tsrp63entire

5.3.5 Topic 18—Ex situ conservation techniques
Three species of native frogs (Archey’s, Hochstetter’s and Maud Island) have been held in
captivity since 2000 as part of a captive management research programme. However, the
mortality rate of these frogs has been high. This was thought to be caused by a combination
of factors relating to husbandry, particularly the control of MBD (see Shaw & Holzapfel 2008).
Although several egg clusters have been produced by Archey’s frogs and Hochstetter’s frogs in
captivity (Auckland Zoo, Hamilton Zoo, University of Canterbury), none have survived past the
froglet stage.
An additional barrier to captive breeding is the inability to physically identify male and female
frogs. Although non-invasive sex identification techniques using hormone assays have recently
been developed for native frogs (Germano et al. 2012), assisted reproductive technologies
have not yet been used to increase the reproductive success and output of captive breeding
populations. The development of artificial insemination and in vitro fertilisation are additional
ex situ tools that could help to secure native frogs.
To date, cryopreservation techniques for the storage of sperm and eggs/embryos have only been
developed successfully for a few amphibian species worldwide. Such development is considered
beyond the scope of this 5-year plan, but may become an important focus in the future.
Issues
Issue 18.1:
Issue 18.2:
Mortality rates in captive frog populations that have been established for breeding
are very high.
Captive frog populations that have been established for breeding have had very
limited success.
Objectives and actions
Objective 18.1:
Objective 18.2:
To reduce mortality rates in captivity to natural levels (as identified in
Action 16.1).
To increase the reproductive success and offspring survival rates in captive
breeding populations.
Action Accountability Priority
18.1 Review and, where required, refine husbandry
techniques to reduce mortality in captivity for the
duration of this plan.
18.2 Review the diet (mineral and nutritional content) of
captive frogs by analysing the stomach contents
and faecal samples of wild frogs by 2015.
18.3 Identify and provide an appropriate microhabitat in
captive environments to maximise the success of
captive breeding and juvenile survival by 2018.
Recovery Group
Captive institutions
Recovery Group
Captive institutions
Recovery Group
Captive institutions
Essential
Essential
Essential
32 Bishop et al.—Native frog recovery plan, 2013–2018