Citron Barb (Pethia lutea), a new barb species discovered from Western Ghat Rivers of Maharashtra (Image Courtesy: Ralf Britz/JOTT)
Researchers studying the fish diversity
in Western Ghats Rivers have discovered a yet unknown species of fresh water barb
from the Western Ghats River systems in the Indian state of Maharashtra. The new
species belongs to the Pethia genus of fishes which constitutes barbs found
only in South Asia and Myanmar region.
A view of Bharathapuzha (Image Credit: Wiki Media Commons/ Jjvellara)
Implement urgent conservation efforts or the
rich and endemic fish wealth in the largest river in the Western Ghats of
Kerala will remain only on papers, warns a new assessment on the threats to the
fish diversity in the Bharathapuzha River, locally known as River Nila.
Through a survey on all the four major
tributaries of the Bharathapuzha River system - Gayathripuzha, Chitturpuzha,
Kalpathipuzha and Thoothapuzha – the study recorded 117 species of fishes in
Nila with the highest species richness from the stretch between Parali to
Purathur estuary. Among this, 33 are found only in Western Ghats and three are
found only in Bharathapuzha River system.
A group of researchers including A
Bijukumar, Department of Aquatic Biology and Fisheries, University of Kerala,
Siby Philip from Department of Zoology, Nirmalagiri College, Koothuparamba,
Anvar Ali and Rajeev Raghavan from Conservation Research Group, St Albert’s
College, Kochi and S Sushama from Department of Zoology, NSS College Ottapalam
carried out the study which is published in the Journal of Threatened Taxa.
Top Ten Threats to River Nila
Despite the richness, the river system of River Nila is under threat from human interference, says the study which is published
in the Journal of Threatened Taxa. “Several anthropogenic stressors including
deforestation and loss of riparian cover, dams and other impoundments,
pollution, sand mining, non-native species, climate change and destructive
fishing practices are threatening the fish diversity of Bharathapuzha River
system”, it says.
Threat
#1: Sand mining
Most notorious, most widely known but most
rampant, despite being regulated (encouraged ?) by the il-legal machinery. If
we number the threat based on the calamity it brings, this one goes to top. The
study marks the region between Pattambi and Thiunavaya as the superhot stretch
of legal and illegal sand mining. Studies conducted by CESS in 1997 itself has
shown that the rate of sand mining is way too above the rate of sand generation
in Nila.For many fishes in Nila, Sand is the
breeding substrate, and is the single crucial link that supports the aquatic
food web. With the indiscriminate sand mining, it is just a matter of time for
fishes like Glossogobius giuris and Sicyopterus griseus to vanish from Nila
forever, warns the study.
Threat
#2: Dams and impoundments
Known fact: Big dams are a major threat to
the rich and endemic fish diversity of Nila, since they change the turbulence
of the river causing high sedimentation and other problems. Lesser Known fact:
Dozens of smaller check damk dams across Nila are also doing the
same. Bigger dams are fixed in number so far – Nila has 11 irrigation dams.
Impoundments are still proliferating, turning out to be a lesser noticed diversity
killer in Nila. It has severely affected the movement of certain fish species
and is believed to be a reason for the near absence of eels in the river
system.
Threat
#3: Pesticide pollution
When it comes to a River system like Nila,
don’t think it is just the factories that are pushing chemicals to the water. River
basin dependent extensive agriculture and plantations are also contributing
their fair share to polluting this blood line of middle Kerala. Chemical
fertilizers, pesticides, chemical nutrients, weedicides, you name it. The
resulting eutrophication- the facilitation of aquatic plant growth which in
turn decreases the available oxygen in the water, killing the aquatic fauna- is
a major issue, especially from Chamravattom to Purakkad, says the study.
Threat
#4: Urban sewage
Read Pattambi. According to the study, the
town of Pattambi which falls under the Palakkad District of the state of Kerala
is a major source of urban sewage which pollutes the river extensively, taking
over the pollutant cocktail made by the agro-pollutants.“The urban sewage canals directly open into the
river, through which the municipal waste is dumped. Such large scale pollution
not only degrades the habitat but also causes endocrine disruptions and several
other physiological imbalances in fish including breeding failure which could
ultimately lead to their extirpation”, says the study.
Threat
#5: Deforestation
According to the study, deforestation in
its catchment areas like Mangalam, Nelliyampathy, Walayar, Malampuzha,
Nellipuzha, Dhoni and Kalladikode is a major threat. The loss of natural native
vegetation has triggered the invasion by exotic plants. Not only that the
fishes loose a food resource, the high sedimentation rate due to deforestation
is changing the natural composition of the river bed. It makes survival
difficult for many endemic loaches in the river since they use the pebbles in the
river bed for breeding.
Threat
#6: Lime stone mining
Lime stone mining is rampant in certain
areas of the catchment of the river, says the study. This is especially
prominent in Malampuzha, part of the Kalpathipuzha tributary. The study claims
that the lime stone mining in the catchment areas is leading to pollution and
siltation in the stream. Apart from triggering an unnatural rise in the
silicate content in the water, the dumping of mining debris also damages
smaller streams in the system like Seemanthinipuzha.
Threat
#7: Alien species
The study has spotted at least six
non-native fish species in Nila. While three of them were non-native to Indian
rivers, three were from the Gangetic plains. Though the Indian major carps were
introduced as part of aquaculture, considered as a success, the study was able
to spot them from lower reaches of the river, revealing that they have
proliferated though the river beyond their actual reservoirs. Such
proliferation of non-native species often wipes out native species in the fight
for resources. Species foreign to India like the Nile Tilapia and Mozambique Tilapia
were also spotted from Nila, showing that the alien invasion is possibly stifling
the endemic fish fauna of the river. However, the surprise factor was that the
study reportedly failed to fetch another notorious alien species – African catfish- which is a known diversity killer in Western Ghats Rivers.
Threat
#8: Climate change
Studies conducted in 2010 and 2011 discovered
that the temperature in the Bharathapuzha basin has been on the rise for a 36
year period from 1969 to 2005. Moreover, rainfall data shows that the Nila
watershed gets less rainfall than the state average. Though the temperature
rise is often cited as an impact of climate change phenomenon and the
increasing anthropogenic pressure in the river banks of the Nila, its effect on
the biodiversity of the river system is scarcely studied.
Threat
#9: Aquarium fish trade
Comes in many colours –state supported as well
as clandestine. This greed trade is especially wiping away endemic and
beautiful fishes like Miss Kerala (Sahyadri
denisoni) and Mesonoemacheilus
remadevii, the latter being found only in river system in Silent Valley
which is part of the Bharathapuzha River System. As per a recent study, Miss
Kerala has been found to be collected in massive amounts from Thoothappuzha
tributary for pet trade.
Threat
#10: Destructive fishing practices
Last, but not the least, as always. Poisoning,
use of mesh nets and dynamiting – small effort, good catch. Though traditional
fishermen abstain from practices like dynamiting, it is raising a major threat
to the fish diversity in the tributaries where the traditional fishermen are
lesser in number, warns the study.
Action
Time: Conservation Points to save Nila
Prioritizing integrated watershed programmes.
No more new medium or big dams, cautious about new check dam
proposals.
Channelize district River Management Fund to Eco restoration
of stretches of Nila.
Regulation of sand mining has been proved to be futile. So
finding an eco-friendly alternative to sand is the only option left. But that will be like legalizing marijuana- you have to
first convince the cartels before you convince the government. (They will have
to take it, since the sand is running out and the weed is on the rise).
Beg people not to use pesticides or agro-chemicals near the
river bed cultivations (otherwise also).
Regulate large scale riverbed cultivation.
Establishing Aquatic Biodiversity Management Zones (ABMZ) to
conserve river stretches known to shelter endemic and rare fishes.
Regulate the greedpet trade
and destructive fishing practices, not to say dynamiting.
Above all, let people know – ask them, request them, beg
them, threaten them – You may go the extreme since water is the life blood of
the green earth, as River Nila is for Kerala.
Periyar Tiger
Reserve (PTR) is not just a safe haven for the tigers, but for some aliens too,
in the ecological sense. African cat fish (Clarias gariepinus), one of
the most dangerous invasive alien species, is lurking in the Periyar Lake,
raising serious threat to the rare fishes found only in Periyar, say
researchers. To bring a twist to the story, PTR is going to have the first of
its kind action against exotic fish species in Western Ghats as a group of researchers
and activists are aiming to manually remove African cat fish from Periyar with
public participation.
According to Conservation
Research Group- a research and activist platform based in St Albert’s College
in Cochin- which organises the exotic fish removal campaign at Periyar Tiger
Reserve, the endemic fishes found in the Periyar Lake are severely threatened
by the biological invaders like African Cat fish, which inspired them to
organise such a crusade against the alien fish species of PTR. “Eight endemic fishes in Periyar Lake are
fighting for survival as their only remaining habitats are threatened by
several stressors of which biological invasion is the most significant one.”,
says an official statement from the group.
Importance of Fish fauna in Periyar Lake
An on-going Rufford
Foundation supported project to study the impact of alien species in Periyar
Lake points out that the fish fauna in the Lake are very unique and valuable.
“It (The Lake) holds the only remaining population of six globally threatened
endemic fish species viz. Crossocheilus periyarensis, Garra periyarensis, Hypselobarbus periyarensis,
Lepido pygopsistypus, Nemacheilus menoni and N. Periyarensis”, it says. According to an IUCN report on the
Status and distribution of freshwater biodiversity in the western Ghats, Lepido pygopsistypus is the only member of its subfamily of snow
trout fishes to be reported from south of Himalayas.
According to the
researchers, there are four exotic fish species found in Periyar Lake which
comes under the reserve among which African Cat fish is the most dangerous one
when it comes to threat to native species. Cyprinus
carpio, Oreochromis mossambicus and Poecilia
reticulate are the other exotic fish species found in the Periyar Lake
Stream System (PLSS). Recent studies have indicated that the population of these
exotic fish species are showing an increase which means that the threat to
native species is growing. “C. carpio and
O. mossambicus now dominate the fishery of Periyar Lake and are known to
compete with endangered species such as L.
typus and Crossocheilusperiyarensis”, says a recent study report issued by
IUCN.
The invasive
species have swept away many native fish species found in the lake earlier.
During the last 50 years, at least 16 fish species earlier found in the lake
has disappeared, say researchers.
Fighting the Aliens
African Cat fish
in Periyar Lake and other freshwater ecosystem in Western Ghats is the usual story
of an introduced species turning viral threat to native species. African Cat
Fish was once widely used as a farm fish in Kerala and elsewhere for its rapid
growth. It soon became very popular with its ability to survive in a range of
water qualities and to devour anything from slaughter house waste to standard
fish foods. However, the alarm started ringing when some of them have escaped
through the natural water channels from fish farms during monsoon and reached
the fresh water systems in Western Ghats.
Exotic Fish removal campign at Periyar Tiger Reserve
The IUCN report
has suggested that “the biggest future challenge to fish conservation in PLSS
will be the management and control of C. gariepinus, whose opportunistic
strategy and ability to establish large and persistent populations makes it an
imminent threat.”
To fight the
alien menace, a workshop conducted by researchers and forest officials at PTR
in December 2012 has decided to take pro-active action against the invasive species. Field work has revealed
high population of African cat fish in the canal draining into the Lake. The
authorities and researchers are planning to net out the exotic fishes from the
canal and manually remove the exotic fishes from the Lake. The organisers of
the event were not available for immediate comment. However, according to an official
invitation, the programme is scheduled on April 29th and 30th
of this month.
Far-famed for the silence of the cicadas(though now they are aplenty) and the endemic
Lion Tailed Macaque, the Silent Valley National Park in Kerala, India has just
got another endemic organism to its credits, when researchers identified a new species
of stone loach from Kunthippuzha which flows through the
National Park.
Balitora Jalpalli, new stone loach species from Kunthi River in Silent Valley National Park (Image Credit: Josin Tharian)
According to a study published in the Journal of Threatened
Taxa, the new species of Stone loach differs from its close relatives in head length,
caudal peduncle depth, maximum head width and in the number and pattern of bands on the dorsal side. It has a different number of ventral fin
rays and pectoral fin rays than its close relatives also.
Water Lizard of Kunthi
River
The newly identified fish belongs to the genus Balitora, and is named as Balitora Jalpalli. According to the
authors of the study, the fish was named so for its lizard like
characteristics. 'Jal’ means Water and ‘Palli’ means Lizard in the local
language, making ‘Jalpalli’ equivalent to ‘Water-lizard’. It “refers to the
lizard like appearance of the fish, and its habit of clinging to the rocks in
fast flowing streams,” says the study. According to the researchers who have
conducted the study, the newly identified stone loach can be commonly called as
Silent Valley Stone Loach as well.
The researchers were able to spot the fish from
Valleparathodu, near Poochippara from the Kunthi River which is a tributary of
Bharathappuzha, a major river in the state. According to the study, this
habitat is a high altitude stream which is usually inhabited by other fishes
like Mesonoemacheilus remadevii, Homaloptera pillai, Bhavania
australis and Garra menoni.
Genus Balitora
consists of 11 to 12 species of fishes so far among which two were reported
from Kerala. The new species discovery makes the Balitora
strength in state to three.
Conservation
Significance of Western Ghats Rivers
The identification and description of B. Jalpalli from Western Ghats comes on close heels to a similar species discovery from Krishna River, yet another major river in Western Ghats. Researchers
have identified and described another species of Balitora - Balitora Laticuda - from Krishna River in 2012. These
new discoveries point out to the rich but unexplored aquatic fauna of Western Ghats Rivers and the exigency to conserve the freshwater ecosystem in the
region.
However, habitat destruction is rampant in Western Ghats
Rivers due to anthropogenic pressure. According to the study, immediate
conservation efforts and taxonomic explorations should be carried out in the
area to unearth the unraveled marvels of biodiversity here. “The description of
one more species of freshwater fish from the Western Ghats reiterate our views
that the ichthyofauna of the region continues to be poorly known and is in need
of increased exploratory surveys and associated taxonomic research”, say the
researchers.
Rajeev Raghavan and Anvar Ali of Conservation Research Group
(CRG), St. Albert’s College, Kochi,
Josin Tharian of Laboratory for Systematics and
Conservation, Department of Zoology, St. John’s College, Anchal, Shrikant
Jadhav, Zoological Survey of India (ZSI) and Neelesh Dahanukar of Indian
Institute of Science Education and Research (IISER) co-authored the paper in the Journal of Threatened Taxa..
Western Ghats Rivers have a bounty of yet unknown aquatic
fauna. Recently, a new member was added to the Indian aquatic fauna when a
group of researchers found that a fish known to villagers living on the banks
of Krishna River in Satara District of Maharashtra, is unknown to science. After
conducting follow up studies and comparing it with already described similar species
in India, they have established that it is indeed a new species. NeeleshDahanukar, IISER Fellow at the Indian Institute of Science Education and
Research, Pune who was part of the research team, talks about the finding of the
new stone Loach from Krishna River with Indian Biodiversity Talks.
Balitora laticauda, teh new stone loach found from Krishna River in Northern Western Ghats
Image Courtesy: Sunil Bhoite
It is indeed
interesting to know that the Western Ghats Rivers still keep organisms new to science.
Will you please tell us how your team happened to find the fish?
Sunil Bhoite, who is a naturalist working in Satara
District, Maharashtra, first caught this species in 2009 and sent it to Dr.
Shrikant Jadhav, a scientist in Zoological Survey of India, WesternRegionalCenter, Pune.
habitat near Krishna River bridge
from where Balitora laticauda was found.
Image Courtesy: Sunil Bhoite
During our
collaborative work on the freshwater fish diversity of the northern Western Ghats, Dr. Jadhav showed me this species as an
interesting specimen of genus Balitora.
In 2011, Dr. Jadhav and I had an opportunity to visit the ZSI headquarters in
Kolkata during which we studied the comparative material of related species. We
realized that the species of Balitora
from Satara is indeed a new species, still unknown to science.
In collaboration with Sunil Bhoite, who collected more
specimens of the species early this year, Dr. Shrikant Jadhav and I worked on
the species description and the findings are now published in Journal of Threatened Taxa. We also
received some additional specimens of this fish from another locality in the same
river from Madhavi Chavan and comparative material of Balitora mysorensis from Rahul Kumar, which were very important in
the study.
Though the fish is
new science, it had a local name. Were the locals using the fish for any
cultural or other purpose?
This fish does not have any cultural value nor does it have
any food value. However, sometimes tribal people (called Katkari) catch these
and similar hill stream loaches and sell them in the local fish market. The
species, however, is rare and is only seldom seen in the market.
With your finding, it
is clear that the Western Ghats Rivers still have aquatic fauna which is yet to
be described. Considering the rapid pace at which Western
Ghats water bodies are polluted, do you think many of these
unknown species will stop to exist even before we find them?
In the recent IUCN report on the threats to freshwater
diversity of the Western Ghats (http://data.iucn.org/dbtw-wpd/edocs/RL-540-001.pdf)
it was suggested that about 60% of the total endemic freshwater fish species of
the Western Ghats are threatened because of several anthropogenic stressors
including organic and inorganic
pollution of the water, biological
resource use (food fish and aquarium trade), invasive species, residential and
commercial developments and natural system modification.
Typical habitat of Balitora laticauda
Image Courtesy: Sunil Bhoite
Especially in the northern Western Ghats such rapid
developments are highly uncontrolled and they are modifying the natural ecosystems
posing severe threats to the aquatic biota. On one hand, while the habits of
the freshwater fishes, especially the specialists like hill stream loaches that
require fast flowing clear water with a good substratum, are getting lost or
severely affected; on the other hand we are still discovering species new to
science.
Unless we take efforts for conservation of the habitats and keep a
check on the various anthropogenic stressors, it is quite likely that several
freshwater fish species will go extinct even before we know them and describe
them scientifically.
Is there any specific
threat to the newly described species?
There are no specific threats in the vicinity of type
localities of the newly described species. However, potential threats to the
habitat include severe sand mining upstream of type locality and agricultural
run–off entering into the river. Some organic and inorganic pollution in the
area is contributed by the washing of cloths and vehicles. Some river stretches
in the vicinity of the habitat also have human settlements which contribute to
household wastes directly being added to the river water.
Confirming the rich biodiversity potential of the Western
Ghats biodiversity hot spot, researchers have identified and described a new
Stone Loach from Krishna River in Northern Western Ghats. The new fish which is
named as Balitora laticauda or Palmas
Stone Loach, was spotted from three
different parts of Krishna River in Satara district of the Indian state of
Maharashtra.
Balitora laticauda or Palmas Stone Loach Image Courtesy: Neelesh Dahanukar
The finding which
is published in the latest issue of the Journal of Threatened Taxa, claims that
the new fish is different from all known species of stone loaches, in its appearance and characteristics.
It has at least 7 most distinct characteristics
from its closest relative B. mysorensis described from the Cauvery River
in neighboring state of Karnataka in 1941. It has 10 traverse bands on the dorsal
side while the caudal peduncle is deeper than that of the known, closely
related species, says the research paper.
The new finding
adds a 19th member to the Balitora genus which includes stone
loaches found in the hill streams of south and south East Asia. The researchers
have spotted the fish from the stream of Krishna River drainage at Venegaon
Village, Urmodi River near Nagthane Village and from Khodashi village.
"I got one specimen (of the fish) through my student. By perusal of literature, I was surprised that the present species is quite unlike to its allied species. Meanwhile I came in contact with Sunil Bhoite, a naturalist from Satara and told him about the collection of more specimen from his locality. After one year, he caught some specimen from Urmodi river. After detailed study, I was sure it is new to science.", said Dr. Shrikant Jadhav, Zoological Survey of India, Pune, who described the fish.
New to science, but known to locals
Though the species is new to science, it was not so for the
local people in the villages on the banks of the river. Locals call the fish ‘Palmas’
in Marathi which interestingly points to the appearance as well as behavioral characteristics
of the fish. In local Marathi, ‘Pal’ means Lizard and ‘mas’ means fish,
probably pointing to its lizard like appearance and its habit of clinging to
the rocks in the river.
Habitat of Balitora laticauda Image Courtesy: Sunil Bhoite
According to Neelesh Dahanukar, IISER Fellow at the Indian
Institute of Science Education and Research, Pune, who was part of the research
team, Katkari tribes used to catch this fish along with other stone loaches to
sell in the local market. “The species, however, is rare and is only seldom
seen in the market”, he said.
As per the research paper, the researchers have named the
fish laticauda for its deeper caudal peduncle
which makes it different from its close relatives found in India. Latus in Latin means ‘broad’ and cauda means tail.
Conservation significance
Despite getting attention from the scientific community, the
life of Palmas stone loach may not be so easy in the face of rapid depletion
of natural habitats in Western Ghats. Highly uncontrolled rapid developments
are modifying the natural ecosystems, especially in the northern Western Ghats,
posing severe threats to the aquatic biota, says Dahanukar. “Unless we take
efforts for conservation of the habitats and keep a check on the various
anthropogenic stressors, it is quite likely that several freshwater fish
species will go extinct even before we know them and describe them
scientifically. “, he says.
Pointing out that the fish lives in clear and swift waters
of the streams with rocky bottom, the research paper also notes that the indiscriminate
sand mining in the vicinity of the Krishna River can be a potential threat to
the species.
Moreover, there is an urgent need to conserve the depleting habitat of the river since the research team hints that there could be more aquatic organisms here which are yet to be scientifically described. "There is also scope to discover some species from the region on which we are working.", said Dr. Shrikant Jadhav.
African
Mushi, that is what the farmers in Kerala called that beefy fish, which
guaranteed profit for meager investment and care. It ate anything from wastes from
slaughter houses and was able to live in any type of water qualities. Moreover,
the fish grew faster and bulkier. Within months, a harvest will fetch you kilograms
of fish meat from an average fish pond.
Clarias gariepinus
But the
after effects were horrid. Recent research reports indicate that the fish has
started appearing in fish catches from rivers and lakes in Kerala. Multiple
reports suggest that this fish is now commonly caught by fishermen in the lower
reaches of Periyar River in Kerala, which is known to house fresh water fresh
species only found in Western Ghats Rivers. Similar reports also indicate that the fish is
present in the commercial catches from the Periyar Lake also.
The
writing on the wall is clear. The fish has escaped from fish farms which were
connected to natural water bodies and have proliferated in the Western Ghats
Rivers and other water bodies in the area. The species is known to devour and
sweep away native fish species and other aquatic organisms locally.
The
issue is not restricted to rivers in Kerala. It is reported that this invasive
fish has also reached the Indrayani River in the southern Deccan Plateau
eco-region. It presently raises serious threat to the only
existing population of rare Sisorid catfish Glyptothorax poonaensis
found in India. Sisorid catfish is listed as endangered by IUCN.
According
to IUCN, the southernmost region of the Western Ghats Rivers house more endemic and lesser known fishes in the region. Unfortunately, the devouring African Cat
fish has infected the same parts.
Abundance of Globally Threatened fish species
in Western Ghats Rivers. It can be seen that they are
more found in the Southern region.
Experts
have also expressed concern over the impact of the presence of this African
catfishes on lesser known subterranean fishes in Western Ghats. Ichthyologists
were able to record just six to seven species from these enigmatic fishes which
live in a subsurface ecosystem found under the laterite foot hills of Western
Ghats. The chances of the African Cat fish eliminating many of these enigmatic
creatures even before the researchers are able to spot and record them are not
rare.
There is
an urgent need to restrict the aquarium trade and unregulated fish farming.
Educating buyers and farmers as well as formulating a proper policy for the
management of invasive species are exigencies in this regard.
Western Ghats is the catchment area of 3 large
rivers, 13 medium and 17 minor rivers which play a crucial role in the rich
biodiversity of the region and the prosperity of some 105 million people living
in the area. However, these blood lines of the region are under threat mainly
from the burgeoning anthropogenic factors in the name of development and flawed
policies.
Abundance of Globally Threatened fish species in the Western Ghats Rivers
According to an in-depth study report
submitted to the Western Ghats Ecology Expert Panel about major threats to the
riverine ecosystem in the region, dams, mining, tourism, pollution, flawed
agriculture practices and deforestation of the riparian cover (forest patches
along the river banks) are causing visible degradation to the riverine
ecosystems in this World Heritage site. However, K. A. Subramanian who made the
study also includes the presence of alien species in the riverine ecosystems in
the region as another threat.
Alien species, despite their name, do not
come from another planet, but are introduced from non-native ecosystems often
for agricultural purposes, as ornamental organisms or even as biological
controllers. IUCN has identified introduction of invasive as one of the
possible reason for the population decline of native organisms.
Invasive Plant Species in Western Ghats Rivers
Many of the aquatic invasive species in
streams and water bodies in the Western Ghats like Salvinia molesta, Pistia
stratiotes, Eichhornia crassipes, Hydrilla and Ipomea
fistulosa were first introduced as
ornamental plants in aquariums. They later found their ways to the water
bodies, now spreading to almost all rivers in the Western Ghats.
The changes
in the flow pattern and excessive pollution have also helped in the spread of
these weeds, especially in catchments which are reeling under the pressure of
populated areas. By spreading over the water, they clog the flow of the stream
and increase the rate of sedimentation. They cover the water surface, often
without allowing the sunlight to pass through, eventually wiping away the
submerged species of plants by blocking their chances of photosynthesis.
Mikania
macarantha – a Green Threat to the Riparian Biodiversity
Mikania macarantha, is a similar weed which raises
serious threat to other plant species in the streams and riparian ecosystem of
the rivers in the Western Ghats. This plant forms a thick layer over the stream
and the associated riparian forest blocking the sunlight.
Mikania macarantha, an invasive plant in WG rivers
It is
often observed that the invasion of the Mikania macarantha is closely
connected to the presence of degraded riparian forest patches in the course of
the stream. For instance, in many places like Agasthyarmalai and Anamali
region, the weed has been observed as first colonizing streams using degraded
shores in estates and forestry plantations, gradually invading into the healthy
riparian cover in the adjacent forest areas in the upstream gradually degrading
them over a period f time.
Exotic fishes: friend- turned foes?
Exotic
fishes are another destructive species which is raising serious threat to
native organisms in the Western Ghats Rivers. Introduced for aquarium trade, fish farming and as biological controllers, they have invaded the rivers
spreading all over the river network in the area.
Gambusia affinis was widely used as a biological
agent to check the growth of mosquitos. However, their introduction to water
bodies in the region paved their way to reaching Western Ghats wide river
ecosystems. The species have now reportedly colonized many hill streams,
especially in parts of Maharashtra. Though they don’t eat up each and every
native species like some other invasive species do, they raise fierce
competition for resources with native species, often wiping them away locally.
Clarias gariepinus
Clarias gariepinus, the notorious African catfish pet
named African Mushi among fish farmers in Kerala and neighboring states, has
made a bad example of bringing in foreign species for increased production.
According
to an IUCN report on threats on fish diversity in Western Ghats Rivers, Cyprinus
carpio, Oncorhyncus mykiss, Pangasianodon hypophthalmus, Oreochromis
niloticus, O. mossambicus, Osphronemus goramy, Pterygoplichthys
multiradiatus, Piaractus brachypomus, Trichopodus trichopterus, Xiphophorus
maculatus, Poecilia reticulata and Gambusia affinis are listed as
major invasive threats.
Among
these, C. carpio, O. mykiss, G. affinis and O. mossambicus
are listed among the top hundred worst invasice alien species database.
According to IUCN, these dangerous species are more present in the Southernregion of the Western Ghats where the endemism is highest compared to other
areas.
Absence of a national policy for managing
invasive species
According
to the report submitted to the Convention on Protection of Wetlands, Government
of India admits that presence of invasive species has been raising serious
threat to the conserved areas in the country. The document also admits that
there is no management policy or guidelines issued in this direction. But the
government should take immediate actions to make a management policy to check
more invasive species reaching to the pristine ecosystems and degrading them
gradually.
If you think the wonder world of unknown fishes exists only
in the dark trenches of the deep sea, you may be wrong. There are umpteen
fishes and other aquatic creatures which live below the surface of the earth in
groundwater tables often moving through the small cervices of the stones under earth’s
surface.
Like their counter parts in the deep sea, these shy fishes
rarely come out to light, so our knowledge is very much restricted about this
hidden aquatic biodiversity. A recent study sheds some light into these lesser
known subterranean fishes in India.
Horaglanis and Kryptoglanis -
the Enigmatic fish genus of Western Ghats
Horaglanis Krishnai, The Indian blind catfish
The members of the Horaglanis genus appear to have a
prominent mouth at the anterior terminus of the head and transparent skins
which reveals the blood vessels. One of the most noticeable feature is the
pectoral fin changing into a vestigial bud and the terminal positioning of the
anterior nostrils.
Interestingly, the fishes which were observed in laboratory
conditions were found to be able to raise their heads up and down with the help
of hinges at the Pharyngeal region( photo (a)). This is no mean feat since such an ability is
absent in known fish species.
Two species of Horaglanis
have been reported from India- H.
Krishnai and H alikunhi, both
from Kerala. H. Krishnai is distinct with its 23 fin-rays in the dorsal fin and
the 16 fin-rays in the anal fin. Another species which is considered as H.
inquirenda or species which is yet to identified, is also known and was reported from Kerala recently. This organism
has the 20 fin-rays on its dorsal fin and the 15 fin-rays in the anal fin as
their distinguishing marks visibly.
Kryptoglanis – a new genus to the world of subsurface fishes
A new study has added Kryptoglanis,
an unreported genus among catfishes to the acquatic fauna of India recently.
Known as Middu in regional Malayalam, the first identified member of the genus
is K. Shajii, spotted in Kerala.
Kryptoglanis Shajii
Members of Kryptoglanis
genus can be identified with the absence of dorsal fin and the presence of
barbels including the barbell pair on their nose. They have smaller subcutaneous
eyes. Other facial features include superior mouth and a projecting lower jaw.
They are reported to have fan like pectoral fins and a long based anal fin
which is confluent with caudal fin. The caudal fin of the fishes in these
species has less than eight fin-rays.
The second species identified from this genus is yet to be
christened officially.
Common features of
aquatic creatures in subsurface ecosystems
All of these fishes have certain common characters including
the absence of eyes and body pigmentation and can be found only in wells that
are connected with underground water channels.
They lack of hard structures like spines or fin is a unique
characteristic of these fishes that helps their movements through narrow rock
cuts. Moreover, they show photophobia or fear for light - and like to stay in
darker places. Since their skin is transparent, cat fishes of Horaglanis and
Kryptoglanis genus have red colour. However the former changes their colour
within hours of continuous exposure to bright sunlight.
Monopterus digressus
An earthworm like fish found from the similar ecosystem
which belongs to Monopterus digressus is a typical
example for the adapted physical characteristics for living inside congested
stone cracks. No eyes, no fin elements, but just a membranous caudal fin tip.
Body of Monopterus digressus is sub-cylindrical with no scales.
Experts suggest that such catfishes occur more in springs
along the segmented valleys and wetlands in laterite foot hills distributed
along the western periphery of Western Ghats. Based on their field experience,
experts point out that artificial wells located on laterite hill slopes close
to a wetland are places where there is a high chance of finding these enigmatic
creatures. The lateritic geography under the earth surface here helps these
creatures to move through narrow cavities in laterite stones.
Possible sub-surface
ecosystem in Western Ghats?
New reports have spotted Horaglanis
species even from 90 km away from the place where it was first spotted,
indicating the presence of the fish along a larger area. Similarly, the new
study also brings in the second report of M
digressus, this time 115 km away from the first locality.
Though it is high time to jump into conclusions, the
indications are enough reasons to believe that a sub surface ecosystem exist in
the Western Ghats which spreads through a larger area and is almost impossible
to explore due to its subterranean nature.
Now watch a pair of Monopterus digressus in action after the break.
What Makes Kryptoglanis different from other similar fishes?
(Photo Courtesy: Current Science Journal, Video Courtesy: Zoological Survey of India)
