Report on the status of Golden Mahseer in Ramganga River 2010.

BACKGROUND

The following is a report on the findings of a study conducted by Mahseer Conservancy in collaboration with the Wildlife Institute of India on the status of Golden Mahseer populations in the Ramganga River and investigations into possible reasons for their apparent decline. The research was conducted during a 6 week period in March and April 2010.

The golden mahseer occurs across the Himalayas and inhabits the streams and rivers that drain the lower Himalayan terrain. The large surface area of its fins, cylindrical body and muscular tail are adapted to suit the montane water environments in which it lives. These are characterised by steep gradients, a high rate of flow, high oxygen content and cold, clear waters. The golden mahseer is a migratory fish that moves upstream into smaller tributaries and feeder streams in the monsoon for spawning. These streams serve as fresh feeding grounds and appropriate sites for depositing their spawn. The mature adults descend back down to the larger rivers after the rains leaving the fry and juveniles in the more suitable, shallower waters that have a lower flow rate.

It has been widely documented that golden mahseer populations are declining across India but comprehensive studies with data to confirm these trends are largely lacking. The species was categorised as endangered by the National Bureau of Fish Genetic Resources in 1992 but a combination of human impacts are contributing to their continued demise. These include:

1. Altering of habitat and impediment of migration through the construction of dams.
2. Killing of fry, fingerlings and brood fish through the use of indiscriminate fishing methods such as dynamiting, electrocution and poisoning.
3. Destruction of habitat and seasonal spawning grounds caused by siltation resulting from mining, pollution and water extraction.
4. Reduction of habitat caused by water extraction and global warming.

The Golden Mahseer is particularly vulnerable due to the specific environmental conditions needed to feed and spawn successfully and its relatively low fecundity rate. The declining trend in their numbers is therefore cause for great alarm and widespread conservation initiatives are needed immediately to safeguard the future of the species.

Study Area

The study area is a 15km stretch of the Ramganga River up and downstream of Bhikyasain, Almora district, between the points +29° 40′ 9.96″N +79° 13′ 58.62″E and +29° 47′ 6.36″N +79° 14′ 50.10″E. 

Satellite map of study area 

The Ramganga originates from the high altitude zone of the Doodhatoli ranges in the district of Pauri Garhwal, Uttarakand. The river then runs south west through scattered villages and agricultural land for 140km before entering the Corbett National Park. Downstream of the protected area the river meanders another 300km before draining into the Ganges near Farrukhabad, Utter Pradesh.

The Ramganga is the lifeblood of the Corbett National Park and is largest of the precious few perennial sources of water in the protected area. The park was established in 1936 and protects an immense diversity of flora and fauna including, of course, the critically endangered Bengal Tiger. In 1974 the park was chosen as the location to launch Project Tiger and now, due to the thick jungle forest and rich diversity of species supported by the Ramganga, hosts one of the highest Tiger densities in the world.  The river also provides crucial habitat other important and threatened species such as the endangered gharial, mugger crocodiles, otters, turtles, a multitude of bird species as well as the fast declining golden mahseer.

The study area is located approximately 20km north of Corbett National Park but despite the short distance it is in stark contrast to the pristine ecosystem of the protected area.  Destructive human activities such as sand mining, over extraction of water and indiscriminate fishing using dynamite, electrocution and bleaching are degrading the river ecosystem and decimating fish species such as the golden mahseer. The river resources of the area are controlled by the Forest Department but currently no patrols are being carried out to monitor the river and nothing is in place to stop the damage being done.

Furthermore, the golden mahseer is a migratory fish that travels great distances upstream to spawn in smaller streams and tributaries during the monsoon rains. This means that although healthy populations of the species are protected in the Jim Corbett National Park these fish still have to run the gauntlet of traveling through the heavily degraded, highly populated section of river in order to get to and from their seasonal spawning grounds. Therefore, the success of the sanctuaries downstream will be undone unless the intense fishing pressure upstream is successfully managed, especially during the migration periods.

There are a few isolated sanctuaries along this stretch of river alongside temples where fish are protected from all fishing methods. The absolute respect of these areas by the locals means that patrols are not needed and fish populations thrive. These populations attract angling tourism to the area, providing lucrative revenue for the temples. 

Project Aim

‘To assess the threat of damaging human activities to the status of Golden Mahseer populations in the 15km study stretch of Ramganga River, Almora district.’

The aim of the report is to assess the abundance and distribution of golden mahseer populations in the river and identify threats to these populations in order to make informed decisions on how best to protect the species and methods for effective conservation. It is hoped that conservation initiatives started in this area can be used as an example and replicated throughout the subcontinent.

OBJECTIVE 1: Assess the status of Golden Mahseer populations in the study area.

Fish were sampled during a 6 week period in March and April 2010. Sampling was carried out using a traditional cast net with a mesh size of 2cmx2cm. The 15km study area was split into 500m segments, in each segment 2 hours were allotted to make 100 casts.

Fish caught were identified, measured, weighed and photographed before being returned to the water. Morphometric characteristics such as total length, head length, body depth, weight and number of scales along the lateral line were recorded for size class determination and identification confirmation.

Environmental characteristics were also recorded at 100m intervals. When correlated with the fish sampling data this would show which conditions mahseer populations were favouring in the river. The main habitat parameters measured were water speed (fast, medium, slow), water depth (cm), turbidity (high, medium, low), vegetation (yes, no), and substratum (bedrock (> 50 cm), boulders (25-50 cm), pebbles (6-25 cm), coarse and fine gravels (0.2 to 6 cm), and sand/silt (< 0.2)).

The river mainly oscillated between fast flowing, shallow rapids and deep, slow flowing pools. Turbidity of the water was recorded to be clear in every location and vegetation was present in the majority of locations. The substratum of the river bed varied along the river with larger rocks and boulders more common in fast flowing sections and gravel, sand and silt more common in the slow-flowing pools.

5 species of fish were recorded during the sampling period. The percentage of the species of fish sampled was: Golden Mahseer (Tor putitora) – 14%, Rohu (Labeo dero) – 74%, Gotyla (Garra gotyla) – 5%, Barred Baril (barilius barila) – 5%.

                            Chart showing the percentages of species sampled

The results show that rohu greatly outnumbered golden mahseer. Rohu favoured shallow, fast-flowing rapids whereas the golden mahseer were exclusively caught in the deeper pools that were under the protection of temples. The lack of golden mahseer caught suggests that their populations are threatened, however, it could be due to the limitations of the sampling method. The mesh size on the cast net was too large to catch smaller sized fish and where the depth of water was greater than 1m the cast net became ineffective. This meant that shallow rapids were the areas where the cast net was most effective, conditions favoured by the rohu.

In order to overcome these problems an observational approach was also adopted which was possible due to the clarity of the water. Observations were made for 30 minutes at 100m intervals along the study area. We noted that golden mahseer were absent for large stretches of the river. Fish of more than 2kg were exclusively found in the protected areas alongside temples where dynamite is prohibited.  High densities of golden mahseer were seen in these sanctuaries, notably at Senala Temple and Kadar Bridge.

The failure to catch any mahseer outside the protected areas, backed up by observational studies, suggests that fishing pressure is having a huge impact on mahseer populations forcing them to find sanctuary in isolated pools next to temples.

OBJECTIVE 2: Investigate damaging human activities in the study area and their possible impact on Golden Mahseer populations.  

Investigations were carried out by making observations along the river and recording any human disturbance that was occurring. This was backed up by extensive interviews with local people, photographs and video recordings.

Mahseer is a highly valued food fish in this locality and the fishing pressure was found to be acute in order to meet the demand. The main method of catching fish is the use of explosives such as dynamite. More traditional fishing methods such as cast nets, snares and catching fish with hands are also widely used. Electrocution from high powered, overhead cables were mentioned to be used in interviews but this method was not witnessed during the study period.

                      Boys with 7 Rohu and 1 Golden Mahseer caught using dynamite near Bhikyasain

Dynamite is a common and hugely destructive method of fishing used on the river. Explosions were heard 14 times during the study period and witnessed 6 times. During interviews many people said dynamite was being used every day all along the river. The fishing method is not selective; it kills everything within the vicinity of the blast. Fry, fingerlings and other aquatic species are often part of the discarded by-catch. On the 8^th of March a boy fishing downstream of Bhikasain said that a turtle was killed earlier that morning by mistake when a group was fishing using the explosive.  When surveying a deep pool below the village of Naula a woman commented that our efforts were pointless as dynamite was used in the pool every day and there were no longer any fish left.

During the monsoon the larger mature adult mahseer migrate upstream to spawn. These fish are targeted using dynamite, electrocution and nets. When interviewed Birendra Rawat from Bhikiasain claimed that during the monsoon he eats mahseer for lunch and dinner every day. This demonstrates that the success of the sanctuaries downstream will be undone unless the intense fishing pressure upstream is successfully managed, especially during the migration periods. This view was shared by Misty Dhillon, owner of Himalayan Outback near Marchula ‘The protected areas will not be effective unless something is done about the slaughtering of mahseer when they migrate to breed’  

The extraction of sand, gravel and rocks used for building materials is occurring intensively along this stretch of river. Not only is this scarring the river landscape, it also disrupts the natural river ecosystem and will potentially contaminate the local water supply. Clear, fast-flowing and rocky waters are essential for the mahseer to thrive and any changes to these conditions disrupt the fish’s ability to feed and breed successfully. Therefore, siltation of the river caused by mining could potentially have disastrous consequences for the survival of the mahseer. Furthermore, widespread reduction of river levels in the area caused by global warming and over extraction of water exasperates siltation, the effects of which are already being noticed. Chris Summers, an angling guide in the area commented that ‘the water is definitely murkier. In past years it was crystal clear, you could count the pebbles in 6ft of water, now you can’t’.  

15% of the locations observed in the study had some sort of mining activity taking place. In several locations sand was being extracted on a large scale to be sold commercially in the market. Mining was particularly intensive on the Gagas River, a tributary of the Ramganga that runs through Bhikasain. Here, families were mining sand from the river bed every day for jeeps and lorries to collect and transport to the market. This was dramatically altering the natural flow of the river and caused a crater effect with banks of discarded gravel and pools of stagnant water. 40kg of sand was being sold for 20 rupees.  

MAJOR FINDINGS OF OBJECIVES 1 & 2

1. Fishing pressure on the study area is intense.
2. Dynamite is being used extensively on the river, decimating golden mahseer populations.
3. Dynamite produces a large unwanted by-catch including fry, fingerlings and other aquatic wildlife such as turtles.
4. Remaining fish populations are found in small, isolated sections that are protected by temples.
5. The river is not being patrolled to monitor illegal fishing methods.
6. Sand, gravel and rock extraction is occurring intensively along the river to be sold commercially or used personally for construction and repairs.
7. The Gagas River in Bhikyasain is being severely degraded due to sand mining. 40kg bags of sand are being sold commercially for 20 rupees.

PROPOSED ACTION PLAN

• Discuss major findings and issues with village heads and concerned parties.
• Highlight areas suitable for the creation of sanctuaries.
• Hand over beats to villages headed and represented by Van-Panchayats.
• Enforce the ban on dynamite with patrolling guards.
• Start angling-based eco-tourism where licenses are issued by respective villages and guests hosted in family houses

Angling tourism has been successfully implemented as a conservation tool downstream of the study area and it is hoped that this model can be replicated. If the money generated by tourism reaches the local population it provides a clear financial incentive to conserve the fish. It is hoped that by focusing on the golden mahseer as a key species implementing measures to protect and restore its habitat, it will have a positive knock-on effect for the rest of the threatened local wildlife.