Study

Emergence success and sex ratio of natural and relocated nests of olive ridley turtles from alas purwo national Park, East Java, Indonesia

  • Published source details Maulany R.I., Booth D.T. & Baxter G.S. (2012) Emergence success and sex ratio of natural and relocated nests of olive ridley turtles from alas purwo national Park, East Java, Indonesia. Copeia, 738-747.

Actions

This study is summarised as evidence for the following.

Action Category

Protect nests and nesting sites from predation using artificial nest covers: Sea turtles

Action Link
Reptile Conservation

Relocate nests/eggs to a hatchery: Sea turtles

Action Link
Reptile Conservation
  1. Protect nests and nesting sites from predation using artificial nest covers: Sea turtles

    A randomized, controlled study in 20092010 on a sandy beach in East Java, Indonesia (Maulany et al. 2012) found that using artificial nest covers to protect olive ridley turtle Lepidochelys olivacea nests did not improve hatching success rates. All nests, including those with artificial covers and those without were predated within one week of being laid and no eggs hatched. Olive ridley turtle nests laid in MayJuly 20092010 along an 18 km stretch of sandy beach in a national park were randomly selected to be either protected by artificial nest covers (2009: 5; 2010: 5) or unprotected (2009: 6; 2010: 14). Nests were excavated to count the number of eggs and re-buried. Protected nests were covered with a 40 x 50 x 50 cm cylindrical galvanized wire cage buried 20 cm into the sand and secured with wooden stakes. All nests were temporarily covered prior to hatching to enable hatchlings to be counted. After emergence, all nests were dug up and unhatched eggs counted.

    (Summarised by: Katie Sainsbury)

  2. Relocate nests/eggs to a hatchery: Sea turtles

    A randomized, controlled study in 2009–2010 on a sandy beach in East Java, Indonesia (Maulany et al. 2012) found that relocating olive ridley turtle Lepidochelys olivacea nests to an on-beach hatchery resulted in higher hatching success than for nests left in situ. The hatching success of nests moved to an on-beach hatchery was 54–73% of nests laid (2009: 39 of 53 nests; 2010: 30 of 56), whereas all nests left in place (11–19 nests/year) were lost to predation within one week of being laid and no eggs hatched. Olive ridley turtle nests laid in May–July 2009–2010 along an 18 km stretch of sandy beach in a national park were randomly selected to be moved to an on-beach hatchery (2009: 53 nests; 2010: 56 nests) or left in place (2009: 11; 2010: 19) within 200 m of the hatchery. Nests moved to the hatchery were buried 30 cm apart in artificially dug nests (40 cm deep). Nests left in place were excavated to count the number of eggs and re-buried. Some nests left in place were also protected using artificial nest covers (see original paper for details). All nests were temporarily covered prior to hatching to enable hatchlings to be counted. After emergence, all nests were dug up and unhatched eggs counted.

    (Summarised by: Katie Sainsbury)

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