Growth rate of captive Gharials Gavialis gangeticus (Gmelin, 1789) (Reptilia: Crocodylia: Gavialidae) in Chitwan National Park, Nepal

Main Article Content

Bed Bahadur Khadka
Ashish Bashyal
https://orcid.org/0000-0002-2030-4509

Abstract

Gharials Gavialis gangeticus have been reared in ex situ facilities in the Gharial Conservation and Breeding Center (GCBC) in Chitwan National Park of Nepal since the 1980s.  There remains a paucity of detailed information concerning their growth rates, particularly with respect to season.  We randomly selected 20 gharials (45 months old) in the GCBC, tagged them, and recorded total length (TL) and weight over three warm (April–September) and two cold (October–March) seasons between 01 April 2013 and 30 September 2015.  We also recorded amounts of fish consumed by these gharials every month over the 30-month period.  On average per season, the gharials grew by 9.48±3.63 cm (1.58cm/month) in length and gained 2.61±1.14 kg (0.43kg/month).  Growth rates were significantly higher during warm seasons.  The highest increase in both length (mean= 21.2±8.61 cm) and weight (mean =5.59±2.12 kg) occurred during the first warm season (April 2013–September 2013) of the study, and annual growth rate was also highest during the first year.  Our data indicated strong correlation between mean length and body weight.  A total of 2,103.9kg fish was consumed by 20 gharials over 30 months, for a mean consumption of 3.5kg fish per individual per month.  Mean fish consumption was also significantly higher during warm (96.99±37.35 kg) versus cold (29.83±17.09 kg) seasons.  Survival rate was 100%.  Our findings establish baseline data for growth and feeding rates of captive gharials that will be useful in making management decisions in captive breeding and rearing facilities.

Article Details

How to Cite
[1]
Khadka, B.B. and Bashyal, A. 2019. Growth rate of captive Gharials Gavialis gangeticus (Gmelin, 1789) (Reptilia: Crocodylia: Gavialidae) in Chitwan National Park, Nepal. Journal of Threatened Taxa. 11, 15 (Dec. 2019), 14998–15003. DOI:https://doi.org/10.11609/jott.5491.11.15.14998-15003.
Section
Communications
Author Biographies

Bed Bahadur Khadka, Gharial Conservation and Breeding Center, Chitwan National Park, Kasara, Chitwan, Nepal.

Bed Bahadur Khadka is Assistant Conservation Officer and In-charge of Gharial Conservation and Breeding Center at Chitwan National Park. He has wide experience in wetland and freshwater ecology and has been studying Gharials for last 15 years.

Ashish Bashyal, Biodiversity Conservancy Nepal, Manigram, Rupandehi 32903, Nepal.

Ashish Bashyal is a Co-founder and Conservation Scientist at Biodiversity Conservancy Nepal — a non-profit dedicated to wildlife conservation in Nepal. He has been studying genetics and ecology of crocodilians including Gharials since 2009.

References

Balaguera-Reina, S. A., M. Venegas-Anaya, O.I. Sanjur, H.A. Lessios & L.D. Densmore (2015). Reproductive ecology and hatchling growth rates of the American Crocodile (Crocodylus acutus) on Coiba Island, Panama. South American Journal of Herpetology 10: 10–23.

Ballouard, J.M., P. Priol, J. Oison, A. Ciliberti & A. Cadi (2010). Does reintroduction stabilize the population of the critically endangered Gharial (Gavialis gangeticus) in Chitwan National Park, Nepal? Aquatic Conservation: Marine and Freshwater Ecosystems 20: 756–761.

Barrios-Quiroz, G., G. Casas-Andreu & A.H. Escobedo-Galván (2012). Sexual size dimorphism and allometric growth of Morelet’s crocodiles in captivity. Zoological Science 29(3): 198–204. https://doi.org/10.2108/zsj.29.198

Fellows, I. (2012). Deducer: A Data Analysis GUI for R. Journal of Statistical Software 49(8): 1-15. http://www.jstatsoft.org/v49/i08/

Gorzula, S. & A.E. Seijas (1989). The Common Caiman, pp. 44–61. In: Crocodiles: their ecology, management and the conservation. IUCN, Gland, Switzerland, 308pp.

Joanen, T. & L. McNease (1987). Alligator farming research in Louisiana, USA, pp. 329–340. In: Webb G.J.W., S.C. Manolis & P.J. Whitehead (eds.). Wildlife Management: Crocodiles and Alligators. Surrey Beatty & Sons, Sydney, Australia, 552pp.

Khadka, B.B. (2010). Gharial hatching status in 2010, Chitwan National Park, Nepal. Crocodile Specialist Group Newsletter 29(3): 16–17.

Khadka, B.B. (2013). Effect of weather on hatching success of Gharial in Chitwan National Park. Crocodile Specialist Group Newsletter 32(4): 5–7.

Lang, J.W., S. Chowfin & J.P. Ross (2019). Gavialis gangeticus. The IUCN Red List of Threatened Species 2019: e.T8966A3148543; https://doi.org/10.2305/IUCN.UK.2019-1.RLTS.T8966A3148543.en

Maskey, T.M. (1989). Movement and survival of captive-reared gharials, Gavialis gangeticus, in the Narayani river, Nepal. Ph.D. Dissertation, University of Florida, USA, xiv+187pp.

R Core Team (2018). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.

Saalfeld, D.T., K.K. Webb, W.C. Conway, G.E. Calkins & J.P. Duguay (2008). Growth and Condition of American Alligators (Alligator mississippiensis) in an Inland Wetland of East Texas. Southeastern Naturalist 7(3): 541–550. https://doi.org/10.1656/1528-7092-7.3.541

Stevenson, C. & R. Whitaker (2010). Indian Gharial Gavialis gangeticus, pp. 139–143. In: Manolis, S.C. & C. Stevenson (eds). Crocodiles: Status Survey and Conservation Action Plan. Crocodile Specialist Group, Australia, 143pp.

Thorbjarnarson, J. B. (1988). The status and ecology of the American crocodile in Haiti. Bulletin of the Florida State Museum, Biological Sciences 33: 1–86.

Webb, G.J.W., H. Messel, J. Crawford & M.J. Yerbury (1978). Growth rates of Crocodylus porosus (Reptilia: Crocodilia) from Arnhem Land, Northern Australia. Australian Wildlife Research 5: 385–399. https://dx.doi.org/10.1071/WR9780385