Study

Securing the future of threatened tuatara populations with artificial incubation

  • Published source details Keall S.N., Nelson N.J. & Daugherty C.H. (2010) Securing the future of threatened tuatara populations with artificial incubation. Herpetological Conservation and Biology, 5, 555-562.

Actions

This study is summarised as evidence for the following.

Action Category

Breed reptiles in captivity: Tuatara

Action Link
Reptile Conservation

Bring threatened wild populations into captivity

Action Link
Reptile Conservation

Relocate nests/eggs for artificial incubation: Tuatara

Action Link
Reptile Conservation
  1. Breed reptiles in captivity: Tuatara

    A replicated study in 1990–2007 in artificial enclosures in North Island, New Zealand (Keall et al. 2010) reported that wild tuatara Sphenodon punctatus bred multiple times in captivity but that fewer than half of eggs hatched successfully. Over 16 years, 241 of 553 eggs (44%) laid by tuatara in captivity hatched successfully. Clutches were laid in 13 of 16 years by 15 of 22 females. The first clutches were laid 2–8 years after tuatara were brought into captivity. Hatching success and adult survival varied between tuatara taken from different islands (see original paper for details). Three captive-born females also produced three clutches during the study. In 1990–1992, four populations of tuatara were brought into captivity from four islands (6–15 individuals/island) to one of three captive facilities pending eradication of Pacific rats Rattus exulans. Tuatara were housed in predator-proof outdoor enclosures. In 1992–2007, eggs were moved to a separate facility for artificial incubation in dampened vermiculite (see original paper for details). Overall, four clutches were induced and 27 clutches were laid naturally. Hatchlings were returned to their source facility at one week–11 months old. Eggs that perished shortly after being laid (5–16 eggs in two clutches) and eggs laid by artificially-incubated females were excluded from results.

    (Summarised by: Katie Sainsbury)

  2. Bring threatened wild populations into captivity

    A replicated study in 1990–2007 in three captive facilities on North Island, New Zealand (Keall et al. 2010) found that most wild tuatara Sphenodon punctatus brought into captivity survived and bred. Over 16 years, eight of eight and six of six tuatara from two island populations survived in captivity. In addition, 11 of 15 tuatara from a third island survived and were released back into the wild (the fate of the remaining four is not described) and five of 11 tuatara from a fourth island survived in captivity. Clutches were laid in 13 of 16 years by 15 of 22 females, 44% of eggs hatched (241 of 553 eggs) and second-generation females produced three clutches. In 1990–1992, entire populations of tuatara from four islands were captured (6–15 individuals/island) and placed in one of three captive facilities pending eradication of pacific rats Rattus exulans. Tuatara were housed in predator-proof outdoor enclosures. In 1992–2007, eggs were moved to a separate facility and artificially incubated (see original paper for details). Hatchlings were returned to their source facility after one week to11 months. Hatching success does not include eggs that perished shortly after being laid (5–16 eggs in 2 clutches) and eggs laid by second-generation females.

    (Summarised by: Katie Sainsbury)

  3. Relocate nests/eggs for artificial incubation: Tuatara

    A replicated study in 1990–2007 in artificial enclosures in North Island, New Zealand (Keall et al. 2010) found that less than half of relocated artificially incubated wild tuatara Sphenodon punctatus eggs hatched. Over 16 years, 44% of eggs (241 of 553 eggs) laid by wild tuatara in captivity and relocated for artificial incubation hatched successfully. The first clutches to hatch successfully were laid 2–8 years after tuatara were brought into captivity. Second-generation female hatchlings that had been artificially incubated went on to produce three clutches during the study. In 1990–1992 four entire tuatara populations from four islands (6–15 individuals/island) were placed in one of three captive facilities pending eradication of pacific rats Rattus exulans. Clutches laid by 15 females were moved to a separate facility for artificial incubation in dampened vermiculite at temperatures to ensure an even sex ratio (see original paper for details). Four clutches were induced and the remaining 27 were laid naturally. Eggs that perished shortly after being laid (5–16 eggs in 2 clutches) and eggs laid by artificially incubated females were excluded from the data.

    (Summarised by: Katie Sainsbury)

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