Nesting Ecology Of The Green Turtle, Chelonia Mydas And Hawksbill Turtle, Eretmochelys Imbricata On The West Coast Of Peninsular Malaysia
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Date
2016-08
Authors
Mohd Salleh, Sarahaizad
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Abstract
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. Poisson State Space Modeling indicated that the fluctuations in the number of nests in Penang Island relates to temperature rather than precipitation. The air temperature investigated in this study might not directly affect the physiology and behaviour of nesting green turtles, but is assumed to closely relate to sand and water temperature. Green turtle tend to build nests at nesting sites that are composed of a high percentage of 1 mm diameter sand particle-size, compared to 2 mm, 425 μm, 250 μm, 125 μm, and 63 μm. A Split Clutch Design Method was conducted in
Penang Island, where clutch size of green turtle was split into two equal half of eggs and incubated in Styrofoam boxes and Open Area plot. Hatching success produced in the Open Area nest was slightly higher in percentage compared to hatching success of nest from Styrofoam box. In Melaka, a total of 481 hawksbill nests were observed in 2013 and 463 nests were observed in 2014. The distribution of hawksbill turtle nests in Melaka was not uniformly distributed among the 20 nesting beaches, and a high number of nests were observed in Padang Kemunting, Kem Terendak, and Pulau Upeh. Results of this study indicate the population size of hawksbill turtles in Melaka to increase slightly or have been stable in the last 25 years. The current increasing nesting status of hawksbill turtle in Melaka might be helpful for reference purposes for hawksbill conservation programme at nesting beaches in this world, because the hawksbill turtle is known to nest at restricted areas and is listed as a critically endangered species by the International Union for Conservation of Nature (IUCN). The current conservation efforts of green turtle in Penang Island is focused mainly at Kerachut and Teluk Kampi; therefore, it is recommended small sanctuaries be set aside at identified nesting beaches of Penang Island improve the protection of green turtle to a higher level.
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Nesting data of the green turtle, Chelonia mydas in Penang Island , and hawksbill turtle, Eretmochelys imbricata in Melaka.