Translocate adult or juvenile reptiles: Sea turtles

Overall effectiveness category Awaiting assessment
Number of studies: 2
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Background information and definitions

Translocations involve the intentional capture, movement and release of wild-caught reptiles into the wild to re-establish a population that has been lost, or to augment an existing population. This can reduce the risk of inbreeding; help safeguard small populations from extinction due to catastrophic events and/or increase the occupied range. Translocations can also be used to move reptiles to areas where threats have been removed, such as islands where invasive predators have been eradicated. However, translocations are typically expensive and may risk spreading pathogens to previously unexposed areas.

Release techniques vary considerably, from ‘hard releases’ involving the simple release of individuals into the wild, to ‘soft releases’ that involve a variety of adaptation and acclimatisation techniques before release or post-release feeding and care.

This action includes studies which may combine different release techniques, but studies that explicitly test these different techniques are summarized separately under Use holding pens or enclosures at release site prior to release of wild reptiles; Use holding pens or enclosures at release site prior to release of captive-bred reptiles and Release reptiles into burrows.

This action includes the translocation of wild juvenile or adult reptiles. Relocations of eggs and nests, releases of captive bred individuals and releases of head-started individuals (reptiles of wild-origin reared in captivity prior to release) are discussed under: Relocate nests/eggs; Release captive-bred reptiles into the wild; Head-start wild-caught reptiles for release and Release reptiles born/hatched in captivity from wild-collected eggs/wild-caught females without rearing. For studies that release reptiles outside of their native range see Release reptiles outside of their native range.

Translocations that are carried out to mitigate against specific threats (for example translocating problem individuals away from a specific area, or translocating individuals away from development areas) are summarized under Mitigation translocations – Translocate problem reptiles; Translocate reptiles away from threats and Temporarily move reptiles away from short-term threats.

Due to the number of studies found, this action has been split by species group, though no studies were found for amphisbaenians. See here for: Tortoises, terrapins, side-necked & softshell turtles; Snakes; Lizards; Crocodilians or Tuatara.

Study locations

Key messages

Two studies evaluated the effects of translocating sea turtles on their populations. One study was global and one was in Japan.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (2 STUDIES)

Abundance (1 study): One global review reported that zero of four sea turtle translocations were considered successful.
Reproductive success (1 study): One global review reported that zero of four sea turtle translocations found that breeding occurred.
Survival (1 study): One study in Japan found that at least two of five wild-caught hawksbill turtles survived at least six months following release.

BEHAVIOUR (1 STUDY)

Behaviour change (1 study): One study in Japan found that at least two of five wild-caught hawksbill turtles returned to their point of capture after release.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A review of worldwide translocation programmes for reptiles during 1962–1990 (Dodd & Seigel 1991) found that at least half of those involving sea turtles were unsuccessful. Two of four (50%) programmes were considered unsuccessful, and for a further two the result was unknown. In addition, breeding was not observed in three of four programmes, and for the other the result was unknown. The origin of individuals (wild populations or captive-bred) was not described for all programmes. Published and unpublished literature was searched.
Study and other actions tested
Referenced paper
Dodd C.K.Jr. & Seigel R.A. (1991) Relocation, repatriation, and translocation of amphibians and reptiles: are they conservation strategies that work? Herpetologica, 47, 336-350.
A study in 2005–2006 off the coast of an island in southwestern Japan (Okuyama et al. 2010) found that translocated hawksbill turtles Eretmochelys imbricata that were held in captivity before release tended to return to their point of capture. Five wild-caught turtles (held in captivity for 4 months) were tracked for 2–8 days, and two were recaptured 182–199 days after release at their original point of capture (around 5–15 km from release site). An additional four head-started turtles were tracked for 4–9 days and a fifth turtle was tracked intermittently for 10 months. Five wild turtles were captured and held in captivity for four months in large rearing tanks (2 or 5 kl). Five head-started turtles were raised for 2.5 years after being hatched from eggs collected on the island. All turtles were fitted with radio transmitters and released in April 2005 following 1 h sea-acclimation in an enclosure net (4 × 4 × 5 m). Turtles were tracked using 12 fixed receivers deployed on the ocean floor (18 m deep).
Study and other actions tested
Referenced paper
Okuyama J., Shimizu T., Abe O., Yoseda K. & Arai N. (2010) Wild versus head-started hawksbill turtles Eretmochelys imbricata: post-release behavior and feeding adaptions. Endangered Species Research, 10, 181-190.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Reptile Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Translocate adult or juvenile reptiles: Lizards Action Link	Awaiting assessment	17	Synopsis Link
Release reptiles outside of their native range Action Link	Awaiting assessment	7	Synopsis Link
Release reptiles into burrows Action Link	Awaiting assessment	1	Synopsis Link