International Journal of Aquaculture, 2016, Vol.6, No.5, 1
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14
3
Figure 1 Length – weight relationship of female
L. carinita
in
Suez Bay
Figure 2 Length – weight relationship of male
L. carinita
in
Suez Bay
The study of length - weight relationship is of paramount importance in fishery science, as it assists in
understanding the general wellbeing and growth patterns in a fish population. It opined that length - weight
relationship of fish varies depending upon the condition of life in an aquatic environment. Ideally, the regression
coefficient “b” of a fish should be very close to 3.0 (Allen, 1938), however the cube law does not hold well
throughout the life period and the weight gain in fish may not be always cube of its length gain (Rousenfell and
Everhart, 1953). (Hile, 1936; Martin, 1949) opined that the value of “b” may range between 2.5 and 4.0. (Antony,
1967) recorded the value of “b” within a range of 2.0 to 5.4. Also (a) depends on weight and it can be used as
status value (King, 2007).
The length - weight relationship for females and males of
L. carinata
showing high positive relationship with
higher R - value (0.874 5) for females than males (0.802 4), the b value for females (2.946) is not significantly
different from 3, but in males b has less value (2.569) which was significantly different from 3. Therefore, females
showing isometric growth but males of
L. carinata
are showing negative allometric growth, indicated that the
weight of fish were not too much for their length, this may be responsible for the slimmer shape of the body as it
increase body length (Jobling, 2002), this result is similar to what (Grant et al., 1977) reported on the Australian
mullet. This differs in b - values of males and females can explain by difference in length distribution of the two
sexes. The high b - value of females than males also reported in many other studies (Table 1).
Table 1 Values of length-weight relationship (a, b and R) for different species at different regions
References
a-values
b-values
R
2
or R-values
female
male
female
male
female
male
Species
(Ilkyaz et al
,
2006)
0.115
0.127
2.94
2.78
0.92
0.89
L. aurata
(Glamuzina et al, 2007)
0.003
0.014
3.27
2.85
0.95
0.95
L. ramada
(Lawson, et al
,
2010)
-4.89
-3.91
2.9
2.48
0.89
0.87
L. falcipinnis
(Balik et al, 2011)
0.006
0.006
3.2
3.1
0.97
0.96
L. saliens
(De Oliveira et al, 2011)
0.00004
0.00005
2.75
2.7
0.92
0.95
M. curema
(Hashemi et al
,
2013)
0.011
0.024
3
2.76
0.78
0.72
L. klunzinger
i
(El-Ganainy et al
,
2014)
0.0055
2.869
0.919
L. carinata
0.016
2.847
0.75
L. ramada
(Mohammed et al, 2016)
0.014
2.892
0.74
Mugil cephalus
Present study
0.012
0.034
2.94
2.56
0.87
0.8
L. carinata
The obtained a, b and R - values in the present study are more or less similar to that mentioned in the previous
table; (Le Cren, 1951) pointed out that the variation in “b” value is due to environmental factors, season, food
availability, sex, life stage and other physiological factors.
3.2 Length frequency distribution for both sexes
The length frequency of male and female
L. carinata
was no largely differ from their length classes. The length
