1FLAME University, Pune, Maharashtra, India
2Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India
3Dakshin Foundation, Bengaluru, India
#andrea.phillott@flame.edu.in
Papers in Issue 27 of the Indian Ocean Turtle Newsletter highlight the extent to which countries in South Asia use hatcheries as an ex situ conservation strategy. Hatcheries are often perceived as ‘safe’ places to incubate sea turtle nests. Depending on the hatchery location and construction, eggs may be protected from predators, poachers, tidal inundation, and beach erosion. Hatcheries may also be used to raise community awareness about the biology and need for conservation of sea turtles, and provide opportunities for community revenue through ecotourism.
However, there should be ongoing threats to eggs in the natural environment for nests to be moved to a hatchery, as there are disadvantages to this practice. Hatching success in hatchery nests may be far lower than that of natural nests on the beach if poor hatchery management practices are employed, and sex ratios of hatchlings can be skewed if the nest temperatures within a hatchery differ from those on the natural beach. Operating a hatchery following best practice guidelines requires trained personnel and sufficient resources to protect and monitor nests throughout the nesting season (Mortimer, 1999; Shanker et al., 2003).
Considering the disadvantages of incubating eggs in a hatchery, sea turtle nests should preferably remain in situ for the duration of the incubation period. Nests can be protected in their original location, for example, caged (Kurz et al., 2011) or meshed (e.g. O’Connor et al., 2017) to exclude predators, or relocated to a higher site on the beach if laid close to the high tide line (e.g. Tuttle & Rostal, 2010). Community awareness and conservation initiatives have proved successful at reducing the loss of nests to poachers (e.g. Rajakaruna et al., 2009; West, 2010),
However, if moving eggs to a hatchery will ensure a much higher hatching success than the strategies described above, then hatchery location and construction, methods of egg collection and transport, hatchery nest characteristics and density, and hatchling handling and release, should aim to maximise the number of hatchlings produced. Manuals relevant to the conservation of sea turtles in countries within the Indian Ocean and South East Asia (and globally) can be used as reference material for hatchery operations- Eckert et al. (1999), Ahmad et al. (2004) and SToI (2011). A visual summary of best practise for sea turtle hatchery management is available on the website Sea Turtles of India (https://www.seaturtlesofindia.org/library/outreach-material/). For quick reference, the best practices in hatchery management have been summarised in Table 1; references to studies that support the recommendations have also been provided.
We also recommend that hatchery managers periodically review the need for nests to be moved from their natural location, as changes in predator density and poaching activities may occur over time, removing the need for hatcheries to protect nests. Nests demonstrating a high hatching success and with a low risk of egg loss from depredation, poaching, tidal inundation, erosion, microbial invasion, etc should remain where they are laid.
Table 1. A summary of best management practices for sea turtle hatcheries.
Best Practice | Supporting Literature | |
Hatchery location |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004); Spanier (2010); Maulany et al. (2012) |
Hatchery construction
(incl shading) |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004) |
Egg collection |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004) |
Egg handling and transport |
|
Limpus et al. (1979); Parmenter (1980); Harry & Limpus (1989); Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004); Williamson et al, (2017) |
Reburial of nests |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004); van de Merwe et al. (2006); Rusli & Booth (2016) |
Nest density |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004); Maulany et al. (2012) |
Nest enclosures |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004) |
Hatching release |
|
Mortimer et al. (1999), Wyneken (2000); Pilcher & Enderby, 2001; Shanker et al. (2003), Ahmad et al. (2004); van de Merwe et al. (2013) |
Hatchery records |
|
Mortimer et al. (1999), Shanker et al. (2003), Ahmad et al. (2004) |
Monitoring and evaluation |
a) Hatching Success= (Number of hatched eggs/Total number of eggs) x 100 b) Emergence Success= (Number of naturally emerged hatchlings/Total number of eggs) x 100
|
Mortimer et al. (1999), Schäuble et al. (2002); Shanker et al. (2003) |
Education and awareness |
|
Shanker et al. (2003) |
Personnel |
|
Shanker et al. (2003) |
Ahmad, A., T. Zulkifli, M.I. Mahyam, A.R. Solahuddin & Z. Nor Azman. 2004. A Guide to Set-Up and Manage Sea Turtle Hatcheries in the Southeast Asian Region. Marine Fisheries Resources Development and Management Department and Southeast Asian Fisheries Development Center (SEAFDEC).
Harry, J.L. & C.J. Limpus. 1989. Low-temperature protection of marine turtle eggs during long-distance relocation. Australian Wildlife Research 16: 317-320.
Limpus, C.J., V. Baker & J.D. Miller. 1979. Movement induced mortality of loggerhead eggs. Herpetologica 35: 335-338.
Maulany, R.I., D.T. Booth & G.S. Baxter. 2012. The effect of incubation temperature on hatchling quality in the olive ridley turtle, Lepidochelys olivacea, from AlasPurwo National Park, East Java, Indonesia: Implications for hatchery management. Marine Biology 159: 2651–2661.
Mortimer J.A. 1999. Reducing threats to eggs and hatchlings: Hatcheries. In: Research and Management Techniques for the Conservation of Sea Turtles (eds. Eckert, K.L., K.A. Bjorndal, F.A. Abreu-Grobois & M. Donnelly). Pp 175-178. IUCN/SSC Marine Turtle Specialist Group Publication No. 4.
O’Connor, J.M., C.J. Limpus, K.M. Hofmeister, B.L. Allen & S.E. Burnett. 2017. Anti-predator meshing may provide greater protection for sea turtle nests than predator removal. PloS ONE 12: e0171831.
Parmenter, C.J. 1980. Incubation of the eggs of the green sea turtle, Chelonia mydas, in Torres Strait, Australia: The effect of movement on hatchability. Australian Wildlife Research 7: 487-91.
Pilcher, N.J. & S. Enderby. 2001. Effects of prolonged retention in hatcheries on green turtle (Chelonia mydas) hatchling swimming speed and survival. Journal of Herpetology 35: 633-663.
Rajakaruna, R.S., D.M.Naveen, J. Dissanayake, E.M.L. Ekanayake & K.B. Ranawana. 2009. Sea turtle conservation in Sri Lanka: Assessment of knowledge, attitude and prevalence of consumptive use of turtle products among coastal communities. Indian Ocean Turtle Newsletter 10: 1-13.
Rusli, M.U. & D.T. Booth. 2016. Bigger clutch sizes save offspring energy during nest escapes. Behavioral Ecology and Sociobiology 70: 607-616.
Schäuble, C., K. Ibrahim, A.R. Kassim, M. Hamann, & J. Whittier. 2002. Monitoring hatchery success– What’s worthwhile? In: Proceedings of the 22nd Annual Symposium on Sea Turtle Biology and Conservation. (comp. Seminoff, J.A.). NOAA Technical Memorandum NMFS-SEFSC-503, 308 p.
Sea Turtles of India (SToI). 2011. A Comprehensive Field Guide to Research, Monitoring and Conservation (comps. Shenoy, S., T. Berlie & K. Shanker). Dakshin Foundation, Bangalore and Madras Crocodile Bank Trust, Mamallapuram, India. Pp. 148.
Shanker, K., B.C. Choudhury & H.V. Andrews. 2003. Sea Turtle Conservation: Beach Management and Hatchery Programmes. A GOI-UNDP Project Manual. Centre for Herpetology/Madras Crocodile Bank Trust, Mamallapuram, Tamil Nadu, India.
Spanier, M.J. 2010. Beach erosion and nest site selection by the leatherback turtle Dermochelys coriacea (Testudines: Dermochelyidae) and implications for management practices at Playa Gandoca, Costa Rica. Revista de Biología Tropica 58: 1237-1246.
Tuttle, J. & D. Rostal. 2010. Effects of nest relocation on nest temperature and embryonic development of loggerhead sea turtles (Caretta caretta). Chelonian Conservation and Biology 9: 1-7.
van de Merwe, J., K. Ibrahim & J. Whittier. 2006. Effects of nest depth, shading, and metabolic heating on nest temperatures in sea turtle hatcheries. Chelonian Conservation and Biology 5: 210-215.
van de Merwe, J.P., K. Ibrahim & J. M. Whittier. 2013. Post-emergence handling of green turtle hatchlings: Improving hatchery management worldwide. Animal Conservation 16: 316–323.
West, L. 2010. A multi-stakeholder approach to the challenges of turtle conservation in the United Republic of Tanzania. Indian Ocean Turtle Newsletter 11: 44-50.
Williamson S.A., R.G. Evans & R.D. Reina. 2017. When Is embryonic arrest broken in turtle eggs? Physiological and Biochemical Zoology 90: 523–532.
Wyneken, J. 2000. The migratory ehaviour of hatchling sea turtles beyond the beach. In: Sea Turtles of the Indo-Pacific. (eds. Pilcher, N.J. & G. Ismail). Pp 121–142. ASEAN Academic Press, London.
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