Study

Incubation temperatures and sex-ratios in the Malaysian leatherback turtle Dermochelys coriacea

  • Published source details Chan E.H. & Liew H.C. (1995) Incubation temperatures and sex-ratios in the Malaysian leatherback turtle Dermochelys coriacea. Biological Conservation, 74, 169-174.

Actions

This study is summarised as evidence for the following.

Action Category

Relocate nests/eggs to a hatchery: Sea turtles

Action Link
Reptile Conservation

Relocate nests/eggs for artificial incubation: Sea turtles

Action Link
Reptile Conservation
  1. Relocate nests/eggs to a hatchery: Sea turtles

    A replicated, randomized study in 1986 on a sandy beach in Rantau Abang, Malaysia (Chan & Liew 1995; same experimental set-up as Chan 1989) found that moving leatherback turtle Dermochelys coriacea eggs to an on-beach hatchery resulted in almost all female hatchlings, and that hatching success did not vary due to the number of eggs buried together in the hatchery. In total, 168 of 169 (99%) hatchlings were female, and the sex of one hatchling could not be determined. Hatching success was similar across all nest sizes (23–25 eggs: 13–48%; 48–50 eggs: 22–44%; 72–75 eggs: 9–51%; 96–100 eggs: 15–47%). In 1986, eggs were collected from a total of 13 natural nests and buried in groups of 23–25 (7 nests), 48–50 (3 nests), 72–75 (3 nests) or 96–100 eggs/nest (3 nests).  From each nest, 2–20 hatchlings were selected for sexing. These hatchlings were euthanised in chloroform and sex was determined by removing and examining the gonads. Hatching success was determined by counting the number of hatchlings to emerge from each nest.

    (Summarised by: William Morgan)

  2. Relocate nests/eggs for artificial incubation: Sea turtles

    A replicated, randomized study in 1986 on one sandy beach in Rantau Abang, Malaysia (Chan & Liew 1995; same experimental set-up as Chan 1989) found that relocating leatherback turtle Dermochelys coriacea eggs for artificial incubation in Styrofoam boxes resulted in all male hatchlings. Of the hatchings that were sexed, 29 of 29 were male. Eggs were collected from natural nests (only yolked eggs of normal size) and three groups of 25 eggs were incubated in Styrofoam boxes (temperature range 27–29°C). Temperatures were monitored three times/day (0900, 1200 and 1500 h) with a mercury thermometer inserted horizontally through a hole in the side of the box. A sample of 9, 9 and 11 hatchlings from each box were selected for sexing. These hatchlings were euthanised in chloroform and sex was determined by removing and examining the gonads.

    (Summarised by: William Morgan)

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