International Journal of Marine Science 2015, Vol.5, No.30, 1-5
3
Table 1 Statistical description and LWR parameters obtained for 10 coral reef associated fishes length parameters (length ranges in
cm (minimum and maximum), mean and standard deviation (SD)), weight parameters (weight ranges (minimum and maximum),
mean and standard deviation (SD)), parameters of the LWR (N: number of specimens sampled, a: intercept, b: slope and r
2
coefficient
of determination) and type of growth (isometric (I) or allometric (A), (positive or negative))
Species
N
Length (cm)
Weight (g)
Parameters of LWR
Growth type
Min
-
max Mean ±S.D. Min
-
max
Mean ±S.D. a
b
r
2*
Siganus canaliculatus
204 11.2
-
27.4 18.6±4.1
16.1
-
186.4 97.9±55.0
0.0172 2.91 0.95
-
A
Siganus javus
188 9.2
-
22.6 14.9±2.9
16.14
-
165.4 69.4±40.2
0.0308 2.81 0.94
-
A
Trachinocephalus myops
228 13.2
-
27.9 19.9±3.0
19.2
-
187.2 79.4±38.4
0.0055 3.17 0.95 + A
Lutjanus russellii
176 12.1
-
25.6 18.4±3.9
25
-
198.6
98.4±58.0
0.0176 2.91 0.98
-
A
Lutjanus fulviflamma
71
11.3
-
25.7 18.6±4.8
17
-
205.2
106.0±68.6
0.0151 2.96 0.97
-
A
Acanthurus tristis
166 9.7
-
22.8 14.6±3.3
16.1
-
166.2 64.0±41.6
0.0305 2.80 0.97
-
A
Upeneus vittatus
80
11
-
20.7
15.5±2.6
20.3
-
160
64.2±37.8
0.0088 3.20 0.98 + A
Scolopsis vosmeri
50
11.3
-
17.5 14.1±1.8
28.5
-
96.4
60.6±21.8
0.0285 2.87 0.96
-
A
Scatophagus argus
30
9.2
-
14.8 11.4±1.5
22.6
-
78.6
44.8±17.2
0.0562 2.71 0.94
-
A
Epinephelus coioides
70
18.4
-
31.2 24.5±3.5
86.4
-
373.1 212.7±89.4
0.0132 3.00 0.93 I
Note: *Refer to the log W = log a + b log L regression
had negative allometric (b<3), one species had
isometric (b=3) and two species had positive
allometric (b>3) growth.
3 Discussion
The b values for all the ten species of fishes fall
between 2.5 to 3.5 this will agree with the suggestion
of Carlander (1969) and Froese (2006). The values of
b< 2.5 or >3.5 are mostly caused by samples with
narrow size ranges Carlander (1977). The b values
reported by Letourneur et al. (1998) for
Lutjanus
fulviflamma
(2.906),
Lutjanus russellii
(2.907),
Epinephelus coioides
(3.084) and
Upeneus vittatus
(3.309) in New Caledonia agree with values presented
here, but the value of
Scatophagus argus
(2.922) and
Siganus canaliculatus
(3.010) was slightly higher
when compared to the present study. Jayasankar (1990)
and Gandhi
et al. (2013) reported almost similar b
values for
Siganus canaliculatus
(2.819) and
Scatophagus argus
(2.842) in Gulf of Mannar. Shoba
Joe and Gomathy (2007) also reported more or less
similar b value (3.047) for
Trachinocephalus myops
at
Chennai. These differences could be due
to
difference
in environmental
and
biological
parameters
and
also
to
the
type
of
the
sampling,
like
size
ranges,
number
of individuals
collected and period of collection.
In
addition the LWR are
not
stable
for fishes from
various regions,
it may vary
in
relation
to their
environmental factors
like
temperature, salinity,
food
(quality, quantity and
size),
habitat
and
gonad maturity,
spawning
period,
season, sex, absence of juveniles,
health, fishing
time and fishing
gears
(Ricker, 1973;
Safran, 1992; Froese, 2006).
According to Petrakis and Stergiou (1995), the use of
these length-weight relationships must be thoroughly
restricted to the size ranges applied in the estimation
of the linear regression parameters. For this reason, it
is risky to extrapolate data to fish larvae, juveniles or
immature stages (Begenal and Tesch, 1978; Safran,
1992 and Pepin, 1995). The length-weight relationship
parameters may differ considerably due to biological
and environmental situation or geographical, temporal
and sampling factor (Bagenal and Tesch, 1978; Froese,
2006).
Regarding the growth type most of the fishes
showing negative allometry it points out that growth
prolong throughout the life span of fish but growth
rate decreasing with age. This will prove that growth
was disproportionately slow.
From these ten species there is no record of LWR for
Scolopsis vosmeri
in FishBase, hence this study
provides the first reference on LWR for this species
(Froese and Pauly, 2015). Similarly to the best of our
knowledge there is no information currently existing
on the LWR for
Acanthurus tristis, Lutjanus russellii
and
Lutjanus fulviflamma
in Indian waters.
4 Conclusion
In spite of the existence of various studies regarding
many aspects of fisheries from Indian waters, the
information available on length-weight relationship is
scattered and frequently limited to the most common
