CSIRO PUBLISHING www.publish.csiro.au/journals/wr UlildlifeResearch,2009,36,637-645 Habitat use by green turtles (Chelonia mydas) nesting in Peninsular Malaysia: local and regional conservation implications Jason Paul van de MerweA.B,G, Kamarruddin IbrahimC,D, Shing Yip Lee A andJoan Margaret WhittierE,F AGriffith School of Environment and Australian Rivers Institute, Griffith University (Gold Coast), Griffith University, QLD 4222, Australia. Bpresent address: Centre for Marine Environmental Research and Innovative Technology, City University of Hong Kong, Hong Kong SAR, China. CTurtle and Marine Ecosystems Centre, Department of Fisheries Malaysia, Rantau Abang, Terengganu, Malaysia. Dpresent address: Marine Park Department of Malaysia, Ministry of Natural Resources and Environment, Federal Government Administration Centre, Putrajaya, Malaysia. ESchool of Biomedical Sciences, University of Queensland, St Lucia, QLD 4067, Australia. Fpresent address: School of Medicine, Locked Bag 24, University ofTasmania, Sandy Bay, Tas. 7005, Australia. GCorresponding author. Email: [email protected] Abstract Context. Many green sea turtle (Chelonia mydas) populations are declining worldwide owing to their susceptibility to human impacts in the marine environment. Identifying the habitats used throughout different lifecycle stages is therefore important for managing the interactions between turtles and humans. Aims. To identify the habitat utilisation of a C. mydas nesting population in Peninsular Malaysia during breeding, inter-nesting, migration and foraging lifecycle stages. Methods. Satellite telemetry was used to track the movement ofthree C. mydas nesting females and one adult male from the Ma'Daerah rookery (Peninsular Malaysia). Key results. The male and female turtles remained within 30 km ofthe nesting beach during the breeding and inter-nesting periods, which includes habitat beyond the 'no trawl zone' designed to protect turtles in this area. Following the breeding season, the tracked turtles migrated up to 1955 km to four ditTerent foraging grounds in Vietnam, Indonesia, Peninsular Malaysia and Bomeo Malaysia. During foraging, turtles occupied areas threatened by human activities such as fishing and pollution. Conclusions. The habitats used by the Ma'Daerah C. mydas population during breeding are outside current local protection zones and extend into unprotected international waters during migration and foraging. Implications. Identification of habitats used by C. mydas populations is a critical element of management and conservation of this endangered, migratory species. Our study highlights the need to increase offshore protection around Ma'Daerah during the nesting season. Furthermore, this study has identified the countries within South-east Asia that Malaysia must cooperate with to ensure effective management ofthis C. mydas population. This infonnation is particularly relevant to sea turtle conservation and management in regions like South-east Asia, where many coastal countries occupy a small geographical area. Additional keywords: breeding, foraging, migration, satellite telemetry. Introduction result, many sea turtle populations are declining worldwide Sea turtles inhabit a range of oceanic and neritic environments and all species (except the flatback (Natator depresslls), which throughout their lifecycle (Miller 1997). Within these habitats, is listed as 'Data Deficient') have been listed as 'Endangered' sea turtles are exposed to anthropogenic impacts, such as or 'Critically Endangered' by the International Union for incidental capture in fishing gear, boat strikes and harvesting Conservation of Nature (IUCN 2007). Sea turtles are also (Hutchinson and Simmonds 1992; Poiner and Harris 1996). As a listed in Appendix 1 of the Convention of International Trade © CSIRO 2009 10.1071/WR09099 1035-3712/09/070637 638 Wildlife Research J. P. van de Merwe et al. of Endangered Species of Wild Fauna and Flora (CITES). areas (Bowen et al. 1992; Fitzsimmons et al. 1996). This Understanding habitat utilisation of sea turtles is therefore implies that each breeding C. mydas population must be important for managing and conserving endangered populations. treated as an independent management unit when considering The Ma'Daerah Turtle SanctuaJ)', on the east coast of threats and conservation. In addition, effective management of Peninsular Malaysia, supports a large breeding population of a breeding population requires knowledge of the threats at green sea turtles (Chelonia myda.v). However, this population the different foraging grounds and along the migration routes. has declined by >SO% since the 1950s, primarily owing to the This is complicated by the fact that foraging areas can be long collection of eggs for human consumption, nesting beach distances from the breeding areas and are often located in other development and the incidental capture of turtles in fishing countries with varying conservation ethics, regulations and gear (Ibrahim 1994). The current management of this resources. population involves the use of hatcheries on the nesting Satellite telemetry has previously been used to track the beaches to protect the eggs from collection and a 'no trawl movement of C. mydas in foraging habitats and along zone', which extends 5.5 nautical miles (-10 km) offshore migration routes (see Tables I, 2). However, there is limited from the nesting sites (Fisheries Act 1985, Malaysia) to information in the literature on the habitats used by C. mydas protect turtles in the marine environment. However, there is for breeding (courtship and mating) or the areas used by nesting currently no information on habitats used by this C. mydas females between laying subsequent clutches during the nesting population during breeding, inter-nesting, migration and foraging. season (inter-nesting habitat). FUlihermore, comprehensive C. mydas adults spend the majority of their lives in neritic studies encompassing all of the important habitats of a single foraging habitats, such as coastal seagrass meadows and nesting population are limited. The aim ofthe present study was reefs (Musick and Limpus 1997; Bjomdal et al. 2005). Sexually therefore to investigate the breeding, inter-nesting, migration mature C. mydas migrate seasonally to breeding grounds, which and foraging areas used by the Ma'Daerah C. mydas nesting are in their natal areas (Meylan et al. 1990; Bowen et al. 1992). population. This new information will assist in the management Females can remain in the nesting area for up to 6 months while and conservation of this endangered C. mydas population. they lay I-11 clutches at 2-week intervals (Miller 1997). During their reproductive years, C. myda.\· adults show strong fidelity to Materials and methods these foraging and breeding sites, which can be up to thousands of kilometres apart (Carr and Carr 1972; Limpus et al. 1992; Satellite transmitter attachment Lohmann et al. 1997). C. mydas individuals from a single Between 20 August and 9 September 2005, satellite foraging area may migrate to several different breeding areas, transmitters were attached to three C. mydas females nesting and a breeding population is often populated by individuals at the Ma'Daerah Toole Sanctuary (4°32'17"N, 103°2S'14"E) from a wide range of foraging areas (Liew et al. 1995; Cheng and one adult male captured in the cooling tanks of the YTL 2000; Godley et al. 2002; Seminoffet al. 200S). Therefore, threats Corporation's power station (4 C 35'26"N, J03°27'7"E) in Paka, to C. mydas in a foraging area can potentially affect several Terengganu, Peninsular Malaysia (Table 3). Kiwi Sat (0.5 W) different breeding populations and a single breeding population Platform Terminal Transmitters (PTTs) powered by two can be influenced by threats in several different foraging areas. lithium C cells (Sirtrack, Havelock North, New Zealand) were The strong fidelity to natal rookeries results in genetically attached to the carapace using methods modified from distinct populations being established around major breeding Balazs et al. (1996). Table 1. Summary of the distance (km), days tracked and speed (km h-') of Chelonia mydas post-nesting migrations, determined by satellite tracking studies N/A, not available Nesting site n Distance Days Speed Reference Ascension Island 5 1792-2346 33-47 1.9-2.8 Luschi et al. (1998); Hays et af. (1999) Ascension lslanda 2 N/A N/A 2.2-2.3 Hays et al. (2001 b) Japan 4 966--1962 28-42 1.4-2.1 Hatase et al. (2006) Taiwanb 8 193-1909 7-57 1.2-2.8 Cheng (2000) Hawaii/Samoa 5 110~1750 26-45 1.6-1.9 Balazs et ai. (1994) Hawaii 3 830-1260 22-26 1.6--2.0 Balazs (1994) Hawaii" 3 105~1200 23·30 1.7-1.9 Balazs and Ellis (2000) Costa Rica 10 4101470 1127 0.9-2.5 Troeng et ai. (2005) b d Cyprus • 6 3222199 843 1.62.1 Godley et al. (2002) Galapagos Islandsd 12 12171912 2652 1.12.2 Seminotf et al. (2008) Peninsular Malaysiab 5 669-1744 13-30 1.7-2.6 Liew et al. (1995) Peninsular Malaysia 4 310-1955 15-45 0.9-2.4 Present study aMale C. mydas only. ~ot all migrations completed to foraging areas. clncludes male C. mydas. dOverall inter-nesting, migration and foraging movement. Conservation implications of green turtle habitat use Wildlife Research 639 Table 2. Summary of foraging home ranges of Chelonia mydas in previous studies SCL, straight carapace length Site Turtles Mean Foraging area Reference 2 SCL (cm) range (km ) Mosquito Lagoon, FL. USA 9 <65 0.48~5.06 Mendonya (1983) Kaneohe Bay, HI, USA 12 51.3 2.62 ±0.96" Brill et al. (1995) South Padre Island, TX,