Climate change, dams, over-fishing take toll on Himalayan Mahseer

The Himalayan or the Golden Mahseer is a popular game fish that attracts anglers from all over the world to India’s north-eastern states of Assam and Arunachal Pradesh every year.

The sport the Mahseer offers was aptly put into words by H S Thomas in his book Rod in India, where he says, ‘pound for pound the Mahseer is a fish superior in sporting qualities even to the lordly salmons’.

A Mahseer on the fishing rod is the dream of every sports fisherman. The crystal clear waters of the swift and rapid streams and rivers in the north-eastern states host the endangered species of this Cyprinid fish in variant colors – gold, silver, chocolate and burnished copper. A voracious eater, the Mahseer consumes smaller fishes, frogs, crabs to plant matters and attracted by baits – artificial or natural.

Sushen Pao, who served as an administrative officer in Arunachal Pradesh – India’s Northeast Frontier – from 1954 to 1963 wrote in his memoir:

“My angling spree in Arunachal started in Along area. The river Siyom flowing by the side of Along town, the headquarters of present West Siang district, was our resort during holidays where we fished from morning till evening. Whether we caught many fishes or not, we invariably rushed to the bank of Siyom, carrying our packed lunch and fishing gears. I remember one particular incident when one of my friends hooked one big fish and eventually he was pulled by the fish from under the water. My friend struggled to land the fish and went downstream along the river bed for about two kilometers. Some of us ran along with him to assist him in case of any emergency. The fight between the angler and the fish took almost three hours. He was a hefty man with a beer belly and became exhausted and was almost giving up, but we cheered him up and at last he was able to drag his victim towards a shallow point of the river bed and we helped him in the final landing. To our utter disappointment the fish was a Gond fish and not a Mahseer’ (Bokapithia or Jongapithia in Assamese) which we eagerly waited for! There were many good fishing spots upstream of Siyom River in the confluences of streams falling into the Siyom. There are only a few varieties of fish which are lured by a sparkling fishing spoon. They are mainly the Mahseer – the famous fighting fish for whom the sporting anglers hanker for.”

“I caught hundreds of them, especially the Mahseer, weighing about two to five kilograms on the average and feasted with families and friends. Those remained as some memorable moments.”

Considered one of the most valuable game fish in the world and far superior to the trout, the Golden Mahseer used to thrive in large numbers in the rivers on the Himalayan foothills till a few decades ago. Today this-golden hued, large-scaled fish, which can weigh more than 50 kg, suffers both in size and population because of the destruction of its habitat.

In persuit of the Mahseer

St J Macdonald in his book Circumventing The Mahseer, wrote -“In those lands the waters beloved of the noble Mahseer are fringed by giant bamboos waving their graceful fronds over the placid depths, or by splendid trees whose immense serpentine roots are washed by roaring rapids. There will be the dense retreats of the wild elephant, the secure cover for bison and other game, the last barrier put up by long-suffering nature against the s hand of man.”

Mahseer is a widely distributed species in South East Asia. The Golden Mahseer (Tor putitora) is a speciality of this region. In Assam, the snow fed Jia Bhoroli, a tributary of the Brahmaputra that originates in Arunachal and the Manas River are the last bastions of this game fish. The Golden Mahseer and the Chocolate Mahseer are also found in the hilly streams and certain river systems across the Himalayan region. Other species offering sport to anglers here are the Copper Mahseer (Tor mosal), the Chocolate Mahseer (Neolissochilus hexagonolepis), the Chitrahu (Burbus chillionides), the Goonch (Bagarius bagarius), the Mulley (Wallogonia attu), and the Murral (Ophlcephalus straitus) locally called Sal.

The Siang/Brahmaputra river system has around 46 smaller tributaries or sub river systems and the hilly terrain of these systems have within them almost inaccessible gorges holding freshwater fish diversity. The Siang is joined by many tributaries above Pasighat in Arunachal offer excellent angling sites and promises a true sport for the angler. So does the Subansiri – a major tributary of the Brahmaputra that provides a home for the game fish.

Dams have halted its migration upstream for spawning, resulting in sharply reduced numbers. It also faces a threat from fisherman exploding dynamite in rivers to kill and catch them. Ichthyologists worry that if the Golden Mahseer is not allowed to migrate upstream and spawn, it will disappear from the Indian waters.

Listed as endangered in the IUCN Red Data List Status, the fish could be found in abundance till the 1970s in the Manas and the Karnamakura rivers.

The World Heritage Site – Manas National Park – also a tiger reserve, shares international boundary with Bhutan and is also contiguous with the Royal Manas National Park (RMNP).

The transboundary Manas Conservation Area (TraMCA) is a region of biological diversity with intact habitats for Tiger and Asian Elephants. The Mathanguri Forest Rest House in the Indian side and the once Royal Hunting Lodge on the Bhutanese side had photographs and description of various sub species of the Mahseer from the Manas River. The fish has showed a declining trend in the Manas river due to large-scale fishing over the years.

In 2012s, the Royal Manas National Park (RMNP) authorities started preliminary study of fresh water ecology in RMNP to document list of fish species present and found an incredible diversity of freshwater fishes that included the Golden Mahseer and the Copper Mahseer.

Diversity of fish fauna in the north-eastern region

Northeast India, one of the hot spots of fresh water fish biodiversity in the world, (Kottelat and Whitten, 1996) shares its fish fauna predominantly with that of the Indo-Gangetic fauna and to a small extent with the Burmese and South China fish fauna (Yadav and Chandra 1994).

There has been a wide variation in the number of fishes reported from this region ranging from 172 (Ghose & Lipton, 1982) to 267 (Sen, 2000). Four species under Critically Endangered category from this region are Garra litanensis Viswanath, G.manipurensis, Aborichthys garoensis Hora and Lepidocephalus goalparensis (Pillai and Yazdani); of these, three species are endemic to this region. Of the endangered category, seven are found to be endemic.

The National Bureau of Fish Genetics Resources (NBFGR, ICAR), Lucknow and Zoo Outreach Organization of IUCN catagorized as endangered seven endemic fishes of the region -Tor putitora, T tor, Ompok bimaculatus, O pabda, Aborichthys elongates, A tikaderi and Noemacheilus multifasciatus.

Over the years, this rich fish fauna has been tremendously degraded.

In Assam so far, 185 species belonging to 98 genera have been recorded (Bhattacharjya et al, 2000). The fauna has 33 representatives endemic to the region. There can be many more fish species which are yet to be recorded owing to remoteness of the region. Based on the random field surveys conducted during 1996-98 and available literature, 25 fishes have been identified as threatened species facing dangers at various levels.

The tentative check-list includes four endangered species – Tor tor; Labeo dyocheilus; Bengala elanga; Ompok pabda, eight Vulnerable  -T putitora, Labeo pungusia, puntius sarana sarana, Mystus vittatus, M tengara, Pangasius pangasius, clupisoma garua, Anguilla bengalensis, four Rare, Chagunius chagunio, Cyprinion semiplotum, Channa barca, Lepidocephalus goalparensis etc (Bhattacharjya et al,2000).

Several fish species have disappeared over the years or their production decreased considerably due to habitat loss or habitat alteration as a result of siltation, encroachment, organic load interferences, weed infestation and other anthropogenic activities added by indiscriminate fishing of brood fish and juveniles, use of explosive and poisons in fishing or alteration in river flow velocities.

A variety of factors such as construction of dams, deforestation, expanding agricultural practices, discharge of effluents, rampant use of pesticides, removal of gravel and sand from river beds led to the vulnerable status of some species.

Threat to Mahseer

With a 50 per cent decline of this fish species in the past due to over-fishing, anthropogenic effects, loss of habitat and breeding grounds – Mahseer is now considered one of the most vulnerable game fish in this part of the world.

Many Mahseer habitats have become totally barren due to commercial fishing. Besides fishing, development activities have halted its migration upstream for spawning, resulting in sharply reduced numbers.

The foremost threat to fishes in the region comes from construction of mega projects. Dams pose colossal threat to aquatic biodiversity, mainly due to alteration of water flow regime and blocking of spawning route for migratory fish species.

The fate of the Golden Mahseer – fast declining in the Subansiri due to indiscriminate fishing – now hangs in balance with a series of hydroelectric power projects.

A report titled ‘Cumulative Impact and Carrying Capacity Study of Subansiri Basin, Including Downstream Impact in Brahmaputra River Valley’ prepared by the Central Water Commission and released by the Ministry of Environment and Forest said that migratory fish like Mahseer and Snow Trouts are likely to be hit due to obstruction to be created by the proposed dams. Scientists predict a further 80 per cent decline if the present trends continue and the proposed dams would only jeopardize the situation.

Climate change results in changes in ecosystem balance that has taken a toll on fish stocks

Apart from man-made factors, climate change has resulted in changes in ecosystem balance that has taken a severe toll on fish stocks. Noemacheilus corica, Noemacheilus savona, Macrobrachium rosenbergii, Cirrhinus reba are other species declining gradually. Many other endemic fish varieties are fast disappearing from our water bodies.  With increase in temperature, evaporation also increases that leads to depletion of surface water level resulting in depletion of aquatic life and vegetation cover.

During a media workshop on ‘Adaptation to Climate Change in the Indian Himalayas’, organized by CEE and The Third Pole in Jorhat, researchers from Assam raised the alarm of a drastic decline in cold water fishes like Mahseers, Snow Trouts and Minor Carps.

While there has been an increasing dominance of small-sized fishes in catches, the Bengala elanga (eleng) and Pangasius pangasius are now almost extinct in the region, revealed experts. Researchers from the State Fishery Department also found key changes in biological functions of fish stocks as an impact of climate change.

Conservation

Dr A G K Menon, of the Zoological Survey of India who investigated the decline of fish fauna in the country under a project ‘Conservation of Freshwater Fishes of India’ spanned from 1991-93, warned that 59 species of freshwater fishes were potentially endangered, vulnerable or rare.

Of the 59 species, 25 came under the endangered category that included the Indian trout (Raiamas bola), the Copper Mahseer, the Deccan Mahseer, Golden Mahseer and so on. His studies found out that apart from habitat destruction, the introduction of alien species have spelt doom to indigenous fish.

Introduction of the common English carp has led to a steady decline in the four species of snow trout. Introduction of the common carp has made the indigenous fish, Osteobrahma belgangeri extinct in the Loktak Lake in Manipur.

Noted environmentalist Dr Anwaruddin Chowdhury said that the disturbing trends revealed by recent studies on the Mahseer – the main indicator of other species in the geological world – reflect a grim scenario and added that ‘there is an urgent need to create awareness among the people regarding conservation of the Mahseer.  The conservation efforts for the fish species are found to be meager. In Assam, the forest department regulates angling and accords permission to anglers on a select stretch and strictly monitors catch and release. While on one hand commercial fishing brought doom to the fish species, angling helped or rather anglers contributed in locating and documenting the species thereby helping in conservation.

The Assam Bhorelli Angling and Conservation Association (ABACA), the oldest angling group in the state has also come up with a hatchery in the Eco Camp Nameri, for breeding and conservation of the Mahseer.

The Jia Bhoreli flows through the Nameri Tiger Reserve in Sonitpur district in the Assam-Arunachal border. The ABACA has appealed to the government and public to put in place strict measures to ensure safe migration of the fish. The need of the hour is to bring into focus and create awareness on fish protection by restricting all types of fishing during the swapping seasons.