Relocate nests/eggs to a hatchery: Tortoises, terrapins, side-necked & softshell turtles

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

Reptile nests may be relocated away from specific threats (e.g. egg collecting, flooding, erosion, predation, or being crushed on roads) and reburied in an organised ‘hatchery’. Hatcheries consist of a defined location on or near the nesting beach, well above the high tide line, that is often fenced and patrolled. Nests/eggs collected from the beach are then reburied within the hatchery, where they can be closely monitored.

Burying a potentially large number of nests/eggs within a relatively small area may present a number of risks, and the consequences of disturbances such as flooding or poaching could be particularly severe. Other environmental variables at the hatchery location (e.g. temperature and humidity) may also impact on the sex, size, shape, colour, behaviour, movement ability and post-hatching growth of the hatchlings (Warner & Andrews 2002, Booth et al. 2006), and should be carefully considered when selecting the location.

Due to the number of studies found, this action has been split by species group, though no studies were found for amphisbaenians. See her for: Sea turtles; Snakes & lizards; Crocodilians; Tuatara.

For studies that discuss moving nests/eggs to other locations on the beach, but not to a hatchery, see Relocate nests/eggs to a nearby natural setting (not including hatcheries), and for those that discuss the effects of relocating eggs into artificial settings, including into polystyrene boxes and other containers, see Relocate nests/eggs for artificial incubation.

^{Booth D.T. (2006) Influence of incubation temperature on hatchling phenotype in reptiles. Physiological and Biochemical Zoology, 79, 274–281.}

^{Warner D.A. & Andrews R.M. (2002) Laboratory and field experiments identify sources of variation in phenotypes and survival of hatchling lizards. Biological Journal of the Linnean Society, 76, 105–124.}

Study locations

Key messages

Two studies evaluated the effects on tortoise, terrapin, side-necked and softshell turtle populations of relocating nests/eggs to a hatchery. One study was in Costa Rica and Venezuela.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (2 STUDIES)

Reproductive success (2 studies): One replicated, controlled study in Venezuela found that yellow-headed sideneck turtle eggs relocated to a hatchery had higher hatching success than both natural nests and artificially incubated eggs. One study in Costa Rica reported that 80% of Nicaraguan slider eggs in a hatchery hatched successfully.

BEHAVIOUR (0 STUDIES)

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 study in 1991 on a river in northern Costa Rica (Pritchard 1993) reported that some Nicaraguan slider Trachemys emolli eggs taken from the wild to a hatchery (as part of a ranching program) hatched successfully. The author reported that approximately 80% of eggs collected hatched successfully in the hatchery, and that 30% of hatchlings were released into the wild. In 1991, eggs from 310 nests were collected (average of 20 eggs/nest) within 24 hours of laying and reburied in soil in an enclosed area. Collection was carried out by local people, who received 50% of the funds generated by sale of the turtles.
Study and other actions tested
Referenced paper
Pritchard P. (1993) A ranching project for freshwater turtles in Costa Rica. Chelonian Conservation and Biology, 1, 48.
A replicated, controlled study in 2009 on two rivers in Southern Venezuela (Herández et al. 2010) found that relocating eggs of yellow-headed sideneck turtles Podocnemis unifilis to a hatchery resulted in higher hatching success compared to eggs from natural nests and eggs incubated artificially. Results were not statistically tested. Hatching success was higher for eggs from the hatchery (88%) than for eggs from both natural nests (63%) and artificially incubated eggs (42%). Five eggs each from 27 nests (136 total) at one river were moved to a hatchery and reburied in a trench (200 x 40 x 30 cm) using sand from the nesting site. The area was protected by a 1.5 m metal mesh fence, and two staff monitored the site and poured 5 litres of water over the trench each week. All eggs from 13 nests (401 total) at the second river were placed in sand-filled polystyrene containers and incubated indoors in ambient conditions. All eggs from a further 51 nests from the first river were left in place. In February 2009, a 6 km and 13 km stretch of each river was searched for nests. In May, these locations were revisited to assess hatching success.
Study and other actions tested
Referenced paper
Herández O., Espinosa-Blanco A.S., May Lugo C., Jimenez-Oraa M. & Seijas A.E. (2010) Artificial incubation of yellow-headed sideneck turtle Podocnemis unifilis eggs to reduce losses to flooding and predation, Cojedes and Manapire Rivers, southern Venezuela. Conservation Evidence, 7, 100-105.

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

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This Action forms part of the Action Synopsis:

Reptile Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Relocate nests/eggs for artificial incubation: Tuatara Action Link	Awaiting assessment	2	Synopsis Link
Relocate nests/eggs to a hatchery: Sea turtles Action Link	Awaiting assessment	22	Synopsis Link
Relocate nests/eggs for artificial incubation: Sea turtles Action Link	Awaiting assessment	15	Synopsis Link