Morphometric and meristic variability in butis koilomatodon (gobiiformes: eleotridae) in estuarine and coastal areas of the Mekong delta

Vietnam Journal 
of Agricultural 
Sciences 
ISSN 2588-1299 VJAS 2020; 3(4): 806-816 
https://doi.org/10.31817/vjas.2020.3.4.04 
806 Vietnam Journal of Agricultural Sciences 
Received: June 8, 2020 
Accepted: October 28, 2020 
Correspondence to 
dmquang@mku.edu.vn 
Morphometric and Meristic Variability in 
Butis koilomatodon (Gobiiformes: 
Eleotridae) in Estuarine and Coastal Areas 
of the Mekong Delta 
Lam Thi Huyen Tran1,2 & Dinh Minh Quang3 
1Biotechnology Research and Development Institute, Can Tho University, Can Tho 
900000, Vietnam 
2Faculty of Agriculture and Fishery, University of Cuu Long, Vinh Long 890000, Vietnam 
3Department of Biology, School of Education, Can Tho University, Can Tho 900000, 
Vietnam 
Abstract 
The study aimed to investigate morphometric and meristic variability 
in the mud sleeper Butis koilomatodon (Bleeker, 1849) in the Mekong 
Delta. This species is a commercial fish species with a small-size and 
is mainly distributed in some coastal areas from Tra Vinh to Ca Mau 
provinces. In the present research, the parameters of morphometry 
and measurement, including the head length, body depth, eye 
diameter, distance of the two eyes, and the interrelationships among 
the morphometric variables, were determined. The results revealed 
that the total length and weight of the fish changed by sex, season, 
habitat, and the interaction between the seasons and habitats. 
Likewise, the meristic criteria were different between males and 
females, and the dry and wet seasons, but not by their interactions. 
The growth rate of males was faster than females. The outcomes also 
showed that the body size of this species was larger in the dry season 
and the largest fish were found in Duyen Hai and Tra Vinh provinces. 
The Findings would be useful not only for further effects of 
environmental factors on morphology but also for comparisons 
between congeners Butis morphologically. 
Keywords 
Measurement, meristic criteria, morphometry, the growth rate, the 
mud sleeper 
Introduction 
Morphometric and meristic characters have played a crucial role 
in identifying fish stocks and establishing the evolutionary linkages 
between ancient and modern fish fauna (Turan, 2004). In fisheries 
biology, morphometric characteristics have been used to estimate the 
percentage of fish harvested from length-weight data, determine the 
effects of environmental improvement, and regulate fisheries 
Lam Thi Huyen Tran & Dinh Minh Quang (2020) 
https://vjas.vnua.edu.vn/ 807 
(Ibáñez-Aguirre et al., 2006). In classification, 
this information has been useful to classify fish 
(Nelson et al., 2016) and measure differences and 
relationships among congeners (Turan et al., 
2006). Besides, they have also been used to study 
variations due to environmental factors (Hossain 
et al., 2009). Sandlund et al. (1992) noted that the 
morphological characteristics of fish populations 
like body coloration, meristic characteristics, 
growth, size, and age at sexual maturity could 
differ in different habitats. Morphological 
characteristics may be the result of evolution 
over time to adapt to natural selective pressures, 
genetic modifications, food availability, habitat 
competition, or even simple coincidence (Burns 
& Sidlauskas, 2019; Thacker & Gkenas, 2019). 
Butis koilomatodon (Bleeker, 1849) belongs 
to the family Eleotridae, order Gobiiformes, and 
is found along the Indo-Western Pacific region as 
a native species (Dawson, 1973). However, it is 
considered an invasive species in northeastern 
Brazil, competing with other native gobies for 
food and habitat (Macieira et al., 2012; 
GuimarãEs et al., 2017). This goby is a 
carnivore, and its main food items are 
crustaceans and small fish (Froese and Pauly, 
2000). This mud goby usually dwells in estuaries 
and mangrove creeks with salinity from 3.8‰ to 
37.0‰ (Contente et al., 2016). In Vietnam, B. 
koilomatodon is found in the Mekong Delta 
(Rainboth, 1996; Tran et al., 2013), especially in 
coastal areas. Because of its nutritional value, 
good flavor, and firm texture, the economic value 
of this fish is relatively high. Nevertheless, recent 
studies on the morphological characters of B. 
koilomatodon have been fragmented and 
insufficient (Soares et al., 2012; Contente et al., 
2016; GuimarãEs et al., 2017). Hence, this 
research aims to fill the knowledge gaps about 
the morphometric and meristic parameters of this 
species according to gender, season, and regions 
of several Vietnamese provinces, namely Duyen 
Hai (Tra Vinh); Cu Lao Dung and Tran De (Soc 
Trang); Hoa Binh and Dong Hai (Bac Lieu); and 
Dam Doi (Ca Mau). 
Materials and Methods 
Study sites 
Fish samples were collected from 04/2019 to 
03/2020 in six different sites along estuarine 
regions, namely Duyen Hai, Tra Vinh (DHTV, 
9°41'18.6"N 106°30'35.8"E); Cu Lao Dung 
(CLDST, 9°33'20.1"N 106°16'57.9"E);  ... oilomatodon did not depend on the 
interaction of gender × season (F = 0.145, P> 
0.05, Figure 8) or gender × site (F = 1.136, P> 
0.01) but were impacted by the interaction 
between season and site (F = 5.214, P< 0.01, 
Figure 9). This revealed that mud sleepers have 
different growth depending on the different kinds 
of habitats and seasons. 
Meristic variation 
Table 3 shows the meristic parameters ED, 
DE, BD, HL, HL/TL, and BD/TL between males 
and females of the mudsleeper B. koilomatodon. 
The results revealed that some of the factors 
depended on the gender. For example, BD, HL, 
and DE/HL had significant differences between 
females and males at the 5.0% level (one-way 
ANOVA, P< 0.05). The reason for these 
differences was that the body size of males was 
more massive than females. There were no 
statistical differences in the other parameters 
(ANOVA, P> 0.05). 
Note: DHTV: Duyen Hai, Tra Vinh; CLDST: Cu Lao Dung, Soc Trang; TDST: Tran De, Soc Trang; HBBL: Hoa Binh, Bac Lieu; 
DHBL: Dong Hai, Bac Lieu and DDCM: Dam Doi, Ca Mau; number in parentheses: number of fish collected at each site; the vertical 
bar is the standard error of the mean; different letters (a, b, c, and d) represent the significant differences. 
Figure 4. The variation in body weight at the six sampling sites 
a
c,d
d
a,b
c
b,c
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
DHTV (90)CLDST (110) TDST (66) HBBL (351) DHBL (216)DDCM (230)
F
is
h
 b
o
d
y
 w
ei
g
h
t 
(W
, 
0
.0
1
 g
)
Sampling sites
Morphometric and meristic variability in Butis koilomatodon in estuarine and coastal areas of the Mekong Delta 
812 Vietnam Journal of Agricultural Sciences 
Note: DHTV: Duyen Hai, Tra Vinh; CLDST: Cu Lao Dung, Soc Trang; TDST: Tran De, Soc Trang; HBBL: Hoa Binh, Bac Lieu; 
DHBL: Dong Hai, Bac Lieu, and DDCM: Dam Doi, Ca Mau; number in parentheses: number of fish collected at each site; the 
vertical bar is the standard error of the mean; different letters (a and b) represent the significant differences. 
Figure 5. The variation in fish total length at the six sampling sites 
Note: Number in each column: number of fish collected in each season; the vertical bar is the standard error of the mean; different 
letters (a and b) represent the significant differences. 
Figure 6. The influence of season × gender on the variation of fish body weight 
Note: DHTV: Duyen Hai, Tra Vinh; CLDST: Cu Lao Dung, Soc Trang; TDST: Tran De, Soc Trang; HBBL: Hoa Binh, Bac Lieu; 
DHBL: Dong Hai, Bac Lieu, and DDCM: Dam Doi, Ca Mau; the number in each column: number of fish collected at each site; the 
vertical bar is the standard error of the mean; different letters (a, b, and c) represent the significant differences. 
Figure 7. The influence of season × site on the variation of fish body weight 
a
b b
a
b b
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
DHTV (90) CLDST
(110)
TDST (66) HBBL (351) DHBL (216) DDCM
(230)
F
is
h
 t
o
ta
l 
le
n
g
th
 (
T
L
, 
0
.1
cm
)
Sampling sites
148
147313 455
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Dry WetF
is
h
 b
o
d
y
 w
ei
g
h
t 
(W
, 
g
)
Seasons
Female Male
24 47 18 172 103 9766 63 48 179 113 133
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
DHTV CLDST TDST HBBL DHBL DDCM
F
is
h
 b
o
d
y
 w
ei
g
h
t 
(W
, 
g
)
Sampling sites
Dry Wet
a 
a 
b 
b 
Lam Thi Huyen Tran & Dinh Minh Quang (2020) 
https://vjas.vnua.edu.vn/ 813 
Note: Number in each column: number of fish collected in each season; the vertical bar is the standard error of the mean; different 
letters (a and b) represent the significant differences. 
Figure 8. The influence of season × gender on the variation of fish total length 
Note: DHTV: Duyen Hai, Tra Vinh; CLDST: Cu Lao Dung, Soc Trang; TDST: Tran De, Soc Trang; HBBL: Hoa Binh, Bac Lieu; 
DHBL: Dong Hai, Bac Lieu, and DDCM: Dam Doi, Ca Mau; the number in each column: number of fish collected at each site; the 
vertical bar is the standard error of the mean; different letters (a, b and c) represent the significant differences. 
Figure 9. The influence of season × site on the variation of fish body weight 
Table 4 reveals the differences of the 
meristic parameters between the dry and wet 
seasons. The season factor had more of an effect 
than gender on all the criteria except BD, BD/TL, 
and HL/TL (one-way ANOVA, P> 0.05). The 
HL/TL ratio of B. koilomatodon was independent 
of all three interactions consisting of gender × 
season, gender × site, and season × site (two-way 
ANOVA, FGenxSea = 0.536, FGenxSite = 0.556, 
FSeaxSite = 0.700, P> 0.05). A similar result was 
also found for the BD/TL meristic parameter. 
The other parameters did not change by the 
interactions of gender × season, gender × site, 
and season × site at a significance level of 5% 
(FGenxSea = 4.311, FGenxSite = 3.161, FSeaxSite = 
14.134, P> 0.05). Particularly, the DE/HL ratio 
was only affected by season × site (FSeaxSite = 
13.815, P< 0.05). Last but not least, ED/HL was 
impacted by season x site plus the gender x site 
interaction (FGenxSite = 3.719, FSeaxSite = 8.941, P< 
0.05). The results suggested that sexes, seasons, 
habitats, and the interaction between them did 
not have a clear affect on the meristic criteria of 
Butis koilomatodon. Similar results 
148 147313 455
5.6
5.8
6.0
6.2
6.4
6.6
6.8
7.0
7.2
7.4
7.6
7.8
Dry Wet
F
is
h
 t
o
ta
l 
le
n
g
th
 (
T
L
, 
cm
)
Seasons
Female Male
24 47 18 172 103 9766 63 48 179 113 133
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
DHTV CLDST TDST HBBL DHBL DDCM
F
is
h
 t
o
ta
l 
le
n
g
th
 (
T
L
, 
cm
)
Sampling sites
Dry Wet
a a a 
b b b 
c c c c c c 
b 
a 
b 
a 
Morphometric and meristic variability in Butis koilomatodon in estuarine and coastal areas of the Mekong Delta 
814 Vietnam Journal of Agricultural Sciences 
were found in Periophthalmodon septemradiatus 
(Dinh et al., 2018) and in Glossogobius 
Sparsipapillus (Nguyen et al., 2020), two goby 
species that co-habitat with B. koilomatodon in 
the Mekong delta. 
Conclusions 
In this research, the specimens of Butis 
koilomatodon expressed differences in 
morphometric and meristic criteria according to 
 Table 3. The variation in meristic parameters of B. koilomatodon between genders 
Morphometric parameter Gender Number of fish Mean Standard deviation t P 
ED 
Female 295 0.34 0.05 
5.16 0.53 
Male 768 0.36 0.05 
DE 
Female 295 0.31 0.08 
3.73 0.73 
Male 768 0.33 0.08 
BD Female 295 1.28 0.23 7.62 0.01 
 Male 768 1.41 0.27 
HL 
Female 295 1.68 0.22 
11.76 0.005 
Male 768 1.86 0.26 
HL/TL 
Female 295 31.89 2.59 
1.24 0.33 
Male 768 31.89 2.42 
BD/TL 
Female 295 24.19 2.72 
0.02 0.85 
Male 768 23.97 2.63 
ED/HL 
Female 295 27.35 5.41 
2.95 0.08 
Male 768 26.31 5.07 
DE/HL 
Female 295 24.11 6.24 
1.55 0.001 
Male 768 23.47 5.49 
 Table 4. The variation in meristic parameters of B. koilomatodon between seasons 
Morphometric parameter Season Number of fish Mean 
Standard 
deviation 
t P 
ED 
Dry 461 0.35 0.06 
0.66 0.00 
Wet 602 0.36 0.05 
DE 
Dry 461 0.34 0.09 
6.01 0.00 
Wet 602 0.31 0.07 
BD 
Dry 461 1.43 0.27 
6.00 0.08 
Wet 602 1.33 0.25 
HL 
Dry 461 1.84 0.29 
2.74 0.00 
Wet 602 1.79 0.24 
HL/TL 
Dry 461 31.44 2.43 
5.25 0.22 
Wet 602 32.23 2.44 
BD/TL 
Dry 461 24.35 2.75 
3.44 0.81 
Wet 602 23.79 2.56 
ED/HL 
Dry 461 25.39 4.73 
6.85 0.01 
Wet 602 27.52 5.33 
DE/HL 
Dry 461 23.95 6.09 
1.48 0.00 
Wet 602 23.41 5.41 
Lam Thi Huyen Tran & Dinh Minh Quang (2020) 
https://vjas.vnua.edu.vn/ 815 
genders, sites, and seasons as well as the 
interactions between them. The data indicated 
that this species reached the highest values of 
body size in the dry season. In addition, the 
highest values of its body size were recorded in 
DHTV. These results would provide useful 
information for further studies about the 
influence of food availability and geographical 
environment on the morphological 
characteristics of this mud sleeper. 
Acknowledgements 
We are grateful to the Ministry of Education and 
Training for funding support (Project No.: 
B2019-TCT-02), and Nguyen Thi Nha Y, 
Nguyen Huu Duc Ton, Nguyen Thi Thuy Hien, 
Tran Chi Canh, and Dang Hoa Thao for assisting 
in fish collection and data analysis. 
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