Range
extension of Conta pectinata Ng, 2005
(Teleostei: Sisoridae) in upper Brahmaputra River drainage in Arunachal
Pradesh, India
Lakpa Tamang 1& Shivaji Chaudhry 2
1,2 G.B. Pant Institute of Himalayan
Environment and Development, North East Unit, Vivek Vihar, Itanagar, Arunachal
Pradesh 791113, India
Email: 1 lakpatamang@rediffmail.com, 2 shivaji.chaudhry@gmail.com (corresponding author)
Date
of publication (online): 26 February 2012
Date
of publication (print): 26 February 2012
ISSN
0974-7907 (online) | 0974-7893 (print)
Editor: W. Vishwanath
Manuscript
details:
Ms # o2933
Received 01
September 2011
Final received 02
January 2012
Finally accepted 13
January 2012
Citation: Tamang, L. & S. Chaudhry (2012).
Range extension of Conta
pectinata Ng, 2005 (Teleostei: Sisoridae) in upper Brahmaputra River
drainage in Arunachal Pradesh, India. Journal of Threatened Taxa 4(2): 2402–2405.
Copyright: © Lakpa Tamang & Shivaji Chaudhry 2012. Creative Commons Attribution 3.0 Unported License. JoTT
allows unrestricted use of this article in any medium for non-profit purposes,
reproduction and distribution by providing adequate credit to the authors and
the source of publication.
Acknowledgements:We extend our gratitude to Dr. L.M.S.
Palni, Director, Kosi-Katarmal, Almora, Uttarakhand and Dr. P.K. Samal,
Scientist-in-charge, North East Unit, Itanagar, Arunachal Pradesh, G.B. Pant
Institute of Himalayan Environment and Development (GBPIHED) for facilities
provided for this piece of research. Also thanks to Dr. Dhrupad Choudhury,
Programme Coordinator (ICIMOD, Kathmandu, Nepal) for inspiration and encouragement.
Abstract: This paper extends the range of distribution of Conta pectinatain Sille River, Brahmaputra drainage, East Siang District of Arunachal Pradesh
and gives some information on its habitat and threats, which are still to be
documented properly. Some brief additional characters are also added here. Our examination revealed that some
morphological variations exists from originally described C. pectinataby having deep body at anus (10.3–11.9 vs. 7.5–9.4% SL); short
dorsal-spine (length 15.7–20.8 vs. 20.9–24.0% SL), less number of
serrae on anterior margin of dorsal-spine along the entire length (15–18
vs. 18–20) etc. The major
threats identified are the frequent use of electrocution and the chemicals in
the river during the winter season .
Keywords: Aquatic vegetation, Conta pectinata,
electrocution, pectoral spine, range extension, Sille River, threats.
For
figures, images -- click here
The catfish genus Conta belongs to the family
Sisoridae and was first erected by Hora (1950), previously considered as
monotypic. Conta is native to India and
little information is known to science, so far merely two species, namely, Conta conta and C. pectinata are known. C. pectinata was described from the
Brahmaputra River drainage at Dibrugarh, Assam (Ng 2005a) and till date has not
been reported from any other part of the Indian region except Meghalaya
(Vishwanath et al. 2007). Ng (2009)
remarked that there is no information available on the species habitat,
ecology, distribution and population trends. This paper reports range extension of C. pectinata in Sille River, upper
Brahmaputra River drainage in East Siang District of Arunachal Pradesh and
gives a brief description of the species and information on habitat and
potential threats.
Materials and Methods
Sampling was carried out
using a cast net with diameter 2.5m and mesh size 7sq.mm during 13–17 October
2010. Specimens were preserved in
10% formalin and identified following Ng (2005a). Measurements were made point to point with digital calipers
(Mitutoyo Corporation, Japan) to the nearest 0.1mm and expressed as a
percentage of standard length (SL), head length (HL) or length of pelvic to
anal-fin origin (PA-L). Vent to
anal-fin origin is abbreviated as (VA-L). Counts and measurements were made on the left side of the
specimens. Measurements follow Ng
& Ng (1995) and Ng & Dodson (1999); measurements for pelvic to anal-fin
origins and vent to anal-fin origins follow Nebeshwar et al. (2009). The number in parentheses after a
specific fin rays count indicates the number of specimens examined. The length of adhesive apparatus was
measured from its anterior margin to posterior margin. Data on Conta pectinata were obtained from the
literature (Ng 2005a). The specimens are deposited in the Zoological Survey of
India (ZSI), Itanagar, Arunachal Pradesh.
Conta pectinata Ng, 2005
(Image 1)
Conta pectinata Ng, 2005: 16(1): 23–28.
Type locality: Brahmaputra River, Dibrugarh, Assam, India.
Holotype: ZRC 49672, 46.4 mm SL. Paratypes: UMMZ 234675, 1, 47.9 mm SL; ZRC
49673, 2, 44.2-49.1 mm SL.
Material examined
Four specimens, 14–17.x.2010,
42.5–46.4 mm SL, Sille River, about 1km upstream from RCC bridge over
Sille River, about 10 km from Ruksin or about 26 km before Pasighat, 27052’626”N
& 95018’300”E; altitude: 127m; weight: 0.79–0.92 gm, coll.
Lakpa Tamang (ZSI/V/APFS/P-523).
Description
Body
slender, sub-cylindrical anterior, abdomen moderately flat. Head small, V-shaped when viewed dorsally,
wider than deep. Post-temporo-supracleithrum process gently turned outwards towards the
tip. The snout length is equal to
the base length of the occipital process and also equals the length of the
supraoccipital spine. The length
of the thoracic adhesive apparatus is almost equidistant between the pectoral
and pelvic fin origins and also from the snout tip to the middle of the
supraoccipital spine (Image 2). The position of the vent nearer the anal-fin origin (35.5–44.9
% PA-L). The body is
deepest at dorsal-fin origin, deeper than wide; body depth at anus 10.3–11.9%
SL, deeper than wide; length of dorsal-spine (15.7–20.8% SL); dorsal to
adipose distance 30.4–32.7% SL and length of nasal barbel 8.1–11.0%
HL.
Dorsal-fin with 5–6 rays,
anterior margin of dorsal-spine consists of 15–18 strong serrae along
entire length, and posterior margin with 9–15 serrae, both the serrations
pointing towards base. Pectoral-fin with 5(1), 6 (3) rays, anterior margin of
pectoral-spine with 26–32 serrae anteriorly-directed and posterior margin
with 13–16 serrae directed towards base. Pelvic-fin with i, five rays and
length 16.7–18.5% SL. Anal-fin with ii, 7(3) ii, 8(1) rays. Caudal-fin
consists of i,5,6,i (2), i,6,5,i (1), i,6,6,i (1)
principal rays.
Ecological notes
Specimens of Conta pectinata were collected from shallow
(10–30 cm) and moderately clear water with pebbles, cobbles of
variable colours and sand particles, at an altitude of 127m. Other species associated were: Aborichthys
elongatus, Acanthocobitis botia, Amblyceps mangois, Barilius barna, B. bendelisis, Balitora brucei, Botia rostrata, Chanda nama, Crossocheilus
latius, Garra annandalei, G. gotyla, Neolissochilus hexagonolepis, Pseudolaguvia shawi, Psilorhynchus balitora, Puntius ticto, Schistura savona and Tor tor.
Threats: During the winter season
(October–January), some people employ modern hazardous techniques of
fishing like electrocution, use of bleach and lime powder in diverted streams,
in the lower reaches nearby Sille Village where electricity is available. Further, electrocution is also done
using a mini generator or inverter towards upstream and downstream areas. As per the view of the fishermen, the capture
rate of this fish is less in natural conditions in comparison to other
fishes. The catch rate of fish
within 3–4 hours of fishing using traditional methods is about 15–20
individuals and sometimes even less.
Distribution
Known from Sille River, Sille
Village, East Siang District, Arunachal Pradesh. The Sille River is one of the
tributaries of Siang River, which joins the Brahmaputra River in Assam. The species was originally described
from Brahmaputra River, Dibrugarh, Assam and also reported from Meghalaya (Fig.
1). Although Vishwanath et al. (2007) included Meghalaya
in the distribution but the exact locality was not mentioned. Probable locality is given in the map,
i.e., from Umtrao River that flows adjacent to the Guwahati–Shillong road
(W. Vishwanath pers. comm.).
Discussion
According to Ng (2005a), Conta pectinata differs from C. conta in having
anteriorly-directed (vs. distally-directed) serrations on the anterior margin
of the pectoral spine, and having a longer (24.6–25.6% SL vs. 21.9–23.4)
and more slender (2.6–2.8% SL vs. 3.9–4.4) caudal peduncle. The specimens of Conta collected from Sille River
of Arunachal Pradesh agree well with the description of C. pectinata sensu stricto based on the
following characters: (i) Serrae on the anterior margin of the pectoral spine
directed-anteriorly, (ii) in having long (23.0–25.8% SL) and more narrow
(2.7–3.0% SL) caudal peduncle. However, further examination revealed that
some morphological variations exist on the following: deep body at anus 10.3–11.9
(vs. 7.5–9.4% SL); short dorsal-spine (length 15.7–20.8 vs. 20.9–24.0%
SL); long pelvic-fin (length 16.7–18.5 vs. 14.2–16.4% SL); larger
post adipose distance (distance 30.4–32.7 vs. 21.8–25.0% SL) and a
short nasal barbel (length 8.1–11.0 vs. 17.0–23.8% HL). Further, slight
variations exists in the following: less number of serrae on anterior
margin of dorsal-spine along the entire length (15–18 vs. 18–20); a
post-temporo-supracleithrum process moderately deflected from the base of the
supraoccipital spine vs. more deflected (compare dorsal view in Image 1 here
and Fig. 1 in Ng 2005a). We assume these variations might be due to different
ambient microclimatic conditions, habitat and water quality that is beyond the
scope of this study. The long thoracic
adhesive apparatus in this species appears to be an adaptation to life in fast
flowing waters upstream from the Brahmaputra River similar to other erethistids
and sisorids (Hora 1930; de Pinna 1996). According to Ng (2005b; pers. obs.), the individuals
of Hara jerdoni (Erethistidae) seem to remain at rest frequently supported by fin
spines partially or fully erect amongst submerged vegetation. We also assume that the serrated dorsal
and pectoral spine may help the fish to get entangled in aquatic vegetation, as
some individuals were captured in a similar type of microhabitat.
The fish were generally
found more towards river banks where water pressure is
lower, dwelling under congested gaps of small stones or pebbles and also within
the aquatic vegetation. The fish
also dwell in small drainages with pebbly beds and aquatic grasses and feed on
newly developed algae and minute debris particles on the substratum. The fish make clicking sounds when
taken out from the water body (as per the information given by local
fishermen).
The hazardous techniques
used are more dangerous than traditional methods as the fish remain hidden
under the gaps of the substratum which are severely
affected by electrocution and chemicals. This non-conventional method of fishing, enable the fishermen to collect
a large number of fishes in a short time, but it poses a serious threat to this
fish and to other bottom dwelling aquatic fauna (Chaudhry & Tamang
2007). Traditionally, village
fisher women (Mishing community) also collect this fish with a handmade
circular netted disc (made up of cane and bamboo). This operation is done by removing the small stones and
pebbles near river banks and also by dragging it
through banks of small drainages consisting of aquatic vegetation.
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