Journal of Threatened Taxa | www.threatenedtaxa.org | 26 July
2018 | 10(8): 12103–12107
The ecology and
distribution of percoid fish Dario neela from Wayanad
in the Western Ghats of Kerala, India
Dencin Rons Thampy 1 & C.P. Shaji 2
1,2 Centre For Wildlife Studies, Kerala
Veterinary and Animal Sciences University, Pookode, Wayanad, Kerala 673576, India
1 Permanent address: Kolanjiyil
Tharavad, Seethamount Post,
Pulpally, Wayanad, Kerala
673579, India
1 densinrons@gmail.com, 2 shajibarb@gmail.com
(corresponding author)
doi: http://doi.org/10.11609/jott.3393.10.8.12103-12107
| ZooBank:
urn:lsid:zoobank.org:pub:AD8921DE-BB6B-4B26-872B-DB3071AA6FE1
Editor: Neelesh Dahanukar,
IISER, Pune, India. Date of publication: 26 July
2018 (online & print)
Manuscript details: Ms
# 3393 | Received 03 March 2017 | Final received 01 July 2018 | Finally
accepted 11 July 2018
Citation: Thampy, D.R. & C.P. Shaji
(2018). The ecology and
distribution of percoid fish Dario neela from Wayanad in the
Western Ghats of Kerala, India. Journal of Threatened Taxa 10(8): 12103–12107; http://doi.org/10.11609/jott.3393.10.8.12103-12107
Copyright: © Thampy & Shaji 2018. Creative Commons
Attribution 4.0 International License. JoTT
allows unrestricted use of this article in any medium, reproduction and
distribution by providing adequate credit to the authors and the source of
publication.
Funding: None.
Competing interests: The authors declare no competing interests.
Acknowledgements: The study was a part of the dissertation work, done for the fulfillment of M.S Wildlife Studies program at KVASU-
CWS. The authors are grateful to the
course director, Centre for Wildlife Studies, KVASU and all the teaching
faculties of CWS for all the moral support.
The authors sincerely thank the Department of Forest and Wildlife,
Government of Kerala for providing the permissions and for their kind support
throughout the study. Authors are
extremely thankful towards Dr. M. Ashokkumar,
Dr. Rajeev Raghavan and Mr. M. Bipin Paul for their
cooperation and support during the study period.
Abstract: Dario neela, a newly described badid
fish endemic to the Western Ghats is little known to science. Distribution and
ecology of this species is not well documented.
In this paper, we provide information on new records of this rare fish
from Wayanad region of the Western Ghats and discuss
its distribution, ecology and conservation.
Keywords: Badid fish, conservation, distribution,
ecology, endemic, new records.
The genus Dario
Kullander & Britz,
2002, of the family Badidae are known by three
species from the Western Ghats, viz, Dario urops Britz, Ali &
Philip, 2012, D. huli Britz
& Ali, 2015, and Dario neela Britz, Anoop & Dahanukar, 2018. Dario
neela is at present known only from the type
locality, an unnamed stream joining Periya Stream a
tributary of Kabini River in Wayanad,
Kerala, 11.824160N & 75.862500E, 738m (Britz et. al 2018).
At present,
the further distribution of Dario neela is not
known, although the presence of Dario species in Wayanad
is known from the collections by Francis Day about 140 years ago (Britz et al. 2012).
The perusal of ichthyological literature until
Britz et al. (2012) avows that none of them reported
the presence of Badis or Dario from the
Western Ghats of Kerala and Wayanad in particular (Shaji & Easa 1995, 1997; Easa & Basha 1995). None of them could locate the specimens from
Day’s locality, which may either be due to the rarity of the species or
unavailability of the exact location of Day’s collection. Dario neela
was described in 2018 based on the collections from Wayanad
and the study also suggested that Day’s collections were in fact Dario neela and not Dario urops
(Britz et al. 2018).
A
recent survey in the Kabini watershed of the Cauvery
basin in Wayanad helped in documenting the further
distribution of this species in the Kerala part of the Western Ghats (Fig.
1). We provide new information on the
habitat and ecology of the species. Specimens were collected and a few were reared
in captivity to study the social and reproductive behavior of the species.
Materials and Methods
Fishes were collected mostly by sieving with
clothes and mosquito nets. A few specimens were fixed in 10% formalin
and transferred into 70% ethanol for permanent storage. Ten individuals with two males and eight
females were selected, grouped and reared under
captivity to study the social and breeding behavior of the species.
Physical
parameters of the stream habitat, viz, substrate,
canopy cover, stream temperature, stream type, and stream width were recorded
at each collection site. Substrate was
classified as bedrock, boulder, cobble, pebble, gravel, sand, and mud. Canopy cover was measured using a spherical densiometer.
Temperature was measured using a submersible digital thermometer (Mextex- Multi Thermometer).
Elevation, altitude and latitude of sampling locations were recorded
using global positioning system meter (Garmin- GPS 72H) (±10m). Morphometric measurements were taken
point-to-point to the nearest 0.1mm using digital calipers.
Results
The
morphological data of the species is given in Table 1.
There
is an appreciable difference in the morphological attributes of male and female
(Images 1 & 2). Males were larger
than females with well-developed fin rays.
The pectoral fin length and caudal fin length were found to be higher in
males when compared with females. Caudal
peduncle length and pre-anal length were higher in females.
Distribution
in Wayanad
The specimens
were collected from seven different localities of South Wayanad
Forest Division, viz., Kuttyamvayal-Myladi
Stream and an unnamed stream of Banasura forests, Valaanchola Stream of Lady Smith’s RF, Chekuthankundu
Stream of Lakkidi RF (Image 4), two unnamed streams
of Kurichyarmala and Chembra
and from two locations in North Wayanad Forest
Division, from the Periya Stream (Image 5) and the
type locality, a small unnamed stream joining Periya
Stream (Table 2). All these are lower
order streams draining into Kabini, an east flowing
river (Fig. 1). All these collection
localities were sections of the streams flowing through evergreen forest
patches and the species could be recorded from an elevation range between
700–1,050 m.
Habitat and Ecology
The flow rate
was minimal and the collection localities were characterized
mostly by pools and runs. The
substrates were constituted by sand, mud, gravel, pebbles, boulders and bed rocks. Boulders
and sand dominated in the study cites altogether (80%) and the average
constitution of the pebbles and gravels were of 10% in the sites of
collection. All the collection sites
were characterized by heavy litter fall over various substrates. The water temperature varied from 17.9–22.6 0C. The canopy cover varied from 70.38–97.43
%. The physical parameters of various
sites at the time of collection are given in Table 3. Shallow regions of the streams were heavily
occupied by vegetation like Lagenandra sp.,
Colocasia sp. etc. which acted as fish
cover. D. neela specimens were mostly collected from
submerged leaf litter, tree roots, submerged vegetation and Ochlandra
clumps. The co-occurring species
recorded from various collection localities were Devario
cf. malabaricus, Barilius
gatensis, Haludaria fasciata, Schistura cf. nilgiriensis, Schistura semiarmata and Neolissochilus
wynaadensis.
Although not a
shoaling species, D. neela tend to live in
small groups of 5-–10 individuals in the wild, with a well-defined territory
for each individual. The
groups are typically formed by two males and several females defending
territories near each other. In
such groups, one male always dominated the other invariably. Larger dominant males defended larger
territory when compared with the inferior male and females. The dominant males were darker colored (black
with a bluish tinge) and the colour disappeared when
the animal was stressed (Image 3). The
distal margin of the fins were an iridescent blue-green. The inferior males were greyish brown in colour with faded brown vertical bands which fade away soon
after preservation. The distal margin of fins were similar in colour
and appearance to that of dominant males.
Females were smaller than males and had a beige-brown colour on the body with irregular vertical bands and the
fins were devoid of the iridescent colour. The caudal
spot was present in all specimens (Image 1).
Breeding behavior
The spawning
behavior of Dario neela was studied in a
well-planted glass tank, which mimicked the natural ecosystem from where the
fish were collected. A large tank (190L)
was used to study the social and breeding behavior of the species. Tank water properties like pH and temperature
were almost similar to the stream condition.
The tank was planted with locally available aquatic vegetation like Lagenandra toxicaria
and Cabomba sp. Hiding spaces were provided in the form of
large rocks and artificial caves. The
substrate was set with sand and leaf litter collected from the streams.
Dominant males
mostly occupied the heavily planted regions of the tank with enough hiding
spaces and aggressively defended the territory (typically 40cm2)
from the inferior male and females.
Females were found to hide under leaf litter and rocks, while the
inferior male defended smaller territory when compared to the dominant male.
Male Dario neela chased the females and displayed his bright
colors to attract the females, shivering and shaking his body. Gravid females when ready to spawn followed
the male to his territory. Mating is usually attained by a spawning embrace, where the
mates wrap around each other (Fig. 2).
The female released eggs after two to three fake matings
and the males fertilized it. Eggs were
usually scattered in dense vegetation, in caves or under leaf litter. After spawning, the male chased away the
female preventing her from eating the eggs.
Eggs were found to hatch within 48 hours in normal conditions, with the
larvae hiding in vegetation immediately after hatching. Males were found to protect their territories
aggressively after spawning.
Table 1. Morphometric data of the Dario neela
(n=11) collected from different
locations in Wayanad.
|
Morphometric data (mm) |
Range |
Mean |
SD |
|
Total length: |
28.4–38.6 |
33 |
5.1 |
|
Standard length: |
23.1–31.1 |
27.2 |
4 |
|
Head length: |
7.9–9.4 |
8.6 |
0.7 |
|
Eye Diameter: |
2.4–2.6 |
2.5 |
0.1 |
|
Depth of body at D.O: |
7.2–9.6 |
8.5 |
1.2 |
|
Depth of body at A.O: |
6.4–8.9 |
7.8 |
1.3 |
|
Inter Orbital Width: |
2.3–3.9 |
3.1 |
0.8 |
|
Snout Length: |
0.6–1.9 |
1.2 |
0.6 |
|
Dorsal fin Height: |
4.1–6.4 |
5.5 |
1.2 |
|
Pectoral fin Length: |
4.2–6.8 |
5.2 |
1.3 |
|
Ventral fin length: |
3.3–6.2 |
4.8 |
1.4 |
|
Anal fin Length: |
3.4–6.9 |
5.4 |
1.8 |
|
Caudal peduncle length: |
3.4–4.2 |
3.8 |
0.4 |
|
Caudal fin length : |
5.3–7.5 |
5.8 |
1.5 |
|
Pre-dorsal length : |
7.7–11.3 |
9.9 |
1.9 |
|
Pre-Anal length: |
14.6–18.5 |
16.6 |
1.9 |
|
Pre-–Pectoral length : |
8.1–9.6 |
8.8 |
0.7 |
|
Pre- pelvic length: |
8.6–10.5 |
9.6 |
0.9 |
|
Length of the base of dorsal fin: |
12.5–16.1 |
14.4 |
1.8 |
|
Length of the base of Anal fin: |
4.7–6.9 |
5.8 |
1.1 |
|
Inter nostril distance: |
1.3–1.7 |
1.5 |
0.2 |
|
Height of Caudal peduncle: |
2.3–4.2 |
3.5 |
1 |
|
Morphometric data (%SL) |
Range |
Mean |
SD |
|
Head length |
30.2– 34.1 |
32.0 |
2.8 |
|
Eye diameter |
8.3–10.3 |
9.4 |
1.4 |
|
Depth of body at dorsal origin |
30.8– 32.4 |
31.5 |
1.1 |
|
Depth of body at anal origin |
27.7–30.2 |
28.8 |
1.8 |
|
Inter orbital width |
9.9– 12.5 |
11.2 |
1.8 |
|
Snout length |
2.5 –6.1 |
4.2 |
2.4 |
|
Dorsal fin height |
17.7–22.2 |
20.1 |
3.1 |
|
Pectoral fin Length |
17.5–21.8 |
19.1 |
3.0 |
|
Ventral fin length |
14.2–19.9 |
17.3 |
3.9 |
|
Anal fin Length |
14.7–22.1 |
19.6 |
5.2 |
|
Caudal peduncle length |
13.5–14.7 |
14.1 |
0.8 |
|
Caudal fin length |
16.7–24.1 |
21.2 |
5.1 |
|
Pre-dorsal length |
33.3–39.4 |
36.3 |
4.2 |
|
Pre-Anal length |
59.4–63.2 |
61.3 |
2.6 |
|
Pre-Pectoral length |
30.8–35.0 |
32.8 |
2.9 |
|
Pre-pelvic length |
33.7–37.2 |
35.4 |
2.4 |
|
Length of the base of dorsal fin |
51.7–54.1 |
53.2 |
1.6 |
|
Length of the base of anal fin |
20.3–22.1 |
21.2 |
1.3 |
|
Inter nostril distance |
5.4– 5.8 |
5.6 |
0.2 |
|
Height of caudal peduncle |
9.9–15.3 |
12.9 |
3.7 |
Table 2. Physical settings of the habitat of Dario neela
|
Location |
GPS location |
Elevation (m) |
Stream type |
Stream width (m) |
Substrate |
Water temperature (C) |
Canopy Cover (%) |
|
Myladi-Banasura |
11.663300N & 75.931820E |
864.4 |
Pool |
3 |
Sand (50%) Mud (50%) |
19.00 |
89.45 |
|
Banasura- Unnamed Stream |
11.638860N & 75.925240E |
779 |
Run |
3.3 |
Sand (40%) Mud (20%) Boulders (40%) |
18.70 |
97.43 |
|
Valaanchola- Lady Smith’s RF |
11.626250N & 75.962170E |
848.9 |
Run |
4 |
Sand (30%) Gravel (10%) Pebbles (10%) Bed Rock (50%) |
17.90 |
96.51 |
|
Chekuthankundu- Lakkidi RF |
11.518080N & 76.043320E |
857 |
Pool |
7 |
Sand (70%) Boulders (20%) Gravel (10%) |
18.60 |
95.98 |
|
Kurichyarmala- Unnamed Stream |
11.595570N & 75.981480E |
1019 |
Pool |
2.5 |
Boulder (80%) mud (20%) |
18.90 |
93.22 |
|
Chembra-Unnamed Stream |
11.550430N & 76.098740E |
1046 |
Run |
2.2 |
Sand (80%) Mud (20%) |
21.50 |
75.12 |
|
Periya Stream |
11.824650N & 75.846040E |
741 |
Run |
8.5 |
Sand (50%) Mud (20%) Boulders (30%) |
22.60 |
70.38 |
|
Type locality at a small unnamed stream
flowing into Periya Stream |
11.82410N & 75.862500E |
738 |
Run |
1.5 |
Sand (50%) Mud (10%) Boulders (40%) |
21.43 |
76.52 |
Discussion
Dario
neela
is the only species of badid fish known from the
Western Ghats of Kerala. The present
study described the distribution of this rare species in the Wayanad part of Nilgiri Biosphere
Reserve. Dario urops
was described based on the specimens collected from a stream draining into Barapole tributary of Valapattanam
River in Karnataka and the specimens collected by Francis Day (1875–1878) from Wayanad were originally assigned to this species (Britz et al. 2012).
A recent study (Britz et al. 2018), however,
revealed that the specimens collected from Wayanad is
in fact a separate species and named it as Dario neela,
referring to its blue coloration.
Dario
neela
could not be recorded from any other locations outside Wayanad
and in Wayanad the species could be recorded only
from the east flowing streams draining into the Kabini
River, suggesting that the species is endemic to the Kabini
River System in the Western Ghats of Kerala.
The
population trends of this species is not well studied and the present study
indicates that the species is a habitat specialist, recorded only from less
disturbed clear water mountain streams which might have accounted for its
rarity.
The antiparallel spawning embrace has been
reported in Badidae, Anabantoides,
Nandidae and Channidae by
Barlow et al. (1968). A similar type of spawning embrace was
observed in Dario neela. The present success in captive breeding helps
in developing future ex situ conservation plans for this species.
References
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(1968). Badidae,
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Britz, R. & A. Ali (2015). Dario huli,
A new species of Badid from
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Britz, R., A. Ali & S. Philip (2012). Dario urops,
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