The behaviours and night disturbances of the green turtle in Penang Island, Peninsular Malaysia

This paper focuses on the observation and behaviours of green turtles for one breeding season at Penang Island. Green turtle breeding behaviours and morphological characteristics were studied at Pantai Kerachut and Teluk Kampi, situated at Penang Island, the northern island of Peninsular Malaysia between December 2012 and August 2013. The findings revealed that from the eight green turtles landed; 106 were emergences, 38 were nests, and 158 digging attempts were made over the duration of one breeding season. The total clutch size deposited ranged from 170 to 979 eggs per turtle, and total nests ranged from three to eight nests per turtle. The inter-nesting interval ranged from 9 to 29 days, and the average was 13.5 days. Longer inter-nesting intervals were due to disturbances from feral dogs, wild pigs, sea-coated otters and night activities of fishermen (use of wide torch lights, sounds of boat engines) especially at Teluk Kampi. Lack of full-time personnel to control at Teluk Kampi was found to be a cause to nest poaching. Based on these findings and observation, the study suggests that Kerachut Turtle Conservation Centre should hire sufficient staffs to patrol the two beaches in order to prevent from human poachers and animal disturbances

Nesting Ecology Of The Green Turtle, Chelonia Mydas And Hawksbill Turtle, Eretmochelys Imbricata On The West Coast Of Peninsular Malaysia

Kedudukan geografi Pulau Pinang dan Melaka yang terletak di pantai barat Semenanjung Malaysia, merupakan lokasi penting untuk pendaratan penyu. Kajian telah dijalankan di kedua-dua lokasi ini, dan data taburan sarang penyu agar, Chelonia mydas di Pulau Pinang (dari tahun 2010 hingga 2014) dan penyu karah, Eretmochelys imbricata di Melaka (dari tahun 2013 hingga 2014) dibekalkan oleh Jabatan Perikanan Malaysia dengan kebenaran pihak Jabatan untuk menerbitkan keputusan kajian. Objektif kajian ini bertujuan untuk menentukan musim bersarang penyu agar di Pulau Pinang, menentukan kecenderungan pilihan ruang-masa (spatiotemporal) bagi sarang penyu karah di Melaka, menentukan tapak pemilihan sarang bagi penyu agar di Pulau Pinang, dan menentukan kajian keberjayaaan penetasan menggunakan Kaedah Rekaan Pecahan Telur. Jumlah sebanyak 265 sarang penyu agar telah dikenalpasti terdapat di Pulau Pinang dalam tempoh lima tahun (2010-2014). Jumlah sarang tertinggi dikenalpasti tertumpu di Kerachut, dan jumlah sarang kedua tertinggi dikenalpasti di Teluk Kampi, diikuti oleh Teluk Aling, Teluk Duyung, dan Pasir Pandak. The geographic locations of Penang Island and Melaka along the west coast of Peninsular Malaysia provide important nesting beaches for marine turtle nesting. A study was conducted at these two nesting beaches, and nesting data of the green turtle, Chelonia mydas in Penang Island (from 2010 until 2014) and hawksbill turtle, Eretmochelys imbricata in Melaka (from 2013 until 2014) was supplied by the Department of Fisheries, and permission granted to publish the results. The objectives of the study were to determine the seasonality of green turtle nesting in Penang Island, spatiotemporal preferences in nesting of hawksbill turtle in Melaka, nest site selection of green turtle in Penang Island, and hatching success of green turtle by using a Split Clutch Design Method. A total of 265 green turtle nests were identified in Penang Island within a five-year period (2010-2014). The highest number of nests was observed at Kerachut, and the second highest total was observed at Teluk Kampi, followed by Teluk Aling, Teluk Duyung, and Pasir Pandak

Distribution, abundance, and clutch size of hawksbill turtle nests in Melaka, Malaysia

The nesting of hawksbill turtle (Eretmochelys imbricata) was monitored from 2006 until 2014, while the eggs survival was monitored from 1990 until 2014 at the beaches of Melaka, Peninsular Malaysia. From 2006 until 2014, the yearly nesting ranged from 353 to 568 nests with a mean of 431.6 (n=9). Among the 21 recognized nesting beaches, five of the main beaches that included Padang Kemunting (55-107 nests), Pulau Upeh (36-111 nests), Kem Terendak (31-98 nests), Pasir Gembur (28-59 nests), and Tanjung Serai (14-60 nests) recorded the highest nesting in Melaka. Yearly number of live hatchlings ranged from 27.9% to 81.4% from 1990 until 2014. In 25 years, the overall number of live hatchlings produced was 491,643 hatchlings (53.4%) from 920,996 eggs. Hawksbill turtle eggs ranged from 9 to 212 eggs from the observation in 2013 and 2014, and most of the clutch sizes were deposited in a group of 121-150 eggs (36.2% observations). This study provides basic knowledge on the distribution and number of hawksbill turtle for a period of 25 years in Melaka; besides providing suggestion and recommendations to the conservation of this endangered species

Temperature influence on emergence success and swimming speed for In-situ nesting for Chelonia mydas in Penang Island, Malaysia

The study was performed in Penang Island, Malaysia from October 2013 to March 2015. This is the first study performed by using the In-situ incubation method, and the eggs were incubated naturally at Kerachut. As the In-situ procedure is not advisable to be performed due to risk from eggs poachers and predator disturbance, only nine nests were incubated. Three objectives were formulated; First, to determine the influence of sand temperature on the hatching success and emergence success. Second, to evaluate the effects of sand temperature on hatchlings swimming speed, and third, to observe the pattern of hatchling emergence between day-time and night-time. The result shows that there is significant correlation between hatching success and emergence success on the sand temperature, and also a significant correlation between sand temperature and swimming speed. Furthermore, the study identified that the hatchling emerges during night-time rather than day-time, and the percentage was 94.18%, 80.67, and 78.05%, based on observation from Day 1 until Day 3. The overall mean hatchlings straight carapace length was 40.80 mm±5.08, mean hatchlings straight carapace width was 31.78 mm±4.55, and mean hatchlings weight was 20.5 g±1.22. For future conservation, first, the sample size of In-situ nests is suggested to be increased because the result from the study provides a new knowledge, and widens the scope of the research by including the study on hatchlings locomotors performance (crawling performance and self-righting performance). Second, additional study on the relationship between surroundings water temperatures on the swimming speed performance is also suggested. This paper provides basic knowledge for the first research of In-situ nesting in Penang Island, and the recommendation may benefit the management of the Kerachut Turtle Conservation Centre

Importance of sand particle size and temperature for nesting success of green turtles in Penang Island, Malaysia

The microhabitats of green turtle (Chelonia mydas) nests were investigated to identify key factors influencing nesting success by monitoring both successful nests (n = 43) and aborted nests (n = 106) created by the same individuals (n = 9) from September 2013 to September 2014 on Penang Island, Malaysia. The effect of sand particle size on nesting success was significant, suggesting that green turtles tend to abort nesting at sites with sands of particle sizes < 1 mm. In addition, nests were successful at superficial sand temperatures less than 32.95°C

Reproductive seasonality and environmental effects in green turtle (Chelonia mydas) nesting at Penang Island, Malaysia

For species with environmental sex determination, understanding the relationship between reproduction and environmental factors is important for predicting their reproductive output. Here, we study intra-annual variation in green turtle nesting during the 2010-2016 seasons at Penang Island (5°16′28″-5°28′15″N 100°10′52″-100°11′55″E), Malaysia. The additive modelling on a monthly-basis number of nests shows that fluctuation in the number of nests relates to temperature in addition to month of year, rather than precipitation. The number of nests tended to be higher in response to higher temperature during March-July, whereas the lower temperature during August-February also tended to result in a relatively higher number of nests. Concentration of nests during March-July resulted from a shorter inter-nesting interval during warm temperatures, whereas relatively low temperatures may homogenize the temporal distribution of the number of nests. This study provides fundamental information for green turtle nesting seasonality in response to environmental change

Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

Turtles in Malaysia: a review of conservation status and a call for research

Approximately 356 species of turtles inhabit saltwater and freshwater habitats globally, except in Antarctica. Twenty-four species of turtles have been reported in Malaysia, four of which are sea turtles. The state of Terengganu harbored the highest number of turtles, with 17 different reported species. Based on the IUCN Red List, 29% of turtle species in Malaysia are critically endangered. In comparison, another 25% are classified as endangered. Likewise, CITES reported that 67% of Malaysia’s turtles are threatened, while 25% are classified as critically endangered. This review discusses the checklists, molecular genetics work, conservation status, recent trends, and recommendations for future research. Factors contributing to their population declines and current endangered status are also discussed

Turtles in Malaysia: A Review of Conservation Status and a Call for Research

Approximately 356 species of turtles inhabit saltwater and freshwater habitats globally, except in Antarctica. Twenty-four species of turtles have been reported in Malaysia, four of which are sea turtles. The state of Terengganu harbored the highest number of turtles, with 17 different reported species. Based on the IUCN Red List, 29% of turtle species in Malaysia are critically endangered. In comparison, another 25% are classified as endangered. Likewise, CITES reported that 67% of Malaysia’s turtles are threatened, while 25% are classified as critically endangered. This review discusses the checklists, molecular genetics work, conservation status, recent trends, and recommendations for future research. Factors contributing to their population declines and current endangered status are also discussed

Assessing nesting status of green turtles, Chelonia Mydas in Perak, Malaysia

The nesting of green turtle (Chelonia mydas) was monitored from 1998 untill 2013 along the beaches of Pasir Panjang, Segari, Perak. The objective of the study is to assess the nesting status of green turtles in Perak, Peninsular Malaysia in terms of total nests,eggs, survival hatchings, and density of visitors. A total number of green turtle nests foundfor 16 years were 1,019 nests and varied from 10 to 220 nests per year. Meanwhile, the sum of eggs collected for 16 years were 107,820 eggs, and varied from 553 to 20,881 eggs per year. The temporal pattern of nesting indicates year-round nesting in Perak in most years within the 16 years period. The peak season of nesting was estimated to occur between May and June. Survival hatchlings varied from 23.33% (2,071 hatchlings) to 55.03% (5,018 hatchlings) from 1998 to 2013. The density of visitors was not uniformly distributed among the years, and shows a sign of decline especially from 2006 onwards. This publication provides basic knowledge of green turtle nesting population in Perak, and would be helpful in upgrading the conservation program in Malaysia. In future, we hope 1) for an increase in manpower to obtain accurate nesting records along the nesting beaches during nocturnal survey and, 2) to include the breeding biology data such as nest placement, emergence hour, and morphological characteristics of green turtle. Sarang penyu agar (Chelonia mydas) di pantau dari tahun 1998 hingga 2013 di sepanjang pantai Pasir Panjang, Segari, Perak. Objektif kajian ini ada untuk melihat status bersarang penyu agar di Perak, Semenanjung Malaysia dari sudut kajian jumlah sarang, telur, survival anak penyu, dan kepadatan pelawat. Jumlah sarang penyu agar yang di jumpai dalam tempoh 16 tahun adalah sebanyak 1,019 sarang, dan berbeza dari 10 hingga 220 sarang setiap tahun. Sementara itu, jumlah telur yang dikutip dalam tempoh 16 tahun adalah sebanyak 107,820 telur, dan berbeza dari 553 hingga 20,881 telur setiap tahun. Corak temporal menunjukkan Perak mempunyai taburan sarang di sepanjang tahun di kebanyakan tahun dalam tempoh 16 tahun. Musim kemuncak waktu bersarang dijangkakan berlaku di antara Mei dan Jun. Survival anak penyu berbeza dari 23.33% (2,071 anak penyu) hingga 55.03% (5,018 anak penyu) dari tahun 1998 hingga 2013. Kepadatan pelawat adalah tidak seragam antara tahun, dan menunjukkan penurunan terutamanya dari tahun 2006 dan ke atas. Penerbitan ini mengetengahkan ilmu asas berkaitan populasi sarang penyu agar di Perak, dan mungkin berguna ke arah meningkatkan program pemuliharaan di Malaysia. Di masa hadapan, kami mengharapkan 1) peningkatan jumlah tenaga pekerja semasa tinjauan di waktu malam di sepanjang pantai bersarang untuk ketepatan rekod catatan, dan 2) mengetengahkan maklumat biologi pembiakan seperti lokasi penempatan sarang, masa pendaratan, dan ciri-ciri morfologi penyu agar