight gain (WG) was established by subtracting the
mean initial weight (g) from the final mean weight.
Figure 1. Set up of experimental units in the pond
for the feeding experiment of C. liocephalus.
WG = Final mean weight - Initial mean weight and the percent
weight gain (WG %) = [Final mean weight (g) - Initial mean body
weight g) / Initial body weight] × 100
(1)
The Feed Conversion Ratio (FCR) was expressed as the proportion
of dry feed fed per unit live weight gain of fish calculated as:
Uganda. Mbarara municipality is at altitude 1,432 masl; 0.6167° S,
30.6568° E; average annual temperature 25°C and rainfall of 1125
mm. The pond was fitted with 16 nylon hapas of size 1.73 m2 (1.2
m × 1.2 m × 1.2 m) and a mesh size of 1 mm. The hapas were
arranged at a depth of 1.3 m in a line at a distance of 1.5 m
between any two hapas (Figure 1).
At the start of the experiment, after the fish had not been fed for
24 h to enable them to empty their stomachs, one thousand six
hundred (1 600) fish with an average weight of 2.83 g (±0.003SE)
body weight were selected, visually identified, individually weighed
and measured for total length and randomly assigned into the 16
hapas (experimental units) at a stocking rate of 100 fingerlings per
hapa. The four diets in their four replicates were randomly assigned
to the 16 stocked experimental hapas. A general commercial
Clarias feed formula (30% CP) was used as a control having been
a standard catfish diet for a long time (Legendre, 1986; Robinson et
al., 2001). Since there were no data on the nutrient requirements of
juvenile C. liocephalus, it was acceptable to adopt from closely
related species (Kaushik, 2000).
The experimental fish were fed at 5% body weight, regarded as
apparent satiation (Jauncey, 1982) two times a day for 11 weeks
and records of daily feed intake were kept. The duration of the
feeding experiment was deemed adequate to get the required
results since results of growth performance in Clarias fingerling
feeding experiments have been realized from experiments of six
weeks (Solomon and Okomoda, 2012) or eight weeks (Odulate et
al., 2014; Adebisi and Ologhoba, 1998). About 10% of the pond
water was exchanged for fresh water once every three days, from a
common reservoir that supplied the other ponds on the fish farm.
To prevent clogging by algae and left over feeds, the hapas were
washed weekly during the time of weekly measurement of the fish.
Data collection and analysis
Three water quality parameters were recorded in this study. The
general pond water temperature was measured daily between 6:00
FCR = Dry weight of feed (g) / Wet weight gain by fish (g)
(2)
The Specific Growth Rate (SGR), that is, the weight gained by fish
per day was calculated as:
SRG = [Ln (W2) - Ln (W1) × 100] / T2 - T1
(3)
where W2 = Weight of fish at time T2, W1 = Weight of fish at time T1,
Ln = Natural log.
Survival (%) was calculated as follows:
Survival = (Initial number at start of experiment - Number at end of
experiment) × 100
(4)
Condition factor: Fulton’s Condition Factor (Froese, 2006) was
calculated thus:
K = (100W) / L3
(5)
where K=Condition factor, L=Standard length (cm) and W=Wet
weight (g).
Data were analyzed using SPSS Inc.17 (IBM Corp. Chicago,
USA) and Minitab Inc. 14 statistical software. Relationships in the
datasets were subjected to correlation-regression analyses and
variations to ANOVA followed by Tukey HSD test (or its nonparametric Kruskal Wallis Test) at a significance threshold of 0.05.
RESULTS
The overall mean dissolved oxygen of water in the
experimental pond was 1.39 mg l-1, indicating a general
poor oxygen circulation in the experimental units. Mean
pH was 6.65, well within the range of freshwater fishes
and the mean morning and afternoon temperatures were
934
Afr. J. Agric. Res.
Table 2. Mean dissolved oxygen (mg/L) pH and temperature (oC) in the experimental pond water
through the experimental period.
Week
Mean DO Mg/L
pH
1
2
3
4
5
6
7
8
9
10
11
2.17±0.58
1.35±0.22
1.27±0.24
0.77±0.17
1.59±0.12
1.69±0.50
1.05±0.12
1.09±0.15
1.19±0.08
1.40±0.10
1.5±0.24
6.11±0.28
6.32±0.71
6.51±0.19
6.81±0.06
7.03±0.11
6.65±0.35
6.8±0.00
6.77±0.75
6.72±0.02
7.07±0.00
7.14±0.14
Temperature (mean and SE)
Morning
Afternoon
19.72±0.456
27.59±0.525
20.81±0.998
28.22±0.872
19.33±0.235
27.33±1.269
21.76±0.495
29.38±0.416
20.53±0.461
28.69±0.779
18.96±0.460
26.55±0.599
19.52±0.367
26.72±0.330
19.81±0.481
27.12±0.355
18.22±0.236
27.38±0.505
17.35±0.109
27.75±0.512
18.57±0.370
28.30±0.336
Figure 2. Fish body weight increment (a) and total length increment
(b) in C. liocephalus experimental fish over the 11 weeks period of
experimental feeding.
19.36°C ±0.153SE and 27.53°C±0.162SE, respectively.
The results for DO, pH and temperature over the
experimental period are summarized in Table 2.
The overall growth response of C. liocephalus
fingerlings in terms of mean weight gain and length
increment showed a positive trend especially after the 5th
week of the feeding experiment (Figure 2). While there
was no significant difference in weight and length
between treatment groups at the start of the feeding
experiment (Kruskal Wallis Test P=0.122, n=1600); the
difference became significant (P<0.01) by the end of the
experiment (Kruskal Wallis Test P=0.001 and 0.000 for
weight and TL, respectively). Fish fed on the diet of 30%
CP registered the highest weight gain and had the
heaviest individual fish by the end of the experiment (20.7
g) while that of 25% CP had the lowest weight gain and
had the lightest individual fish that weighed only 2.2 g at
the end of the experiment (Table 3).
The mean feed conversion ratio (FCR) of the fish
fed on the four test diets over the experimental period
was 5.01, 4.18, 4.53 and 4.85, respectively (Table 3). It
was noted that FCR values were high in the first weeks of
the experiment and steadily improved with time (Figure
3). There was a significant difference in FCR between the
first and last weeks of the experiment period (FCR 23.7,
p<0.001). Specific growth rate was the highest in the 35%
Yatuha et al.
935
Table 3. Growth response parameters of C. liocephalus fed on four different diets over 11 experimental weeks (±SE).
Parameter
Initial mean weight (g)
Final mean weight (g)
Final minimum weight (g)
Final maximum weight (g)
Initial mean TL (cm)
Final mean TL (cm)
Initial mean Feed Conversion ratio (fcr)
Final Mean Feed Conversion ratio (fcr)
Condition (K)
Specific growth rate (SGR)
Survival (%)
Total feed fed (g)
D1 (25% CP)
3.14±0.06
8.52±0.36
2.2
14.6
7.58±0.05
10.14±0.16
5.74±0.05
3.32±0.10
1.04±.0053a
2.10
43
312
Treatment
D2 (30% CP)
D3 (35% CP)
3.09±0.07
2.98±0.06
9.40±0.31
9.71±0.27
2.2
3.7
20.7
19.7
7.59±0.05
7.45±0.06
10.30±0.12
10.36±0.10
6.77±0.21
7.46±0.22
3.18±0.06
2..98±0.04
1.06±.0047b
1.05±.0052b
3.03
3.10
46
49
451
474
D4 (44%CP)
3.21±0.06
8.49±0.25
2.8
17.0
7.56±0.06
10.31±0.10
7.38±0.20
3.48±0.05
1.01±.0040a
2.81
47
457
*Mean values in the same row with different superscript are significantly different (ANOVA, P<0.05).
Figure 3. FCR trends of C. liocephalus fingerlings fed on 4 test diets over 11
weeks.
diet and the lowest in the 25% CP diet (Table 3).
Percent survival was 46.44% ±3.159SE for all the four
treatment diets. The individual means for diets 1 to 4
were 43, 46, 49 and 47%, respectively. Percent mortality
was the highest in the first four weeks, but dropped to
almost 0% from week 5 to the end of the experiment
(Figure 4).
The condition of fish fed on Diet 1 (25% CP) and 4
(40% CP) was poor and significantly different from fish
fed on Diets 2 (30% CP) and 3 (35% CP).
DISCUSSION
This study intended to establish whether C. liocephalus, a
wild wetland small catfish, could survive in an artificial
environment, utilize an artificial diet to grow in weight and
length, maintain good condition and adequately convert
the feed into fish flesh. The over 40% overall survival is a
clear indication that C. liocephalus can survive in an
artificial environment and on artificial diet and the fact that
some of the experimental fish greatly increased in body
936
Afr. J. Agric. Res.
Figure 4. Survival trends of C. liocephalus fingerlings fed on 4 test diets over 11 weeks
mass (from 5.5 g maximum at beginning to 20.7 g
maximum at end of experiment), is a positive indicator
that C. liocephalus could attain table size in a relatively
short period. However, there was size disparity within the
stocked fish in all the treatments although similar sized
fish were stocked at the beginning of the feeding
experiment. Size disparity is a common phenomenon in
catfish stocks during the initial stages of development (De
Graaf and Janssen, 1996). Since size-grading was not
done during the course of the experiment, size disparity
could be partly explained by the nature of the fish
species. Persistence of stunted individuals throughout the
study period could be attributed to poor seed quality
because the stocked juveniles were randomly picked
from the wild. Besides feed quality, seed quality is known
to be a very important factor in fish production (De Graaf
and Janssen, 1996; Pouomogne, 2008). Stunted growth
could also be attributed to starvation because of
competition with larger individuals. Since feeding was
done only twice a day, it is possible that less competitive
individuals could have starved. It has been reported that
when frequently fed, fish yielded more because dominant
individuals
become
less
aggressive
in
such
circumstances (Aderolu et al., 2010). Feeding three times
a day is known to be the most efficient frequency for
effective growth and nutrient utilization for juveniles and
fingerlings of C. gariepinus (Aderolu et al., 2010).
The feed conversion ratio (FCR) for the 4 treatments
was generally higher than expected given the typical 1.4
to 2.5 recorded in catfish production experiments
(Robinson et al., 2001). However, a consistent reduction
in FCR from high figures in the first weeks and low
figures in the last weeks was noted. This is an indication
that as the fish grew and became used to the feed,
utilization improved. If the experiment was to run for more
time (up to normal harvest time), the results suggest that
the FCR would have dropped to acceptable levels of two
and below. The FCR could also have been influenced by
the low DO levels since the water in the experimental
pond was not on a flow through design and therefore
poorly aerated. The oxygen levels were below the
required minimum most of the time during the experiment
(overall mean of 1.39 mg/l), and this could have
compromised the quality of the water. Low DO levels
have significant effects on fish growth as well as food
conversion (Chang and Ouyang, 1988). In poorly aerated
waters, catfish spend a lot of energy to obtain
atmospheric oxygen and this stresses the fish and lowers
its appetite and feed utilization (De Graaff and Janssen,
1996). Lack of flow-through water system and short
duration of experiment have been implicated for poor
values of FCR in other fish feeding experiments
(Mwangamilo and Jiddawi, 2003). The SGR of 2.2 to
2.5%, is comparable to that reported in other Clariidae
reared within an almost similar experiment duration
(Akinwande et al., 2009; Solomon and Taruwa, 2011).
Yatuha et al.
However, SGR in C. liocephalus was low compared to C.
gariepinus (5.7%) fed on a diet of maggots (Otubusin and
Ifili, 2000). The difference could lie in the source of feed,
duration of the experiment, seed quality and other
conditions in the experimental environment.
In the first four weeks of the experiment, mortality was
the highest and dropped to almost 0% in the last weeks.
The high mortalities could be attributed to handling stress
as well as high stocking density. One hundred fingerlings
in a 1 m3 hapa in a non-recirculatory water system could
have been stressful and a likely cause of mortality and
high survival after the stock fell by almost 50%. High
mortalities in the first weeks of feeding experiments have
been reported in other catfish (Akinwande et al., 2009).
The findings of this study indicate that C. liocephalus
has a number of attributes that could make it a suitable
choice for subsistence aquaculture in rural settings.
Subsistence aquaculture has the potential to contribute to
most of the relevant sustainable development goals
(SDGs). This is due to the family level of operations,
where work is well distributed, meaningful and
empowering. While there is no direct impact on poverty, it
does provide a regular supply of high quality protein,
sparing income for other food and living expenses. It is
also environmentally efficient, especially when integrated
into other farming activities. It can make households and
communities more resilient to economic or environmental
shocks.
CONCLUSIONS AND RECOMMENDATIONS
From the findings of this study, we conclude that C.
liocephalus can grow and survive outside its natural
wetland environment. The species can endure low levels
of DO and a wide range of temperature variations and
register a specific growth rate that is comparable to that
reported in other reared Clariidae. The species exhibited
a key aquaculture advantage in its ability to survive both
in hypoxic and hyperoxic water environments that are
typical of fish pond waters in a tropical rural setting.
Unlike some obligate air-breathers like Protopterus
species, which die if deprived of atmospheric oxygen, C.
liocephalus can survive under stress of both atmospheric
and dissolved oxygen. The survival of C. liocephalus in
turbid water ponds at low dissolved oxygen levels is a
positive indicator that the species has some desirable
qualities for survival in the prospects of climate change,
where predicted droughts will likely cause deterioration of
water quality. That C. liocephalus can withstand a wide
range of water quality parameters is an opportune coping
strategy to provide nutrition and revenue to rural
communities in the face of global demand for aquatic
food. Since the species has the required traits to be
raised in an artificial environment, further rearing trials for
longer periods and measurement of the rest of the
production indices required in aquaculture fish species
937
are recommended.
CONFLICT OF INTERESTS
The authors have not declared any conflict of interests.
ACKNOWLEDGEMENTS
The authors are indebted to RUFORUM and partners
who provided financial support for this study, Lilongwe
University of Agriculture and Natural resources, Mbarara
University of Science and Technology and Makerere
University for the expert support in the analysis of the
samples, National Fisheries Research Institute Kajjansi
and MbaZARDI for hosting the experiments.
REFERENCES
Adebisi MB, Ologhobo AD (1998). Growth performance and nutrient
utilization of fingerling Clarias gariepinus (Burchell fed raw and
cooked soybean diets. Aquaculture 76:119-126.
Aderolu AZ, Seriki BM, Apatira AL, Ajaegbo CU (2010). Effects of
feeding frequency on growth, feed efficiency and economic viability of
rearing African catfish (Clarias gariepinus, Burchell 1822) fingerlings
and juveniles. African Journal of Food Science 4:286-290.
Ahmed EO, Ali ME, Kalid RA, Taha HM, Mahammed AA (2010).
Investigating the Quality changes of raw and hot smoked
Oreochromis niloticus and Clarias lazera. Pakistan Journal of
Nutrition 9:481-484.
Ajangale NI (2007). The aquaculture potential of indigenous catfish
(Clarias gariepinus) in the Lake Victoria Basin, Uganda (Ph.D).
University of Stirling, UK.
Akinwande AA, Moody FO, Umar SO (2009). Growth performance and
survival of Heterobranchus longifilis, Heterobranchus bidorsalis and
their reciprocal hybrids. African Scientist 10:15-18.
Bierbaum R, Cowie A (2018). Integration: to solve complex
environmental problems. Scientific and Technical Advisory Panel to
the Global Environment Facility. Washington, DC.
Chang WYB, Ouyang H (1988). Dynamics of dissolved oxygen and
vertical circulation in fish ponds. Aquaculture 74:263-276.
Chapman LJ, Balirwa J, Bugenyi FWB, Chapman CA, Crisman TL
(2001). Wetlands of East Africa: Biodiversity, exploitation and policy
perspectives. In Wetlands biodiversity (pp. 101–132). Backhuys:
Leiden.
De Graaf JG, Janssen J (1996). Handbook on the artificial reproduction
and pond rearing of the African catfish Clarias gariepinus in SubSaharan Africa. (FAO Fisheries Technical Paper No. 362).
Amsterdam Netherlands.
De Silva SS, Anderson TA (1995). Fish nutrition in aquaculture.
Chapman and Hall, London. Food and Agriculture Organization of the
United Nations FAO (2013). Fish feeds and feeding: FAO Training.
Rome, Italy.
Food and Agriculture Organization of the United Nations (FAO), IFAD,
UNICEF, WFP, WHO (2019). The State of Food Security and
Nutrition in the World 2019. Safe guarding against economic
slowdowns and downturns. Rome, Italy.
Froese R (2006). Cube law, condition factor and weight–length
relationships: history, meta-analysis and recommendations. Journal
of Applied Ichthyology 22:241-253
Jauncey K (1982). The effect of varying dietary protein levels on growth,
food conversion, protein utilization, and body composition of juvenile
tilapia (Sarotherodon mossambicus), Aquaculture 27:43–54.
Jauncey K, Sorensen PL, Areola F (2007). A short handbook - Catfish
feed for Nigeria. CDE, Brussels.
938
Afr. J. Agric. Res.
Kaushik SJ (2000). Feed formulation, diet development and feed
technology. In Recent advances in Mediterranean aquaculture finfish
species diversification. Zaragoza: CIHEAM. pp. 43-51
Kim SS, Lee KJ (2009). Dietary protein requirement of juvenile Tiger
puffer (Takifugu rubripes). Aquaculture 285:219-222.
Kumar KG (2010). International collective in support of fish workers
(ICSF). Workshop on small indigenous freshwater fish species: Their
role in poverty alleviation, food security and conservation of
biodiversity. Central Inland Fisheries Research Institute, Barrackpore,
Kolkata, West Bengal.
Legendre M (1986). Seasonal changes in sexual maturity and fecundity,
and Hcg-induced breeding of the Catfish, Heterobranchus longifilis
Val. (Clariidae), reared in Ebrie lagoon, Ivory Coast. Aquaculture
55:201-213.
Ministry of Agriculture Animal Industry and Fisheries (MAAIF) (2004).
National Fisheries Policy for Uganda (NFP). Kampala, Uganda:
Ministry of Agriculture Animal Industry and Fisheries.
Ministry of Water and Environment (2018). The Uganda Water and
Environment Sector performance report 2018. Kampala, Uganda.
Mwangamilo JJ, Jiddawi NS (2003). Nutritional studies and
development of a practical feed for Milkfish (Chanos chanos) culture
in Zanzibar, Tanzania. Western Indian Ocean Journal of Marine
Science 2:137–146.
National Agricultural Research Organization (NARO) (2017). The
National Fisheries Resources Research Institute (NaFIRRI) Annual
Report 2016/2017.
Odulate DO, Idowu AA, Fabusoro AA, Odebiyi CO (2014). Growth
Performance of Juvenile Clarias gariepinus (Burchell, 1822) Fed
Ipomoea aquatica based diets. Journal of Fisheries and Aquatic
Science 9:468-472.
Otubusin SO, Ifili NN (2000). Growth performance of C. gariepinus fed
on plankton, frozen maggots and pelleted feed in floating hapa
system. Journal of Fish Technology 2:117-123.
Phillips M, Genschick S, Lyman AT (2015). Rural 21 Scientific world.
WorldFish. Penang, Malaysia www.rural21.com
Pouomogne V (2008). Capture-based aquaculture of Clarias catfish:
Case study of the Santchou fishers in Western Cameroon. FAO
Fisheries Technical Paper. No. 508:93-108.
Robinson EH, Li MH, Manning BB (2001). A practical guide to nutrition,
feeds and feeding of catfish (2nd ed.). Mississipi State University.
Solomon RJ, Taruwa SM (2011). The growth comparison of two
catfishes (C. Gariepinus and Heteroclarias). Nature and Science
9:138-148.
Solomon SG, Okomoda VT (2012). Growth response and aggressive
behaviour of Clarias gariepinus fingerlings reared at different
photoperiods in a water re-circulatory system. Livestock Research for
Rural Development 24:191. Retrieved December 19, 2019, from
http://www.lrrd.org/lrrd24/11/shol24191.htm.
Thilsted SH (2012). The potential of nutrient-rich small fish species in
aquaculture to improve human nutrition and health. In: Subasinghe,
R.R.; Arthur, J.R.; Bartley, D.M.; De Silva, S.S.; Halwart, M.;
Hishamunda, N.; Mohan, C.V.; Sorgeloos, P. (eds.): Farming the
waters for people and food. Proceedings of the Global Conference on
Aquaculture 2010. Phuket, Thailand, 22-25 September 2010, pp. 5773. FAO, Rome and NACA, Bangkok.
Uganda Bureau of Statistics (UBOS) (2018). Statistical abstract 2018.
Kampala, Uganda.
Uganda Demographic and Health Survey (UDSH) (2017). Key
Indicators Report for 2016. Uganda Bureau of statistics, Kampala
Uganda.
World Bank (2013). Fish to 2030: prospects for fisheries and
aquaculture. Agriculture and environmental services discussion
paper;
no.
3.
Washington
DC.
http://documents.worldbank.org/curated/en/458631468152376668/Fi
sh-to-2030-prospects-for-fisheries-and-aquaculture
Yatuha J, Kang’ombe J, Chapman L, Rutaisire J (2012). Diet and
feeding habits of the small catfish, Clarias liocephalus in wetlands of
western Uganda. African Journal of Ecology 51:385-392.
Yatuha J (2015). Feed, feeding habits and aspects of reproductive
biology of Clarias liocephalus, a potential culture species for small
holder fish farms in South Western Uganda. Ph.D thesis. Bunda
College, University of Malawi.