Gharial conservation in Nepal:

Chitwan population reinforcement monitoring program

A. Cadi¹, S. Martin², A. Barlow³, L. Fougeirol² et T. Maskey⁴

¹ UMR CNRS Ecologie des Hydrosystèmes fluviaux, Université Claude Bernard Lyon1, 69622 Villeurbanne Cedex, France. Mail : cadi@univ-lyon1.fr

² La Ferme aux Crocodiles, Les Blachettes, 26700 Pierrelatte, France.

Mail : info@lafermeauxcrocodiles.com

³ Tiger Tops Jungle Lodge, Royal Chitwan National Park, Tiger Mountain, Nepal.

⁴ Ministry of Forest and Soil Conservation, Department of National Parks and Wildlife Conservation. G.P.O., box 860, Kathmandu, Nepal.

Abstract

Two species of the family Crocodylidae are found in Nepal : The marsh Mugger, Crocodylus palustris, and the gharial, Gavialis gangeticus. This one has an extremely large slender snout. Adult males have a conspicuous narial excrescence commonly called ghara. It is listed as endangered and on Appendix I of CITES. Gharials are specialised fish-eaters. At present, individuals are distributed in isolated remnant populations in the Karnali, Babai, Narayani and Sapta Kosi river systems. All of them are in, or adjacent to protected areas. The population of gharial in the Sapta Kosi river is low. According to a report compiled by IUCN, crocodile population in the wild have been estimated at 80 to 120 and a confirmed number of 140 in captivity.

Since 1981, the “Gharial Conservation Project” at Kasara in Royal Chitwan National Park has began a program for crocodile conservation. 432 gharials have been released. However, successful captive breeding has not yet been achieved and proper release protocol has to be set up. In order to obtain efficient design management and action for this endangered species, a solid knowledge of their biological and ecological requirements are needed. For those reasons, a new conservation project has been realised in collaboration with La Ferme aux Crocodiles from Pierrelatte (France), the CEPA (Conservation des Espèces et des Populations Animales) and the D.N.P.W.C. (Department of National Parks and Wildlife Conservation) of His Majesty’s government of Nepal. To achieve this objective we have chosen to follow ten new released gharials in the rivers of Royal Chitwan National Park.

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Nepal is more often mentioned for its snowy summits, rather than its subtropical plains called the Teraï. Nevertheless, half of the population of the country lives today on this narrow earth band fertilised since millenniums by waters descending the Himalayas, that runs for more than 800 kilometres between the Nepalo-Indian border and the mountains. Today some parts of this area are protected as the Royal Chitwan National Park (R.C.N.P.). Many protection programs were set up and confided to the King Mahendra Trust for Nature Conservation.

Our team, supported by La Ferme aux crocodiles of Pierrelatte (France) in collaboration with the C.E.P.A. (Conservation des Espèces et des Populations Animales) and the D.N.P.W.C. (Department of National Parks and Wildlife Conservation), tried to discover the reasons of the disappearance of the last gharials (Gavialis gangeticus).

The gharial is the most easily distinguished of the crocodilians because of its long snout. With the saltwater crocodile it is one of the largest living crocodilians (adults up to 6-7m). Adult males grow a bulbous nasal appendage, which resembles an Indian pot called “ghara”, from which the species derives its name. The gharial is typically a resident of deep, fast flowing rivers. It is restricted to the northern part of the Indian continent where they were found in four river systems (Indus, Ganges, Mahanadi and Brahmaputra). Exposed sand banks are used for basking and for nesting (females lay their eggs during the dry season). The gharial appears to be primarily a fish-eating species, but very large individuals are known to eat other prey.

The gharial is one of the most endangered of the crocodilians. However, unlike the other seven most endangered crocodilians, some conservation programs are realised. The species was literally brought back from the brink of extinction by restocking programs initiated first in India in 1975, and in Nepal in 1978. In Nepal, gharials are restricted to remnant populations in the Karnali, Babai and Narayani rivers (tributaries of the Ganges). Total population is estimated between 60 and 100 wild individuals. A captive rearing program has released 432 gharials since 1978 in the different rivers.

During the monsoon (between June and September), the flooding of the rivers and the continuous rains render monitoring impossible. During winter, the level and the temperature of water facilitate the observation of the crocodiles on the sand because of their basking behaviour. In one month (November 2001), we counted only around fifty individuals, solitary or in small groups disseminated along the river, revealing the poor health of the wild population.

Since 1981, close to 140 young originating from the Gharial Conservation Project were released in R.C.N.P. rivers (i.e. Rapti and Narayani rivers). Nevertheless, this can not stop wild population decline. In the past, the released gharials were monitored over a short period but there has been no proper monitoring since the departure of one of us (Dr T. Maskey). After our first expedition, we envisaged to monitor the next release gharials with telemetry.

Three months later (March 2002), 10 young gharials (2 males and 8 females) were measured, marked with notches and were implanted with Indexel® transponders furnished by Mérial (Table 1). They were also equipped with radio transmitters using an individual frequency. They were first placed into an acclimatisation enclosure close to Almatari island. One week later, gharials were released into the river.

With boat or perched on elephants, we followed during one month, the behaviour of the young gharials. Three individuals remained at proximity of the acclimatisation site. The 6 others went rapidly in different direction, up and down the river. 4 individuals seemed to let themselves be transported by the current and went further down stream in the direction of Tribeni ghat. By the end of Marsh, more than 25 kilometres separates the first crocodile from the last one!

With our presence not being continuous, we trained rangers of the D.N.P.W.C. and several guides of the Tiger Tops Jungle Lodge to keep on doing the monitoring after we had left. Our objective was to keep on locating each animal at least once a week. We hope to return twice a year (before and after the monsoon) during the two years equivalent of the life of the radio transmitters. The success of this long-term work will not bear its results until the gharial we released are fully-grown and breed in the wild.

Notch number	Sex	Weight (in kg)	Length (in cm)	Age (in years)
1	female	22	208	9
2	male	22,5	210	9
3	male	20,5	201	9
4	female	19	204	9
5	female	10	156	7
6	female	23,5	208	9
7	female	15,5	181	9
8	female	18	185	9
9	female	14,1	172	9
10	female	11	163	7

Table 1: Characteristics of the released gharials