Post-emergence handling of green turtle hatchlings: improving hatchery management worldwide J. P. van de Merwe, 1 * K. Ibrahim 2† & J. M. Whittier 1‡ 1 School of Biomedical Sciences, University of Queensland, St Lucia, Qld, Australia 2 Turtle and Marine Ecosystems Centre, Department of Fisheries Malaysia, Rantau Abang, Terengganu, Malaysia Keywords hatchling quality; hatchling condition; running speed; artificial lighting; sea-finding ability; Malaysia. Correspondence Jason Paul van de Merwe, Australian Rivers Institute, Griffith University, Gold Coast, Qld 4222, Australia. E-mail: jpvanders@hotmail.com Current addresses: *Australian Rivers Institute, Griffith University, Gold Coast, Qld, Australia † Marine Park Department of Malaysia, Ministry of Natural Resources and Environment, Federal Government Administration Centre, Putrajaya 62602, Malaysia ‡ School of Medicine, University of Tasmania, Hobart, Tas. 7001, Australia Editor: Trent Garner Associate Editor: Mariana Morando Received 26 October 2011; accepted 11 September 2012 doi:10.1111/j.1469-1795.2012.00603.x Abstract Hatcheries are commonly used to protect sea turtle eggs from poaching and predation; however, there is currently limited scientific evidence to support good hatchery management practices, particularly post-hatching. This study investi- gated the effects of retaining hatchlings in hatcheries after emergence and delaying nest excavations on the quality of green turtle Chelonia mydas hatchlings. In addition, the effect of artificial lighting on the sea-finding ability of green turtles was investigated to highlight the importance of hatchling release locations on hatchery beaches. Hatchling running speed, an indicator of vigour and predation exposure, progressively decreased when hatchlings were retained in the hatchery for 1, 3 and 6 hours following emergence. Similarly, body condition (mass : straight carapace length), an indicator of dehydration and/or energy consumption, decreased after being retained for 3 and 6 hours. It was estimated that hatchlings retained for 6 hours after emergence would become significantly dehydrated and double their exposure to beach slope predation. Residual hatchlings that were immediately excavated from emerged nests had similar running speed and body condition to naturally emerged siblings. However, residual hatchlings removed from nests 5 days later had significantly reduced running speed and body condi- tion, resulting in estimates of double the exposure to predation in near-shore areas. The mean angle of hatchling dispersal varied at different sites along the Ma’Daerah beach in relation to proximity to artificial lighting. Important recom- mendations for post-hatching management of sea turtle hatcheries worldwide can be made from the results of this study. To maximize release of hatchlings in the best condition as is possible, hatchlings should be released immediately after emergence, including excavation of any residual hatchlings. In addition, the dis- persal angles of hatchlings should be tested at each hatchery beach to determine suitable release sites for efficient dispersal. Introduction Anthropogenic activities have had significant impacts on sea turtle populations worldwide, resulting in all species (except the flatback Natator depressus, which is ‘data deficient’) being listed as vulnerable, endangered or critically endan- gered by the International Union for Conservation of Nature (IUCN, 2011). The use of semi-enclosed beach hatcheries is a common management strategy for the pro- tection of sea turtle eggs threatened by poaching and pre- dation (Mortimer, 1999). However, the movement of sea turtle eggs from natural nests to hatcheries can increase the risks of embryonic mortality (Limpus, Baker & Miller, 1979) and create a nest environment less suitable for hatch- ling incubation and emergence (Blanck & Sawyer, 1981; Billett et al., 1992; van de Merwe, Ibrahim & Whittier, 2005). There is therefore a current need for experiments that critically evaluate hatchery procedures. While there have been a number of studies detailing egg collection/handling techniques and hatchery design (Table 1), the post- emergence handling of hatchlings has received limited atten- tion in the literature to date. Such information is crucial for successful hatchery management worldwide. Sea turtle hatcheries are typically constructed on nesting beaches so that clutches can be relocated for protection with minimal transport and disturbance (Fig. 1). They are wooden structures that are fully enclosed by shade cloth to protect them from poaching and predation, and to main- tain temperatures within suitable ranges for hatchling development (van de Merwe, Ibrahim & Whittier, 2006). Within the hatcheries, a circular mesh fence is placed around the periphery of each relocated nest to collect hatchlings following emergence so they can be easily counted and released. Animal Conservation. Print ISSN 1367-9430 316 Animal Conservation 16 (2013) 316–323 © 2012 The Zoological Society of London