GROWTH PERFORMANCE OF RIVER BASED CAGE TILAPIA, OREOCHROMIS NILOTICUS (LINNAEUS, 1758) FARMING UNDER DIFFERENT STOCKING DENSITIES
Date
2017-12
Authors
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Journal ISSN
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Publisher
HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR
Abstract
This study was conducted to observed the growth performances of cage culture of tilapia
(Oreochromis niloticus) under different stocking densities through length-weight (LW)
relationship technique and condition factor (K) of O. niloticus caught from three
treatment (T1, T2 and T3) in cage culture from February to October, 2017 in the Atrai river
of Dinajpur, Bangladesh. The fish were stocked in truplicate of three treatment cage, with
stocking densities of 500,600 and 700 per cage (20ft×10ft) respectively. Fortnightly 15%
fish were collected from each cage for measuring the body weight and length. The fishes
were ranged from 5.842-33.274 cm, 7.62-33.25 cm and 7.874-32.258 cm in length, while
weight ranged 8.1-690 g, 8.3-685 g and 10.7-673 g for Treatment 1, Treatment 2 and
Treatment 3 respectively. These results showed that the growth patterns of O. niloticus
were described by the formula. Ln BW = 3.0(lnTL) -3.835, lnBW = 2.971(lnTL)-3.76 and
ln BW = 2.91(lnTL)-3.723 for Treatment 1, Treatment 2 and Treatment 3 respectively.
The value of the regression co-efficient (b) obtained for the length-weight relationships as
3.0(isometric growth), 2.971 (negative allometric) and 2.961 (negative allometric) for
Treatment (T1, T2 and T3) cage respectively. In case of O. niloticus there is not significant
different observed (P>0.05) between the slope of the three Treatment (T1, T2 and T3). The
value coefficient of determination (R2
) was, 0.931, 0.885 and 0.915 for Treatment 1,
Treatment 2 and Treatment 3 respectively. In this study, the mean value of condition
factors K was 2.24±0.51, 2.23±0.72 and 2.20±0.64 for Treatment 1, Treatment 2 and
Treatment 3 respectively. Condition factors K were greater than 1 in all Treatment
indicates that O. niloticus were in good condition and healthy and suitable for cages
culture fish. Moreover, growth parameter: asymptotic length Lα were 33.27,33.20 and
32.26 and also founds as growth coefficient k were 0.51, 0.48 and 0.41 for Treatment 1,
Treatment 2 and Treatment 3 respectively while the growth performance index, Ø as
highest (2.75) in Treatment 1 and followed by Treatment 2 (2.72) and then (2.63) in
Treatment 3 respectively. The survival rate specific growth rate production higher in
treatment 1 than other treatments. The result showed that lower stocking densities higher
growth performance in cage culture system.
Description
Bangladesh has huge water resources that are spreader all over the country in the form of
pond, lakes, beels, haors, and baors, small and large river. The climatic condition of the
country (moderate temperature, heavy rainfall during monsoon seasons) is also favorable
to support the diversified fish. The country has coastal area of about 710km along the Bay
of Bengal. The country has exclusive economic zone of about 200n. Miles. The water
body contains large variety of fish species both fresh water and marine water. There are
about 260 of freshwater fish species, 475 marine water species, 12 exotic fish species, 24
freshwater prawn, 36 marine shrimps species (DoF, 2016)
Keywords
Length-weight relationship, condition factor, growth parameter