Gangguan visual di kalangan kanak-kanak boleh menjadi serius tanpa intervensi awal. Kajian ini bertujuan untuk mengenal pasti prevalens penyebab kepada impairmen visual di kalangan kanak-kanak prasekolah. Sebanyak 21 buah tadika telah dipilih secara rawak untuk menjalani saringan penglihatan. Modul saringan penglihatan meliputi ujian akuiti visual, ujian katup, ujian Hirschberg, pemeriksaan mata luaran dan oftalmoskopi. Kanak-kanak yang gagal saringan penglihatan telah dirujuk untuk pemeriksaan lanjutan. Seramai 479 orang kanak-kanak dengan purata umur 5.30 ± 0.69 tahun telah mengambil bahagian dalam saringan penglihatan. Daripada 43 orang kanak-kanak yang gagal saringan penglihatan, 32 orang (6.7%) disahkan mempunyai gangguan visual. Manakala 8 orang didapati tidak mempunyai gangguan visual dan tiga orang digugurkan daripada kajian kerana tidak bekerjasama untuk pemeriksaan lanjutan. Ralat refraksi (5.8%) adalah penyebab utama kepada gangguan visual di kalangan kanak-kanak prasekolah. Penyebab-penyebab lain ialah ambliopia (1.3%), strabisms (1.0%) dan keabnormalan okular (0.8%). Pengesanan gangguan visual di peringkat awal melalui saringan penglihatan dan intervensi awal optometri adalah penting untuk dilaksanakan di kalangan kanak-kanak prasekolah supaya prevalens gangguan visual dapat dikurangkan.
Lemah konvergens (CI) adalah anomali penglihatan binokular yang melibatkan kesukaran dua mata menumpu semasa penglihatan dekat. Kajian ini mengkaji prestasi penglihatan binokular subjek CI. Prestasi binokular iaitu, akuiti penglihatan (VA) binokular jauh, VA binokular dekat dan stereoakuiti dibandingkan antara subjek CI dengan subjek normal. Seramai 30 subjek CI purata umur 17.33 ± 5.49 tahun dan 30 subjek normal purata umur 18.77 ± 6.08 tahun mempunyai VA 6/6 atau lebih baik, ralat refraksi sfera tidak melebihi ± 4.00 DS, astigmatisme tidak lebih daripada 2.00 DC, tiada juling dan tidak pernah menjalani terapi penglihatan, mempunyai kesihatan am dan kesihatan okular yang baik mengambil bahagian dalam kajian ini. VA monokular mata kanan, VA monokular mata kiri, VA binokular dan stereoakuiti dua kumpulan subjek diukur dan dibandingkan. Keputusan kajian mendapati perbezaan yang signifikan bagi VA binokular jauh (t = 2.31, p < 0.05), VA binokular dekat (t = 0.89, p < 0.05) dan stereoakuiti (Z = -2.81, p < 0.01) antara subjek CI dengan subjek normal. Kesimpulan kajian menunjukkan subjek kumpulan CI mengalami penurunan prestasi penglihatan binokular jauh, prestasi penglihatan binokular dekat dan stereoakuiti yang signifikan lebih rendah berbanding kumpulan normal.
Climate change is a clear and present threat to species survival. For species with temperature-dependent sex determination, including all sea turtles, it has been hypothesised that climate change may drive the creation of sex-ratio biases leading to population extinctions1. Through a global analysis across multiple species, we present the first direct empirical evidence for a demographic consequence of male scarcity in sea turtle populations, with a lower incidence of multiple paternity being found in populations with more extreme female-biased hatchling sex-ratio skews. For green turtles, when the female bias in hatchling sex ratio was >90%, the incidence of multiple paternity was low compared to other nesting sites, being 24.5% in the eastern Mediterranean (Cyprus), 36.4% on Redang Island (Malaysia) and 15.4% on the southern Great Barrier Reef (Heron Island, Australia) compared to higher values (range 61.1-91.7%) at other sites globally. These results suggest that a low incidence of multiple paternity may serve as a harbinger of future problems with egg fertility if males become even scarcer. Assessments of the incidence of multiple paternity at sites where adult males are expected to become scarce, such as Raine Island on the northern Great Barrier Reef in Australia, may help to identify when a lack of males raises the threat of local extinctions. In such cases, intervention to increase the production of male hatchlings may be needed.
Environmental DNA detection has emerged as a powerful tool to monitor aquatic species without the need for capture or visual identification and is particularly useful for rare or elusive species. Our objective was to develop an eDNA approach for detecting the southern river terrapin (Batagur affinis) in Malaysia. We designed species-specific primers for a fragment of B. affinis mtDNA and evaluated their effectiveness in silico, in vitro and in situ. The primers amplified 110 bp of the cytochrome b mtDNA sequence of B. affinis from aquarium water samples housing nine juvenile B. affinis. We also successfully detected B. affinis eDNA from river samples taken from a site where turtles were known to be in the vicinity. Prospects and challenges of using an eDNA approach to help determine the distribution of B. affinis, essential information for an effective conservation plan, are discussed.
For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures. In many egg-laying animals, parental care of the offspring may continue while the eggs are incubating and also after they have hatched. Consequently, the importance of the nest site for determining incubation conditions may be reduced since the parents themselves may alter the local environment. By contrast, in marine turtles, parental care ceases once the eggs have been laid and the nest site covered. The positioning of the nest site, in both space and time, may therefore have profound effects for marine turtles by affecting, for example, the survival of the eggs and hatchlings as well as their sex (Janzen and Paukstis 1991). During incubation, sea turtle embryos grow from a few cells at oviposition to a self-sufficient organism at hatching some 50-80 days later (Ackerman 1997). After hatching, the young turtles dig up through the sand and emerge typically en masse at the surface 1-7 nights later, with a number of stragglers following over the next few nights (Christens 1990). This contrasts with the frequently observed pattern of hatching asynchrony in birds. It has been suggested that the cause of mass emergence in turtles is that eggs within a clutch are fertilised within a short period of time and then, when thermal conditions within the nest are uniform, develop at very similar rates and hence hatch and emerge together (Porter 1972). As a corollary of this idea, it would be predicted that when there are pronounced within-nest thermal gradients, development rates of siblings will be different and hence asynchronous hatching and emergence might occur. While it may be energetically beneficial for hatchlings to emerge in a group (Carr and Hirth 1961), if the extent of hatching asynchrony is marked then there may be severe costs for individuals if they wait for all their siblings to hatch before attempting to dig out of the sand (Hays and Speakman 1992). Under such conditions, the protracted emergence of small groups of hatchlings over several nights may be favoured. Examination of the literature suggests that emergence asynchrony may be more widespread than generally considered. For example, Witherington et al. (1990) described loggerhead turtle hatchlings (Caretta caretta) emerging over 4 days in Florida; for green turtles (Chelonia mydas), Hendrickson (1958) documented that nests in Malaysia and Sarawak produced hatchlings for up to 8 days; whilst Diamond (1976) found that hawksbill (Eretmochelys imbricata) nests on Cousin Island, Seychelles, were active for up to 4 days. Similarly, on the Greek Island of Kefalonia, we have shown that emergence from individual loggerhead turtle nests may occur on up to 11 nights (Hays and Speakman 1992). It is logical to suppose that asynchronous emergence relates to thermal gradients within nests, since the incubation duration of sea turtle eggs is related to temperature, with eggs hatching quicker when the temperature is higher. Here we test this hypothesis by measuring thermal variations within loggerhead turtle nests and comparing these variations to the patterns of hatchling emergence.
Neopolystoma liewi sp. n. is described from the conjunctival cavity of the Malayan box turtle Cuora amboinensis (Daudin, 1802), in Peninsular Malaysia. This is the first record of Neopolystoma in Malaysia and the fourth polystomatid species described from C. amboinensis. Of the 27 Malayan box turtles examined, 8 were found to be infected. A maximum of 2 parasites per eye and 4 individuals per host was recorded. N. liewi sp. n. differs from all other members of the genus by possessing few and short genital spines and small marginal hooks. The oncomiracidium has 64 ciliated cells arranged symmetrically about the sagittal axis.
Parapleurogonius brevicecum gen. et sp. n. is described from the freshwater turtle, Kachuga trivittata, in Selangor, Malaysia. Parapleurogonius is most closely related to Pleurogonius Looss, 1901, but from which it can be distinguished by the termination of the ceca at or just overlapping the anterior border of the testes and the pretesticular position of the excretory pore. Additionally, Parapleurogonius is described from a freshwater turtle, whereas Pleurogonius is only known from marine hosts.
Stunkardia minuta sp. n. was recovered from the small intestine and rectum of 5 box-tortoises (Cuora amboinensis) in Malaysia. The average body size (L X W) is 11-42 X 2-35 mm; oral sucker 1-51 X 1.02; oral pouches 0-21 X 0.18; ventral sucker 1-67 X 1-43; oesophageal bulb 0-54 X 0-54; ant. testis 0-95 X 0-98; post. testis 0-94 X 0.94; seminal vesicle 0-82 X 0-24; ootype 0-21 X 0-41; ovary 0-41 X 0-34; and egg 121 X 83 micrometer. Although morphologically similar to S. dilymphosa, S. minuta is distinct from any other reported member of the Paramphistomidae.
The diversity of monogeneans from Southeast Asia was examined using information from the literature to show their diversity at different taxonomic (subclass, family, genera, species) levels. Knowledge of monogeneans is still incomplete in Southeast Asia and the present numbers of monogeneans are likely an underestimate of what is present on/in aquatic organisms in the region, since so few hosts have been examined. An estimate of the possible numbers of monogeneans that could be present on/in fishes and turtles in Peninsular Malaysia indicates that only 8% of the monogeneans are presently known. Analysis of the available data on monogenean diversity (or species richness) at different taxonomic levels will provide useful information on their distribution patterns. There is an uneven distribution of investigations on this topic and Malayan fauna is considered to be representative of the Southeast Asian fauna. Southeast Asian (Sundaland) monogeneans are related (at the generic level) to the monogenean fauna of South China, India and Africa.
A potential advantage of group movement in animals is increased locomotion efficiency. This implies a reduced energetic cost for individuals that occur in larger groups such as herds, flocks and schools. When chelonian hatchlings hatch in the underground nest with finite energy for their post-hatching dispersal phase, they face the challenge of minimizing energetic expenditure while escaping the nest. The term 'social facilitation' has been used to describe the combined digging effort of sea turtle hatchlings during nest escape. Given that in a normal clutch, a substantial part of the energy reserve within the residual yolk is used by hatchlings in the digging out process, a decreased cohort size may reduce the energy reserve available to cross the beach and sustain the initial swimming frenzy. This hypothesis was experimentally tested by varying cohort size in hatchling green turtles (Chelonia mydas) and measuring energy expenditure during the nest escape process using open-flow respirometry. The energetic cost of escaping through 40 cm of sand was calculated to vary between 4.4 and 28.3 kJ per individual, the cost decreasing as the number of individuals in the cohort increased. This represents 11-68% of the energy contained in a hatchling's residual yolk at hatching. The reduced energetic cost associated with large cohorts resulted from both a lower metabolic rate per individual and a shortened nest escape time. We conclude that synchronous digging activity of many hatchlings during nest escape evolved not only to facilitate rapid nest emergence but also to reduce the energetic cost to individuals.
Selingan Island off Sandakan, Sabah is a famous turtle nesting ground and a part of the Turtle Islands Park (TIP) within the Coral Triangle region of Malaysia. This small island faces the serious problem of beach erosion that is reducing the turtle nesting area. Sabah Parks deployed stone revetments in 2005, followed by placement of reef balls at the southern part of the Selingan Island in 2007 for protecting the shoreline. The objective of this study was to determine the effectiveness of these measures for shoreline protection. Shoreline changes were determined from satellite images, beach profiling and field observations. Satellite images from 2010 to 2016 were obtained from Google Earth Pro analyzed to examine the changes in the shape and size of the island with QGIS software. Beach profiling was performed in December 2017 at three sites and compared with the condition in 2011. The findings indicated that the shape of the island was squeezed towards the east where the reef balls were located. The size of the island has not changed much in 9 years after the deployment of the reef balls, but a high volume of sediments accumulated at the south due to the presence of shoreline protection. Generally, the man-made structures in Selingan Island are effective in trapping the sediment and providing more nesting area for turtles. It is recommended that the shoreline dynamics of the island should be regularly monitored for better understanding of the changes and taking appropriate actions.
This study reports the discovery of the exclusive predation of sea turtle hatchlings by several juvenile blacktip reef sharks (Carcharhinus melanopterus) in Chagar Hutang bay on Redang Island, Malaysia, in the South China Sea. Three dead specimens of C. melanopterus were retrieved from ghost nets, and the entire digestive tracts of these sharks solely contained the partially digested bodies of sea turtle hatchlings, with no evidence of the remains of any other prey. Thus, juvenile C. melanopterus may opportunistically feed primarily on turtle hatchlings during times when hatchling abundance is high.
A survey was carried out at Gunung Panti Forest Reserve, Johor from 3-7 August 2006, 2-5 June 2008, and 28-31 July 2008 to inventory the herpetofauna therein. An updated checklist for the area which incorporates findings from previous studies is provided. In total, 37 species of frogs, 1 turtle, 27 lizards, and 11 snakes have been recorded from Gunung Panti Forest Reserve, Johor.
The Green Turtle (Chelonia mydas) and Olive Ridley Turtle (Lepidochelys olivacea) are the only sea turtles with recorded landings in the Pulau Pinang coastal area. The Green Turtle has been the most abundant and widely distributed sea turtle in this area since it was first surveyed in 1995. Statistical analysis by the Pulau Pinang Department of Fisheries on the distribution of sea turtles from 2001 through 2009 has identified Pantai Kerachut and Telok Kampi as the most strongly preferred beaches for Green Turtle landings, with records for almost every month in every year. Green Turtle tracks and nests have also been found along the coast of Pulau Pinang at Batu Ferringhi, Tanjong Bungah, Pantai Medan, Pantai Belanda, Telok Kumbar, Gertak Sanggul, Moonlight Beach, Telok Duyung, Telok Aling, Telok Bahang and Telok Katapang. The Olive Ridley Turtle is present in smaller numbers; landing and nesting have only been recorded on a few beaches. There are no previous records of Olive Ridley landings at Pantai Kerachut and Telok Kampi, but tracks and nests have been found at Telok Kumbar, Tanjong Bungah, Pantai Medan, Telok Duyung and Gertak Sanggul. A Turtle Conservation Centre has been established at Pantai Kerachut to protect these species from extinction in Pulau Pinang. This paper presents details of the records and distribution of sea turtles in Pulau Pinang from 1995 through 2009.
The Green Turtle (Chelonia mydas) and Olive Ridley Turtle (Lepidochelys olivacea) are the only sea turtles with recorded landings in the Pulau Pinang coastal area. The Green Turtle has been the most abundant and widely distributed sea turtle in this area since it was first surveyed in 1995. Statistical analysis by the Pulau Pinang Department of Fisheries on the distribution of sea turtles from 2001 through 2009 has identified Pantai Kerachut and Telok Kampi as the most strongly preferred beaches for Green Turtle landings, with records for almost every month in every year. Green Turtle tracks and nests have also been found along the coast of Pulau Pinang at Batu Ferringhi, Tanjong Bungah, Pantai Medan, Pantai Belanda, Telok Kumbar, Gertak Sanggul, Moonlight Beach, Telok Duyung, Telok Aling, Telok Bahang and Telok Katapang. The Olive Ridley Turtle is present in smaller numbers; landing and nesting have only been recorded on a few beaches. There are no previous records of Olive Ridley landings at Pantai Kerachut and Telok Kampi, but tracks and nests have been found at Telok Kumbar, Tanjong Bungah, Pantai Medan, Telok Duyung and Gertak Sanggul. A Turtle Conservation Centre has been established at Pantai Kerachut to protect these species from extinction in Pulau Pinang. This paper presents details of the records and distribution of sea turtles in Pulau Pinang from 1995 through 2009.
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 found for 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.
Chelonian exhibit temperature dependent sex determination, and ex situ incubation of eggs in conservation hatcheries may render a gender bias. The gender of juvenile Painted terrapins (Batagur borneoensis) produced at a conservation hatchery in Malaysia was determined by endoscopy of the gonads. Circulating reproductive hormones (testosterone, progesterone and estradiol) were profiled for 31 juveniles and nine captive-reared non-breeding adult terrapins. Endoscopy revealed a gender bias of 96.8% (30/31) females. Testosterone levels in the juvenile females (2.49 ± 1.29) were significantly lower than that of the adult females (12.20 ± 4.29), and lower than values in the juvenile male (9.36) and adult males (27.60, 35.62). The progesterone levels in the juvenile females (107.12 ± 68.68) were significantly higher than that of the adult females (51.13 ± 24.67), but lower than values in the juvenile male (33.27) and adult males (3.43, 8.51). Estrogen levels were significantly lower in the juvenile females (1.57 ± 1.35) compared to the adult females (77.46 ± 53.45). Negative correlations were observed between levels of progesterone and testosterone, and progesterone and estrogen. A positive correlation was noted between estrogen and testosterone. The present study constitutes the first attempt to determine the gender and reproductive hormone profiles of juvenile Painted terrapins produced by ex situ incubation, and captive non-breeding adults. Endoscopy of the gonads is a useful techniques for gender determination among juvenile turtles, while the use of testosterone as a gender biomarker warrants further investigation.
A variety of trace metals were measured in the egg contents of three clutches of Chelonia mydas collected from Kuala Terengganu state in Peninsular Malaysia. We quantified Mn, Cu, Zn, Se (essential trace metals) and As (anthropogenic pollutant) at several developmental stages obtained by incubating eggs at two different temperatures (27 °C and 31 °C). The incubation temperatures were chosen because they produce predominantly male or predominantly female hatchlings, respectively. The eggs were removed from the sand and washed before being placed in incubators, to ensure that the only possible source of the detected metals was maternal transfer. Other metals: Mo, Co, Ni, Cd, Sn, Sb, Hg, Tl and Pb (all non-essential metals) were detected at concentrations below the lower limit of quantitation (LLOQ). Trace metal concentrations, particularly [Zn], increased during development, other metals (Cu, As, Se and Cr) accumulated to a lesser degree than zinc but no significant differences were observed between the incubation temperatures at any stage of incubation. To date, only a few studies on trace metals in turtle embryos and hatchlings have been reported; this study will provide basic knowledge on the accumulation of trace metals during development at two different incubation temperatures.