International Journal of Aquaculture, 2013, Vol.3, No.7, 30
-
34
http://ija.sophiapublisher.com
30
Research Report Open Access
Comparative Growth Performance of Mono-Sex and Mixed-Sex Nile Tilapia
(
Oreochromis niloticus L.
)
in Pond Culture System at Sebeta, Ethiopian
Adamneh Dagne
,
Fasil Degefu
,
and Aschalew Lakew
National Fisheries and Other Aquatic Life Research Center, Sebeta-Ethiopia, P.O.Box 64, Sebeta, Ethiopia
Corresponding author email:
adamnehdet@gmail.com
;
Authors
International Journal of Aquaculture, 2013, Vol.3, No.7 doi: 10.5376/ija.2013.03.0007
Received: 1 Mar., 2013
Accepted: 14 Mar., 2013
Published: 7 Apr., 2013
Copyright © 2013
Dagne. This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Dagne, 2013, Comparative Growth Performance of Mono-Sex and Mixed-Sex Nile Tilapia (
Oreochromis niloticus L.
)
in Pond Culture System at Sebeta, Ethiopian,
International Journal of Aquaculture, Vol.3, No.7 30-34 (doi: 10.5376/ija.2013. 03.0007)
Abstract
Comparative growth performance of hand-sexed male mono-sex and mixed-sex Nile tilapia (
Oreochromis niloticus
)
was
conducted in six earthen ponds (200 m
2
each) in semi-intensive culture system. Experimental ponds were stocked at a stocking
density of 2 fish/m
2
.
Fish were cultured for a period of 240 days and fed at a daily rate of 5% of fish body weight. The results of the
experiment showed that male mono-sex tilapia showed significantly higher (P<0.05) growth rate (weight, length, DWG, SGR) than
mixed-sex group. Generally, male mono-sex fishes reached a larger final individual size (176.20±18.01) g than mixed-sex
((108.20
±15.4) g, P<0.05). This difference was more pronounced after the 6
th
month during the culture period as the later started
reproduction early in the production cycle. Analysis on the economic data indicated that both treatments showed positive net return
for the culture periods of 6 months, 7 months and 8 months. However, there was a difference in attaining the optimum net return in
culturing
Oreochromis niloticus
as male mono-sex and mixed-sex. The male mono-sex group attained its optimum net return after 6
months of culture periods, while the mixed-sex group attained after 8 months. Therefore, culturing for extra two months in the later
case showed a 32% decline from the optimum net return. Hence growing male mono-sex
Oreochromis niloticus
for 6 months is
profitable under Sebeta, Ethiopia condition.
Keywords
Tilapia farming; Pond culture; Mono-sex; Mixed-sex; Wheat bran
Abbreviations
NFALRC: National Fisheries and Other Aquatic Life
Research Center; EIAR: Ethiopian Institute of Agricultural
Research; DO: Dissolved Oxygen concentration;
TW: Total weight of the fish; TL: Total length of the
fish; FCR: Food conversion Ratio; DWG: Daily
weight gain; SGR: specific growth rate; Eth. Birr =
Ethiopian currency.
Introduction
Tilapia have been successfully farmed under a wide
range of environmental conditions and are important
group of cultured fish species in many parts of the
world, particularly in developing countries (Bentsen
et al., 1998; Gjedrem, 2005; Pillay and Kutty, 2005;
El-Sayed, 2006) . They are considered to be hardy,
rapid in growth with high food conversion ratio, easy
breeding under captivity, high fecundity and generally
resistant to many diseases. These characteristics
make tilapia suitable for culture in most developing
countries (El-Sayed, 2006). Among the tilapia,
Oreochromis niloticus
was found to be suitable for
semi-intensive culture system because of its ability
to utilize a wide range of feed
stuff
originating from
plants and/or animals (Liti et al, 2005). Moreover,
tilapia grows and matures at younger age under
captivity, contrasting to the natural system (Balarin
and Hatton, 1979; Lowe-McConnel, 1982) and
reproduces in a wide range of environmental
conditions and tolerates stress induced by handling
(
Tsadik and Bart, 2007; Chakraborty et al., 2011).
However, their breeding habit has undesirable
consequences. Some of the major problems associated
with the reproductive efficiency of
Oreochromis
niloticus
are prolific reproduction and stunted
growth in pond culture system (Phelps and Popma,
2000).
Within a few months of culture period, the
pond gets packed with various sizes of fishes and
later due to overpopulation, the growth of fish gets
slow and the fish farmers get virtually no revenue.
There exist a number of methods to control
reproduction in a mixed-sex population of
Oreochromis
niloticus
.
One of these methods is the rearing of