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Biometric analysis of oil sardine Sardinella longiceps Valenceinnes, 1847 (Clupeiformes:
Clupeidae) along Ratnagiri coast of Maharashtra.
Tasaduq H. Shah, S.K. Chakraborty, A.K. Jaiswar, Tarkeshwar Kumar, K.M. Sandhya & R.K.
Sadawarte.
Central Institute of Fisheries Education, Versova, Andheri (West), Mumbai-400 061, Maharashtra, India.
[E-mail: tasaduqs@gmail.com]
Received; revised
Length-weight relationship, morphometric and meristic characters of oil sardine Sardinella longiceps
Valenceinnes, 1847 from Ratnagiri waters off Maharashtra, India were investigated by studying 917
specimens (368 males, 404 females and 145 indeterminates). Fourteen morphometric characters studied
exhibited high level of interdependence (r= 0.81 to 0.99). Based on the studies conducted on meristic
characters, the fin formula of S. longiceps can be written as B5-7 P14-16 V8-9 D14-18 C16-24 A11-17. Length-
weight relationship was established as W = 0.000066L2.604
for males, W = 0.000056L2.638
for females and
W = 0.000054L2.645
for pooled data, indicating negative allometric growth in S. longiceps. Coefficient of
correlation (r) for the length-weight relationship was estimated at 0.721, 0.739 and 0.740 for the males,
females and pooled data respectively.
[Keywords: Sardinella longiceps, morphometry, meristics, length-weight relationship, Ratnagiri.]
Introduction
The clupeoids comprise a major group among the pelagic resource of India contributing about a
third of the marine fish production. They are represented in Indian waters by about 106 species belonging
to groups sardines (Sardinella spp.), anchovies (Thrissocles spp.), white baits (Anchoviella spp.), rainbow
sardine (Dussumiera spp.), shads (Hilsa spp.), herrings (Chirocentrus spp.), etc. Sardines form the most
important group among clupeoids and are represented by 15 species, namely oil sardine, Sardinella
longiceps and 14 species of lesser sardines represented mainly by Sardinella fimbriata, S. gibbosa, S.
albella, S. sirm, S. dayi, S. clupeoides, S. sindensis, S. melanura, etc.
Oil sardine, Sardinella longiceps Valenciennes 1847 is a major neretic pelagic fishery resource
of India and ranks as a very valuable commercial fish owing to its food value and industrial use. Previous
investigations on the morphometric and meristic characters of Sardinella longiceps are those by
Valenciennes1, Day
2, Gunther
3, Hornell and Nayudu
4, Devanesan and Chidambaram
5, Chan
6, Whitehead
7,
Antony Raja8, Menezes
9 and Fisher and Bianchi
10. Studies on the length-weight relationship of S.
longiceps have been carried out by Dhulkhed11
, Antony Raja12
, Annigeri13
, Kurup et al14
, Gopal and
2
Savaria15
, Annigeri et al16
, Kasim et al17
, Deshmukh et al18
, Abdussamad et al19
, Al-Jufaili20
. As there is
no previous report on the morpho-meristic characteristics of S. longiceps from Ratnagiri waters, an
attempt has been made to investigate the morphometric, meristic and length-weight relationship of S.
longiceps from Ratnagiri waters.
Materials and Methods
A total of 917 specimens of S. longiceps in the length range of 114 to 212 mm and weight range
of 11.52 to 86.82 g were collected at random on monthly basis from Mirkarwada landing centre of
Ratnagiri, Maharashtra, India (Figure 1) during October, 2010 to May, 2012.
Morphometric characters were recorded by using fish measuring board, divider and digital
vernier caliper for accuracy to the nearest mm. Standard procedure as described by Lagler et al21
,
Laevastu22
, Lowe-McConnel23
, Dwivedi and Menezes24
and Grant and Spain25
were followed.
Morphometric characters studied were total length (TL), standard length (SL), pre-dorsal length (PDL),
pre-pectoral length (PPL), pre-ventral length (PVL), pre-anal length (PAL), head length (HL), snout
length (SnL), inter-orbital length (IOL), post-orbital length (POL), body depth (BD), eye diameter (ED),
pectoral fin length (PFL) and caudal fin length (CFL). Meristic characteristics studied in the present
investigation include number of dorsal fin rays, pectoral fin rays, ventral fin rays, anal fin rays, caudal fin
rays, branchiostegal rays and the number of gill rakers on the lower limb of the first gill arch taken from
the left side of the fish.
Relationships between the various body measurements to the total length and head length have
been established. Scattergrams of various morphometric characters were plotted and then linear
regression equation was fitted using least square method described by Laevastu22
and Snedecor and
Cochran26
. Relationships were represented by the equation:
Y = a + b x
Where, “y” is a dependent variable, “x” is an independent variable, “a” is a constant (intercept) and “b” is
the regression coefficient (slope). The coefficient of correlation (r) was computed to know the degree of
linear relationship between the two variables.
The value of “a” is determined by the following formula:
a
The value of “b” is determined by:
b= [nΣxy–ΣxΣy] / [nΣx2 – (Σx)
2]
3
Correlation coefficient (r) is usually calculated to express the degree of linear association or
interdependence of two variables as:
r = [nΣxy–ΣxΣy] / √ [nΣx2-(Σx)
2][nΣy
2-(Σy)
2]
Study of length-weight relationship was based on 772 specimens of S. longiceps comprising of
368 males (128 to 205 mm in total length and 14.36 to 68.08 g in total weight) and 404 females (133 to
212 mm in total length and 17.51 to 86.82 g in total weight). Total length (TL) was measured to the
nearest mm using measuring board and weight was noted to the nearest 0.01 g accuracy in an electronic
balance.
Length-weight relationship was established separately for males and females using the formula
by Le Cren27
:
W = a L b
The relationship can be expressed in the logarithmic form as:
Log W = Log a + b Log L
Where, “W” is the weight of fish in gram (g), “L” is the length of fish in millimeters (mm), “a” is the
intercept and “b” is the regression coefficient.
Analysis of covariance was done to determine variation in ‘b’ values among the sexes at 1% and
5% level of significance by following Snedecor and Cochran26
. To test “b” value against the value of “3”,
student’s t-test was employed to predict any significant deviation. The t-statistic was calculated as
follows:
Hypothesis given is,
H0: Growth is isometric i.e. H0: b = 3
H1: Growth is allometric i.e. H1: b ≠ 3
The t statistics used are given by:
t = │b-3│/Sb
Where, Sb= Standard error of “b” and t has (n-2) degrees of freedom.
Sb = √ (1/ (n-2))*[(Sy/Sx)2-b
2]
4
Where, “Sx” and “Sy” are the standard deviations of x and y respectively. The t-value was compared with
t-table value for (n-2) degrees of freedom at 1% and 5% significance level.
Results
Morphometrics and meristics
Analysis of the data revealed a maximum co-efficient of variation in inter-orbital length
(13.10%) followed by caudal fin length (10.95%) and body depth (10.75%). Lowest co-efficient of
variation was recorded in eye diameter (8.83%). Results reveal a simple straight line regression of
standard length, pre-dorsal length, pre-pectoral length, pre-ventral length, pre-anal length, head length,
body depth, pectoral fin length and caudal fin length against total length as well as of snout length, inter-
orbital length, post-orbital length and eye diameter against head length. Co-efficient of correlation “r” of
total length against other morphometric characters ranged from 0.83 (against body depth) to 0.99 (against
standard length). Co-efficient of correlation “r” of head length against other morphometric characters
ranged from 0.81 (against eye diameter) to 0.91 (against post-orbital length). The “r” values obtained
indicate that the morphometric characters under study are highly correlated to each other. The statistical
estimates like range, mean, median, standard error, standard deviation and co-efficient of variation of
various morphometric characters are presented in table 1. Scattergrams for the relationships between the
morphometric characters are presented in figure 2 and figure 3. Values of intercept “a”, slope “b” and
correlation “r” are depicted in table 2.
An analysis of meristic characters of 287 specimens indicated that the species possesses 14 to 16
soft rays in its pectoral fin, 8 to 9 soft rays in its ventral fin, 14 to 18 soft rays in its dorsal fin, 16 to 24
soft rays in its caudal fin, 11 to 17 soft rays in its anal fin and 5 to 7 branchiostegal rays. Number of gill
rakers on the lower limb of the first gill arch of the left side varied from 98 to 245. Co-efficient of
variation of gill rakers was the maximum (12.24) of all the meristic characters studied followed by caudal
fin rays (8.74) and anal fin rays (8.24). Range, mean, mode, median, standard error, standard deviation
and Co-efficient of variation for six meristic characteristics namely, pectoral fin rays, ventral fin rays,
dorsal fin rays, caudal fin rays, anal fin rays, branchiostegal rays and gill rakers are presented in table 3.
From the above studies, the fin formula for S. longiceps of Ratnagiri waters can be written as:
B5-7 P14-16 V8-9 D14-18 C16-24 A11-17
5
Length-weight relationship
Length-weight relationship was established as:
Male: W = 0.000066L2.604
and
Female: W = 0.000056L2.638
Same is expressed logarithmically as:
Male: LogW = -4.179 + 2.604 LogL (R2 = 0.721)
Female: LogW = -4.248 + 2.638 LogL (R2 = 0.739)
Scattergrams of power relation and logarithmic relation of length and weight has been plotted
separately for males (Figure 4), females (Figure 5) and pooled (Figure 6). Analysis of co-variance (Table
5) indicated that the regression of co-efficient of length-weight relationship of both the sexes show no
significant variation at 1% or 5% level. Hence, the length-weight data of males and females was pooled
together and length-weight relationship was established as:
W = 0.000054L2.645
Same is expressed logarithmically as:
LogW = -4.267 + 2.645 LogL (R2 = 0.74)
The calculated “t” value for the student’s t-test was found to be significant at 1% and 5% level.
Discussion
A comparison of the meristic characters of S. longiceps in the present study with some
earlier works is presented in table 4. An analysis of the results obtained in the study indicates that there is
no significant variation in the morphometric and meristic characteristics within the population. Slight
variations recorded in the morphometric and meristic characters in the present study when compared to
earlier reports may be a result of genetical components28
or environmental components like temperature,
salinity, food availability, etc.29-33
. Range, mean, median, standard error, standard deviation and
6
coefficient of variation of the morphometric characters indicate high degree of homogeneity within the
population of S. longiceps along the Ratnagiri coast.
Analysis of results for length-weight relationship indicates negative allometric growth for S.
longiceps. The earlier investigations on length-weight relationship of S. longiceps include those of
Dhulkhed11
from Mangalore, Antony Raja12
from Calicut region, Annigeri13
from Karwar, Kurup et al14
from Calicut, Gopal and Savaria15
from Saurashtra coast, Annigeri et al16
from west coast of India, Rohit
and Bhat34
from Mangalore-Malpe, Kasim et al17
from Cuddalore coast, Deshmukh et al18
from Ratnagiri,
Abdussamad et al19
from east coast of India and Al-Jufaili20
from Al-Seeb area, Oman. These authors
have reported both isometric and allometric growth pattern for S. longiceps in their respective studies
(Table 6). The value of regression coefficient (b=2.64) obtained in the present study for the pooled data is
comparable with those of Kurup et al14
(b=2.92), Gopal and Savaria15
(b=2.68), Rohit and Bhat34
(b=2.86)
and Deshmukh et al18
(b=2.52).
Values of the exponent ‘b’ provide information on fish growth. When b=3, increase in weight is
isometric i.e., length increases in equal proportions with body weight. When the value of b is other than 3,
weight increase is said to be allometric (positive if b>3 and negative if b<3). The ‘b’ value above 3
indicates that the fish become wider or deeper as they grow, while an exponent below 3 indicates they
become more slender. In the present investigation, b<3 indicates that on Ratnagiri coast the fish is
becoming slender with increase in growth.
Different values of exponent ‘b’ in S. longiceps obtained by some workers may be attributed to
the geographical and ecological differences which lead to variations in water quality parameters and food
availability, thereby affecting the growth of fish35
. Significant differences between the values of exponent
‘b’ of the length-weight relationship has been even reported between seasons (spring and summer) for
sardine on the Portuguese west coast36
. Some authors have reported values of b>3 indicating positive
allometric growth in S. longiceps11, 13, 16, 17
. The results may be influenced by the year classes of the
specimens used for arriving at the length-weight relationship as the representation of younger fishes in the
sample results in a higher value of ‘b’. On the other hand, predominance of older or mature groups of
fishes could significantly reduce ‘b’ value. This may be one of the reasons behind the less-than-3 value
obtained for ‘b’ in the present investigation as fish below 114 mm was not recorded in the catches during
the 20 months of observation.
Acknowledgements
7
Authors are grateful to Dr. W. S. Lakra, Director, Central Institute of Fisheries Education
(CIFE), Mumbai and to Indian Council of Agricultural Research (ICAR), New Delhi for providing
necessary facilities for carrying out this research work.
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11
Table 1: Statistical estimates of various morphometric characters in S. longiceps.
Range (mm)
Statistical estimates Min Max
Mean
(mm)
Median
(mm)
Standard
error
Standard
deviation
Coefficient
of
Variation
(%)
Total Length 114.00 212.00 174.27 177.00 0.55 16.80 9.64
Standard Length 94.00 192.00 141.89 144.00 0.45 13.58 9.57
Pre-dorsal Length 43.00 84.00 69.46 71.00 0.23 6.85 9.87
Pre-pectoral Length 26.00 54.00 43.06 44.00 0.13 4.08 9.47
Pre-ventral Length 50.00 100.00 80.65 82.00 0.27 8.20 10.17
Pre-anal Length 73.00 145.00 113.87 116.00 0.38 11.51 10.10
Head Length 27.00 56.00 45.99 47.00 0.14 4.38 9.51
Snout Length 7.00 15.00 12.31 12.50 0.04 1.32 10.69
Inter-orbital Length 5.01 12.00 8.45 8.53 0.04 1.11 13.10
Post-orbital Length 15.00 31.00 25.31 26.00 0.09 2.64 10.42
Body depth 14.00 42.00 31.84 32.00 0.11 3.42 10.75
Eye diameter 5.84 10.63 8.84 8.96 0.03 0.78 8.83
Pectoral fin Length 12.00 36.00 23.23 24.00 0.08 2.33 10.05
Caudal fin Length 20.00 47.00 32.68 33.00 0.56 3.58 10.95
12
Table 2: Relationship between different morphometric characters in S. longiceps.
S.
No. Morphometric character
Intercept
(a)
Slope
(b) Y = a + bX
Correlation
(r)
1. Total Length & Standard Length 2.2282 0.8002 Y = 2.2282 + 0.8002X 0.99
2. Total Length & Pre-dorsal Length 0.5188 0.3956 Y = 0.5188 + 0.3956X 0.97
3. Total Length & Pre-pectoral
Length 5.7319 0.2142 Y = 5.7319 + 0.2142X 0.88
4. Total Length & Pre-ventral Length 1.0291 0.4569 Y = 1.0291 + 0.4569X 0.94
5. Total Length & Pre-anal Length -3.0443 0.6709 Y = -3.0443 + 0.6709X 0.98
6. Total Length & Head Length 4.9642 0.2354 Y = 4.9642 + 0.2354X 0.90
7. Total Length & Body Depth 2.2610 0.1697 Y = 2.2610 + 0.1697X 0.83
8. Total Length & Pectoral Fin
Length 1.9678 0.1220 Y = 1.9678 + 0.1220X 0.89
9. Total Length & Caudal Fin Length -0.9148 0.1929 Y = -0.9148 + 0.1929X 0.91
10. Head Length & Snout Length -0.1912 0.2718 Y = -0.1912 + 0.2718X 0.90
11. Head Length & Inter-orbital
Length -1.1371 0.2084 Y = -1.1371 + 0.2084X 0.82
12. Head Length & Pre-orbital Length 0.0771 0.5487 Y = 0.0771 + 0.5487X 0.91
13. Head Length & Eye Diameter 2.1608 0.1452 Y = 2.1608 + 0.1452X 0.81
13
Table 3: Statistical estimates of various meristic characters in S. longiceps.
Statistical Estimate Range Mean Mode Median
Standard
Error
Standard
Deviation
Co-efficient
of Variation
(%)
Pectoral fin rays 14 - 16 15.28 15 15 0.03 0.54 3.54
Ventral fin rays 8 - 9 8.98 9 9 0.01 0.13 1.46
Dorsal fin rays 14 - 18 16.04 16 16 0.03 0.74 4.61
Caudal fin rays 16 - 24 19.15 18 18 0.10 1.67 8.74
Anal fin rays 11 - 17 14.16 15 14 0.07 1.17 8.24
Branchiostegal rays 5 - 7 6.02 6 6 0.01 0.16 2.58
Gill rakers 98 - 245 181.40 186 184 1.52 25.83 14.24
14
Table 4: Comparison of meristics characters of S. longiceps with works carried out by other
investigators.
Authors Pectoral
fin rays
Ventral
fin rays
Dorsal
fin rays
Caudal
fin rays
Anal
fin rays
Branchi-
ostegal
rays
Gill
rakers
Day2 17 9 16-17 17 14-16 6 -
Gunther3 - - 16 - 16 - -
Weber and Beaufort37
15-16 8-9 16-18 - 13-16 6 Approx.
120
Li38
- - 16-18 - 14-16 - 180-250
Chan6 - - 15-18 - 15-16 - 145-258
Whitehead7 - - 17-19 - 15-16 - 180-250
Antony Raja39
15-16 9 15-17 - 13-16 - 187-268
Nair40
- 9 16-18 - 14-16 - 180-250
Menezes9 13-16 9 14-17 - 12-15 - -
Fisher and Bianchi10
- 9 - - - - 150-255
Talwar and Kacker41
- 9 13-15 - 12-15 - 150-250
Lazarus42
16 9 14 36 13 - -
Al-Baharna43
- 9 - - < 30 6-7 > 130
Present study 14-16 8-9 14-18 16-24 11-17 5-7 98-245
15
Figure 2: Relationship of different morphometric characters with total length in S. longiceps.
SL: y = 0.800x + 2.228
R² = 0.985
PDL: y = 0.395x + 0.518
R² = 0.940
PPL: y = 0.214x + 5.731
R² = 0.779
PVL: y = 0.456x + 1.029
R² = 0.876
PAL: y = 0.670x - 3.044
R² = 0.960
HL: y = 0.235x + 4.964
R² = 0.817
BD: y = 0.169x + 2.261
R² = 0.694
PFL: y = 0.122x + 1.967
R² = 0.796
CFL: y = 0.192x - 0.914
R² = 0.823
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200 250
Va
ria
ble
s (m
m)
Total Length (mm)
SL
PAL
PVL
PDL
HL
PFL
CFL
PPL
BD
Figure 3: Relationship of different morphometric characters with head length in S. longiceps.
SnL: y = 0.271x - 0.191
R² = 0.817
IOL: y = 0.208x - 1.137
R² = 0.678
POL: y = 0.548x + 0.077
R² = 0.828
ED: y = 0.145x + 2.160
R² = 0.663
0
5
10
15
20
25
30
35
0 10 20 30 40 50 60
Va
ria
ble
s (m
m)
Head Length (mm)
POL
SnL
IOL
ED
16
Figure 4: Length-weight relationship in S. longiceps (Male).
Figure 5: Length-weight relationship in S. longiceps (Female).
Figure 6: Length-weight relationship in S. longiceps (Pooled).
17
Table 5: Analysis of covariance for testing length-weight relationship of males and females.
Raw Sums Sex
Number ∑x ∑y ∑x² ∑y² ∑xy
Male 368 825.962 612.985 1854.113 1023.606 1376.527
Female 404 911.012 686.879 2054.672 1171.205 1549.844
Pooled 772 1736.974 1299.864 3908.785 2194.810 2926.371
Deviations from regression
Source d.f. ssx ssy spxy Reg.coef d.f. S.S. M.S F
Within
Males 367 1.434825 13.48802 3.736931 2.604451 366 3.755369 0.010261
Females 403 1.90305 17.90813 5.020329 2.638044 402 4.664282 0.011603
768 8.419651 0.010963
Pooled
W
770 3.337875 31.39615 8.75726 2.623603 769 8.420574 0.01095
Difference between slopes 1 0.000923 0.000923 0.084308
n.s.
Between
B
W+B 771 3.450798 32.60963 9.127436 770 8.467366
Between adjusted means 1 0.046792 0.046792 4.273228
*
n.s. : not significant at 5% level (P>0.05)
* : significant at 5% level (P>0.05)
18
Table 6: Estimates of intercept (a), slope (b) and correlation coefficient (r) for length-weight
relationship of S. longiceps obtained from previous studies.
Author/s Location Sex No. of
Obser-
vations
Intercept
(a)
Slope
(b)
Correlation
coefficient
(r)
Indeterminate 49 -7.6451 3.6169
Female 250 -6.3420 3.2665
Male 194 -6.7010 3.1086
Dhulkhed11
Mangalore,
India
Combined 493 -6.4662 3.2123
Male -6.5548 3.1729
Female -7.8442 3.5034
Unsexed -5.1305 2.8762
Annigeri13
Karwar, India
Average -6.6172 3.1890
Kurup et al14
Calicut, India Combined 1335 0.0000135 2.9268
Male 54 -4.514 2.744 0.9582
Female 62 -4.237 2.617 0.9531
Gopal and Savaria15
Saurashtra
Coast, india
Combined 116 -4.378 2.682 0.9557
Annigeri et al16
West coast of
India
Combined 499 0.00000347 3.1635
Rohit and Bhat34
Mangalore-
Malpe
Combined 0.01189 2.86
Male 0.000001518 3.3498
Female 0.000002705 3.2344
Kasim et al17
Cuddalore
coast, India
Unsexed 0.000002366 3.2613
Male 381 0.0350 2.4918
Female 440 0.0536 2.3410
Indeterminate 178 0.0200 2.7021
Deshmukh et al18
Ratnagiri, India
Combined 999 0.0321 2.5225
Abdussamad et al19
East coast of
India
Combined 624 0.0126 2.903
Male 517 0.00000907 3.0
Female 826 0.00000813 3.0
Al-Jufaili20
Al-Seeb, Oman
Combined 1343 0.00000843 3.0
19
Male 368 0.000066 2.604 0.721
Female 404 0.000056 2.638 0.739
Present study Ratnagiri, India
Combined 772 0.000054 2.645 0.740
20
Figure 1: Location of the sampling area in the Arabian Sea along Ratnagiri Coast off Maharashtra
India.
INDIA
MUMBAI
RATNAGIRI
GOA
KARACHI
ARABIAN
SEA
GULF OF
OMAN
OMAN
RATNAGIRI
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