The microhabitat breadth of Vamanapuram River fish community was studied in detail. The microhabitat variables selected were relative depth, focal point velocity, water column depth, mean water velocity and substrate. Puntius filamentosus had the highest breadth in three dimensions in both stream and river habitats showing a generalistic mode of resource utilization. Garra mullya, Labeo dero and Glossogobius giuris are specialists in the usage of microhabitat variables in the stream habitat while these are G. mullya, Etroplus maculatus and Aplocheilus lineatus in river habitat. Danio aequipinnatus showed extreme variations along focal point velocity variable in both habitats indicating an. opportunistic behaviour

Arun, L.K.

Kingston, S.D.

Natarajan, P.

Aquatic Commons

J. Indian Fish. Assoc., 33: 59-67, 2006 59 
MICROHABITAT BREADTH OF FISH COMMUNITY ALONG 
THE VAMANAPURAM RIVER, SOUTH KERALA 
*S. David Kingston, L. K. Arun and P. Natarajan 
Department of Aquatic Biology and Fisheries, University of Kerala, 
Thiruvananthapuranz- 695 581, India 
*Veterinary University Training and Research Centre (Fisheries), 
Tamil Nadu Veterinary and Animal Sciences University, Parakkai- 629 601, 
India 
ABSTRACT 
The microhabitat breadth of Vamanapuram River fish community was 
studied in detail. The microhabitat variables selected were relative depth, focal 
point velocity, water column depth, mean water velocity and substrate. Puntius 
filamentosus had the highest breadth in three dimensions in both stream and 
river habitats showing a generalistic mode of resource utilization. Garra 
mullya, Labeo dero and Glossogobius giurb; are specialists in the usage of 
microhabitat variables in the stream habitat while these are G. mullya, 
Etroplus maculatus and Aplocheilus lineatus in river habitat. Danio 
aequipinnatus showed extreme variations along focal point velocity variable in. 
both habitats indicating an. opportunistic behaviour. 
Keywords: Vaman.apuram River, fish community, microhabitat breadth, 
focal point velocity 
INTRODUCTION 
The ecology of the environment 
has a bearing on the fish living in it. The 
fish acquires specialization of varying 
degrees in the environment and the 
nature· of specialization depends upon 
the competition between the fish 
species. From the head to the mouth of a 
river, the habitats and characteristics 
vary and the degree of adaptations the 
fish community acquires depends upon 
the resources available. Moreover, 
microhabitat plays an important role in 
structuring the fish community of the 
rivers. The major microhabitat 
resources on which fish segregate can 
be grouped as depth of water column, 
flow rate or velocity and substrate. The 
present study aimed to analyse the 
utilization of microhabitat variables by 
the fish species in the riverine 
environment. The study will help to 
understand the utilization of various 
niche/microhabitat resources in the 
river. The study will also bring to light 
the generalistic and specialistic modes 
of microhabitat utilization by the fish 
community. 
60 S. David Kingston, L. K. Arun and P. Natarajan 
MATERIAL AND METHODS 
Vamanapuram River is a small 
river which forms the lower course of 
Kallar River originating from the 
Chemmungi Mottai at about 1860 m 
above MSL in Western Ghats (Fig. 1). 
The river has a length of 88 km, with a 
drainage area of 687 km2, which lies 
entirely within Kerala state. The annual 
runoff has been assessed as 889 mm 
(Anon, 1974). The microdistribution of 
fish species was studied along 12 
transects in the river. The abbreviations 
of the different fish species are 
furnished inAppendix- 1. 
~~~~~~"~"~~·~·~~·~·-··~~.~·-····-------r··· 
5 
7'! 
l l 
• u s, 
Fig. 1: Location of study sites in Vamanapuram River 
N 
MICROHABITAT BREADTH OF FISH COMMUNITY ALONG 
THE VAMANAPURAM RIVER, SOUTH KERALA 
61 
APPENDIX-1 
AL Aplocheilus lineatus 
AP Amblypharyngodon microlepis 
BB Barilius bakeri 
DA Dania aequipinnatus 
EM Etroplus maculatus 
GG Glossogobius giuris 
GM Garra mullya 
LD Labeo dero 
MA Mystus armatus 
PA Puntius amphibius 
PF P filamentosus 
PM P melanampyx 
PS P sarana 
PT P ticto 
PV P vittatus 
RD Rasbora daniconius 
XC Xenentodon cancila 
The variables studied were relative 
depth, focal point velocity, water 
column depth, velocity and substrate. 
Observations were made for 7404 
specimens representing 17 species. 
Twelve stations representing stream 
and river habitats available in the river 
were selected for the study. Each station 
was sampled at least five times during 
the study period. Microhabitat 
observations were made visually from 
the shore or taken from their position in 
the nets depending on the habitat. Each 
fish was measured for the following 
microhabitat variables: 
Position in the water column which 
gives the relative depth of the fish, i.e., 
distance from surface in relative scale 
0.00 to 1.00 like surface (0.00), high 
(0.0 1 to 0.25), middle (0.26 to 0. 75), 
low (0.76 to 1.00) and bottom (1.00). 
Focal point velocity is the velocity 
at the position of the fish. Focal point 
velocity was estimated for each and 
every fish individually depending on 
the position in the water column and the 
water column depth. 
Water column depth is the depth of 
water at the point where the fish was 
located. 
Mean water column velocity is the 
velocity at 60% depth if the depth is less 
than 75 em or the average of velocities 
at 20 and 80% of the depth if the water is 
>75 em deep (Bovee and Milhous, 
1978). 
The substrate composition was 
taken from an area of0.0625 m directly 
below the fish and the categories were 
based on Wentworth particle scale 
(Moyle and Senanayake, 1984), i.e., (1) 
detritus, (2) mud, (3) silt, ( 4) sand, (5) 
gravel, (6) cobble, (7) boulder and (8) 
bedrock. 
The microhabitat observations 
along stream habitat were made from a 
limited area of the study section, which 
consistently represented the whole 
profile of the study site. In river habitat, 
observations were made both visually 
as well as from the nets. Visual 
observations were made from the shore 
up to the depth of visibility and beyond 
that, the data were collected from tbe 
nets. In most of the places, the depth of 
the water column exceeded the width of 
62 S. David Kingston, L. K. Arun and P. Natarajan 
the net (1.00 m). In such conditions, 
nets were operated twice, one in the 
water column region and another in the 
bottom region. The absolute depth of 
the water column and po"sition of the 
fish in the nets were taken into 
consideration while calculating the 
microhabitat variables. Monofilament 
gill nets varying in mesh size from 6 to 
25 mm were used to catch the fish. First, 
the nets were spread in the water and 
made in a vertical position as far as 
possible. Whenever the position of the 
net is not vertical, the data were 
excluded for microdistribution. Each 
fish observed directly (visual) or from 
the gill nets had all microhabitat 
variables read either directly or 
indirectly through charts. From the 
microhabitat observations, breadth (B) 
was calculated for relative depth, focal 
point velocity, water column depth, 
water column velocity and substrate for 
each species. The microhabitat breadth 
was calculated using the formula of 
Levins (1968): 
B= 1 /Pij' 
where Pij is the proportion of the 
resource in each category. 
High breadth values show a 
generalistic mode of utilization and low 
values indicate more spe·cialistic nature. 
RESULTS AND DISCUSSION 
Microhabitat breadth explains the 
spectrum or range of a patiicular 
variable associated with the fish. The 
breadth observed for the fish 
community in Vamanapuram River 
showed that fishes used a narrow 
spectrum of relative depth resource 
(Table 1). The maximum breadth 
observed was for PF (3.95). GM was 
very pmiicular in its relative depth 
utilization with a breadth of 1.50 which 
is very narrow. The focal point velocity 
variable showed that n1ost ofthe species 
used a narrow range of this variable. 
The highest breadth observed was for 
PF (2.15). The breadth of mean water 
column velocity was also narrow with 
the highest being 1. 79 (PF). The breadth 
of the substrate variable shows that , 
most of the fishes are specific to a 
particular substrate and deviation from 
this is very rare. The maximum breadth 
observed was forPV (3.94). 
MICROHABITAT BREADTH OF FISH COMMUNITY ALONG 
THEVAMANAPURAM RIVER, SOUTH KERALA 
63 
Table 1: Microhabitat breadth offish species in Vamanapuram River 
Species Relative Focal point Water column Mean water Substrate de~th velocity 
PA 3.02 1.08 
PF 3.95 2.15 
DA 2.75 1.46 
RD 3.60 1.29 
PT 2.98 1.34 
PV 2.95 1.00 
PM 2.96 1.00 
GM 1.50 1.00 
PS 2.42 1.00 
BB 2.84 1.18 
EM 3.09 2.00 
MA 2.33 1.00 
AP 3.00 1.00 
LD 2.14 1.39 
AL 2.04 1.00 
GG 1.79 1.00 
XC 3.07 1.79 
NRS 5 3 
NRS -Number of resource states 
The microhabitat breadth observed 
in stream habitat (Table 2) showed that 
most of the fishes used a narrow range 
of the microhabitat variables. The 
breadth calculated for relative depth 
variable showed that PF was using 
almost all the positions in the water 
column with the highest breadth of3.92. 
Conversely, LD, GG and GM were very 
specific in their position in the water 
column with their breadth being 1.00, 
1.00 and 1.30, respectively. The breadth 
calculated for the focal point velocity 
variable was narrow ranging from 1.00 
to 2.05. The highest breadth value was 
associated with PF. BB had a breadth 
value of 1.96. The breadth of water 
de~th velocity 
2.73 1.24 2.06 
3.17 1.79 2.10 
2.36 1.20 2.37 
1.54 0.88 2.30 
2.22 1.42 2.59 
1.94 1.00 3.94 
2.49 1.00 2.15 
2.07 1.22 1.91 
2.38 1.00 1.33 
2.69 1.00 1.99 
2.07 1.00 2.02 
3.14 1.00 1.91 
1.44 1.00 1.95 
1.68 1.17 1.98 
1.26 1.00 2.04 
1.50 1.00 2.00 
1.91 1.70 1.32 
5 2 8 
column depth dimension showed 
variations among the species and the 
highest breadth was observed in PF as 
4.17. MA had a breadth of 3.14. The 
lowest breadth was observed in GG 
( 1.00). A very narrow breadth was 
observed for the variable mean water 
velocity. XC had the highest breadth of 
1. 79. The breadth calculated for the 
substrate dimension showed that PV 
experienced the highest breadth with 
3. 94. LD and GG had the lowest breadth 
values ofl.OO. 
The river habitat experienced 
variations in the breadth of the different 
microhabitat dimensions (Table 3). The 
64 S. David Kingston, L. K. Arun and P. Natarajan 
Table 2: Microhabitat breadth of fish species along the stream habitat of 
Vamanapuram River 
Species Relative Focal point Water column Mean water Substrate de~th velocity de~th velocity 
PA 3.06 1.02 2.92 1.13 2.00 
PF 3.92 2.05 4.17 1.63 2.08 
DA 2.75 0.13 3.20 1.08 2.43 
RD 3.60 1.03 1.07 1.00 2.30 
PT 2.93 1.49 2.82 1.42 2.70 
PV 2.95 1.00 1.94 1.00 3.94 
PM 2.96 1.00 2.49 1.00 2.19 
GM 1.30 1.00 1.99 1.13 2.56 
PS 2.37 1.00 2.38 1.00 1.33 
BB 2.79 1.96 2.59 1.00 2.04 
EM 2.96 1.79 2.35 1.00 1.96 
MA 2.33 1.00 3.14 1.00 1.91 
AP 3.02 1.00 1.44 1.00 1.95 
LD 1.00 1.00 1.32 1.00 1.00 
AL 2.17 1.00 1.52 1.00 1.52 
GG 1.00 1.00 1.00 1.00 1.00 
XC 3.02 1.00 2.03 1.79 2.27 
NRS 5 3 5 2 8 
X 2.60±0.80 1.15±0.44 2.26±0.62 1.13±0.24 2.07±0.67 
NRS -Number of resource states 
Table 3: Microhabitat breadth of fish species along the river habitat of 
Vamanapuram River 
Species Relative Focal Point Water Column Mean Water Substrate De_eth Velocity De_eth Velocity 
PA 2.48 1.17 2.55 1.63 2.27 
PF 3.93 1.92 3.24 1.92 2.04 
DA 2.11 1.98 1.51 1.47 1.42 
RD 2.00 1.00 2.00 1.00 1.79 
PT 2.58 1.00 1.63 1.00 1.10 
GM 1.63 1.00 2.15 1.60 2.27 
BB 2.67 1.92 2.78 1.60 1.79 
EM 1.79 1.60 1.79 1.00 2.00 
LD 2.88 1.42 2.04 1.20 2.89 
AL 1.00 1.00 1.00 1.00 1.00 
GG 2.00 1.00 2.00 1.00 1.00 
XC 2.00 2.00 1.79 1.60 1.60 
NRS 5 3. 5 3 8 
X 2.26±0.70. 1.42±0.42 2.04±0.57 1.34±0.32 1.76±0.55 
NRS -Number of resource states 
MICROHABITAT BREADTH OF FISH COMMUNITY ALONG 
THE VAMANAPURAM RIVER. SOUTH KERALA 
65 
breadth of relative depth variable was 
varying between 1.00 (AL) and 3.93 
(PF) for the different species. A 
maximum breadth of2.00 was observed 
in XC for the variable focal point 
velocity. DA experienced a breadth of 
1.98 and PF 1.92. Variations in the 
breadth of water column depth were 
marked with PF showing the highest 
breadth values (3.24) and AL the 
minimum (1.00). The breadth of mean 
water velocity variable did not show 
much variations and the maximum 
value was observed for PF (1.92). The 
substrate breadth showed variations 
between 1.00 and 2.89. The maximum 
value was associated with LD. 
Based on the microhabitat breadth 
in stream habitat, PF was utilizing a 
wide spectrum of various microhabitat 
resources available. Among the five 
microhabitat dimensions studied, PF 
had the highest breadth in three 
dimensions. On the basis of relative 
depth, PF was utilizing almost all the 
positions in the water column. LD, GG 
and G M had very narrow range of usage 
of the water column. The dimensions 
like focal point velocity and water 
column depth were also broadly utilized 
by PF. In mean water velocity, PF was in 
the second position (1.63) next to XC 
( 1. 79). In substrate variable, utilization 
was comparatively narrow (2.08). 
Among the 17 species studied in this 
habitat, GG had the narrowest 
utilization of various microhabitat 
dimensions. It was confined to the 
bottom region along the sand substrate. 
Its breadth was 1.00 in all the 
microhabitat variables. Comparatively, 
LD utilized a narrow range of 
microhabitat resources. In the present 
study, the breadth of GM, GG and LD 
was more towards a specialistic mode. 
The distribution of fish along the 
water column depth variable showed 
that the fishes were utilizing the shallow 
region of the river explaining the 
tenitorial behaviour of the fish species. 
This may also be due to riparian 
vegetation and availability of more food 
along the shallow region. 
Vamanapuram River is small (length 88 
km) and its fishery is not imp01iant 
economically. Moreover, during the 
pre-monsoon dry season, some of the 
sampling stations were disconnected 
from the main channel forming pool 
like habitats. 
According to Moyle and 
Senanayake ( 1984), based on relative 
depth variable, species with breadth 
values of less than 2.00 are bottom or 
surface oriented fishes while those with 
greater than 4.40 are fishes that use most 
of the water column. Based on this, in 
the present study, GM, LD and GG are 
specialists in streams while GM, EM 
andAL are those in river habitat. 
The breadth for focal point 
velocity was narrow in streams and the 
most specialistic species is DA which 
had a breadth value of0.13. This species 
was observed in high velocity regions 
and swimming against the cunent most 
of the time. Such low breadth was also 
observed in the Kallar stream pools by 
Arunachalam et al. (1988) and in Kallar 
River by Arun (1992). This species 
66 S. David Kingston, L. K. Arun and P. Natarajan 
showed high breadth values for focal 
point velocity in river habitat (1.98) 
showing a generalistic mode. Such 
extreme variation in between the 
habitats indicates the opportunistic 
behaviour ofthe species. · 
From the mean microhabitat 
breadth values, it could be concluded 
that PF is a generalist in microhabitat 
utilization along stream as well as river 
habitats. The extreme specialistic fish 
species were GG in stremn and AL in 
river. PA showed least variations in 
breadth values between habitats and LD 
had major difference in mean breadth 
values. Comparing the mean values, 
extreme variation was observed for four 
species, viz., PT, LD, ALand GG. These 
species are opportunistic in character 
and they are capable of utilizing the 
available resources without much 
specialisation. Among these four 
species, LD is highly opportunistic and 
flexible in microhabitat utilization. 
Among the five microhabitat 
variables studied in Vamanapuram 
River, high degree of resource 
utilization was observed for relative 
depth variable in stream and river 
habitats. This is clearly evident from the 
high mean values obtained for this 
variable. Thus, separation within the 
relative depth variable was very 
effective in spatial partitioning 
arrangement for the Vamanapuram 
River fish assemblage. 
Studies on the tropical fish 
. communities in rainforest streams of Sri 
Lanka by Moyle and Senanayeke 
(1984) in terms ofmicrohabitatbreadth 
is comparable to the present study. 
However, the resource states selected 
by them were more ( 11) when 
compared to the present study (5). 
In temperate Californian streams, 
Moyle and Vondrecek (1985) observed 
that each group had a relatively narrow 
breadth in at least one dimension 
compared to most of the other species. 
In the Black Creeks of Mississippi 
River (USA), Baker and Ross (1981) 
observed that the cyprinids 11tilize the 
water column dimension more 
effectively than other variables. 
ACKNOWLEDGEMENTS 
The first two authors are thankful 
to Dr. Koos Vijverberg, Limnologisch 
Instituut, The Netherlands, for 
providing a fellowship under the joint 
collaboration of the NIOO and the 
office of the International Co-operation 
ofthe University ofLeiden. 
REFERENCES 
Anon, 1974. Water Sources ofKera1a. 
Public Works Department, 
Government of Kerala, 
Trivandrum. 
Arun, L. K., 1992. Niche Segregation 
in Fish Communities of a South 
Indian River. Ph. D. Thesis, 
University ofKerala, Trivandrum. 
Arunachalam, M., Nair K. C. M., 
Vijverberg, J. and Kortmulder, 
K., 1988. Food and habitat usage 
MICROHABITAT BREADTH OF FISH COMMUNITY ALONG 
THE VAMANAPURAM RIVER, SOUTH KERALA 
67 
of cyprinid fish assemblages in 
stream pools of a South Indian 
river. Internal Report No. 1988-
1990. Limnologisch Institute, 
Nieuwersluis, Netherlands, 89 pp. 
Baker, J. A. and Ross, S. T., 1981. 
Spatial and temporal resource 
utilization by southeastern 
cyprinids. Copeia, 1981: 178-189. 
Bovee, K. D. and Milhous, R. T., 1978. 
Hydraulic stimulation in instream 
flow studies: Theory_ and 
technique. Instream Flow Paper 
No. 5, US Fish and .wildlife 
Services, Office of Biological 
Services. FWS-OBS:78-33. 
Levins, R., 1968. Evolution in 
Changing Environments. 
Princeton University Press, New 
Jersey. 
Moyle, P. B. and Senanayake, F. R., 
1984. Resource partitioning 
among the fishes of rainforest 
streams in Sri Lanka. J Zool., 
202: 195-223. 
Moyle, P. B. and Vondrecek, B., 1985. 
Persistence and structure of the 
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Californian stream. Ecology, 66:1-
13. 


Microhabitat breadth of fish community along the Vamanapuram River, south Kerala

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Microhabitat breadth of fish community along the Vamanapuram River, south Kerala

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